# BoringToolsKit full tool knowledge > Generated from the same catalogue and authored methodology sources as the live site. Records labeled catalogue do not claim authored formula evidence. - [Machine-readable catalogue](https://boringtoolskit.com/tool-knowledge.json) - [Reproducible scenario research](https://boringtoolskit.com/research/) ## Tool: 1031 Exchange Calculator - URL: https://boringtoolskit.com/1031-exchange-calculator/ - Category: Real Estate - Evidence: catalogue - Description: 1031 exchange calculator: capital gains tax deferred and any taxable boot in a like-kind exchange. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: 401k Employer Match Calculator - URL: https://boringtoolskit.com/401k-employer-match-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate employee contributions, employer match, unclaimed match, and per-paycheck amounts. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Employer match = salary × employee contribution % matched up to the employer's limit, applied per pay period. The calculator computes how much your match is worth and how it accumulates with your own contribution. - Assumptions: Match is a percentage of salary, capped at the employer's limit. | The employee contribution qualifies for the match only up to the stated cap. | Pay periods are annualized for the estimate. - Sources: https://www.investopedia.com/terms/4/401kplan.asp | https://boringtoolskit.com/methodology/ ## Tool: 50 30 20 Budget Calculator - URL: https://boringtoolskit.com/50-30-20-budget-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: 50/30/20 budget calculator: split after-tax income into needs, wants, and savings. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: 529 College Savings Calculator - URL: https://boringtoolskit.com/529-college-savings-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: 529 college savings calculator: projected value of monthly contributions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: A1c Calculator - URL: https://boringtoolskit.com/a1c-calculator/ - Category: Health - Evidence: catalogue - Description: A1c calculator: estimated average glucose from HbA1c. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Absolute Value Calculator - URL: https://boringtoolskit.com/absolute-value-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Absolute value calculator: distance from zero. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: |x| = x if x ≥ 0, else −x. - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: AC BTU Calculator - URL: https://boringtoolskit.com/ac-btu-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: AC BTU calculator: estimate cooling capacity needed for a room from area and conditions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Acceleration Calculator - URL: https://boringtoolskit.com/acceleration-calculator/ - Category: Physics - Evidence: authored-methodology - Description: Calculate acceleration from the change in velocity over time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Acceleration (a) = (final velocity − initial velocity) ÷ time. Units: m/s². - Assumptions: Velocities are in m/s and time in seconds. | Acceleration is assumed constant over the interval. | Time must be positive. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: After Repair Value Calculator - URL: https://boringtoolskit.com/after-repair-value-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate after-repair value (ARV) of a fix-and-flip property using comparable sales. Enter comps and see the blended estimate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: After-repair value (ARV) = average of comparable sold prices + value of improvements. The tool averages the entered comparable prices and adds the adjustment value to estimate the property's value after renovation. - Assumptions: Comparable values are entered by the user from recent similar sales. | The adjustment captures the uplift from planned improvements. | Zero-value comps are ignored when averaging. - Sources: https://www.investopedia.com/terms/a/after-repair-value.asp | https://boringtoolskit.com/methodology/ ## Tool: Age Calculator - URL: https://boringtoolskit.com/age-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate exact calendar age, total elapsed days, and time until the next birthday. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Calendar age subtracts complete years, then complete months, then remaining days; total days uses UTC date boundaries to avoid daylight-saving shifts. - Assumptions: Dates use the proleptic Gregorian calendar implemented by the browser. | Total weeks are total days divided by seven and may be fractional. | Legal age rules for leap-day birthdays can vary by jurisdiction. - Sources: https://www.loc.gov/research-centers/science-and-business/about-this-research-center/ | https://tc39.es/ecma262/multipage/numbers-and-dates.html#sec-date-objects ## Tool: Air Fryer Time Calculator - URL: https://boringtoolskit.com/air-fryer-time-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Air fryer time calculator: temp and time by food. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Alcohol Dilution Calculator - URL: https://boringtoolskit.com/alcohol-dilution-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Alcohol dilution calculator: find how much water to add to bring spirits or concentrates to a target ABV. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Amazon Seller Fees Calculator - URL: https://boringtoolskit.com/amazon-seller-fee-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Free Amazon seller fee calculator: estimate referral, fulfillment, storage, and FBA fees plus net profit and margin , with editable 2026 assumptions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Referral fee = price × category rate (most categories ~15%). Total fees = referral + fulfillment/closing + other. Net = price − product cost − total fees. Margin % = net ÷ price. - Assumptions: The referral rate matches the item's category. | Fulfillment costs reflect the seller's method (FBA or merchant). | Returns and advertising are excluded. - Sources: https://en.wikipedia.org/wiki/Fulfillment_by_Amazon | https://boringtoolskit.com/methodology/ ## Tool: Amortization Calculator - URL: https://boringtoolskit.com/amortization-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate your monthly loan payment and full amortization schedule, and see how extra monthly payments shorten the term and reduce total interest. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Monthly payment = P × r ÷ (1 − (1 + r)^−n), where P = principal, r = monthly rate (annual ÷ 12), n = number of months. Each payment: interest = balance × r; principal = payment − interest; balance decreases until zero. - Assumptions: A fixed annual interest rate applied monthly. | Equal payments made at the end of each month. | No extra payments, fees, or rate changes. - Sources: https://www.calculatorsoup.com/calculators/financial/amortization-schedule-calculator.php | https://boringtoolskit.com/methodology/ ## Tool: Ancient Unit Converter - URL: https://boringtoolskit.com/ancient-unit-converter/ - Category: Converters - Evidence: authored-methodology - Description: Convert classical ancient units: cubit, palm, digit, stadium, talent, and more. See modern equivalents for historical measures. Private, no account. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Converts classical-era units to metric using standard metrological estimates: cubit ≈ 0.4572 m, royal cubit ≈ 0.5236 m, Greek foot ≈ 0.296 m, Roman foot ≈ 0.2963 m, stadium ≈ 185 m, Roman mile ≈ 1,478 m, league ≈ 4,434 m. - Assumptions: The standard academic estimates for each unit are used. | Greek and Roman variants are distinguished where they differ. | Results are historical approximations. - Sources: https://en.wikipedia.org/wiki/Cubit | https://en.wikipedia.org/wiki/Ancient_Roman_units_of_measurement | https://boringtoolskit.com/methodology/ ## Tool: Angle Converter - URL: https://boringtoolskit.com/angle-converter/ - Category: Converters - Evidence: catalogue - Description: Angle converter: degrees, radians, and gradians. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Angular Momentum Calculator - URL: https://boringtoolskit.com/angular-momentum-calculator/ - Category: Physics - Evidence: authored-methodology - Description: Calculate angular momentum of a point mass from mass, velocity, and radius (L = mvr). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Angular momentum (L) = mass × velocity × radius. Units: kg · m²/s. - Assumptions: Mass, velocity, and radius are all in SI units (kg, m/s, m). | The object moves perpendicular to the radius. | Positive values are required for all three inputs. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Annuity Calculator - URL: https://boringtoolskit.com/annuity-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate the future value or payout of an annuity based on deposit, rate, and term. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Future value of an annuity = payment × [((1 + r)^n − 1) ÷ r], where r is the per-period rate and n is the number of periods, for an ordinary annuity (payments at end of period). The tool supports future-value and present-value modes. - Assumptions: Payments are made at the end of each period (ordinary annuity). | A single constant per-period rate is assumed. | Fees, taxes, and surrender charges are not included. - Sources: https://www.investopedia.com/terms/a/annuity.asp | https://boringtoolskit.com/methodology/ ## Tool: Annuity Payout Calculator - URL: https://boringtoolskit.com/annuity-payout-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Annuity payout calculator: monthly income from a lump sum at a fixed rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Appliance Energy Cost Calculator - URL: https://boringtoolskit.com/appliance-energy-cost-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Appliance energy cost calculator: running cost from wattage, usage, and your electricity rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: APR & Effective Interest Calculator - URL: https://boringtoolskit.com/apr-effective-interest-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate payment, fee-adjusted APR, effective annual rate, and total finance cost. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: APR = the rate that makes the loan's present value (principal minus fees) equal to the payment stream. Effective rate = (1 + APR ÷ 12)^12 − 1 for monthly compounding. Fees raise the APR above the stated rate. - Assumptions: The loan is amortized monthly. | Fees are deducted from the loan proceeds. | The loan runs to full term. - Sources: https://en.wikipedia.org/wiki/Annual_percentage_rate | https://boringtoolskit.com/methodology/ ## Tool: APY Calculator - URL: https://boringtoolskit.com/apy-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Convert a nominal annual interest rate and compounding frequency into annual percentage yield. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: APY = (1 + nominal rate ÷ compounds per year)^(compounds per year) − 1. - Assumptions: The nominal rate and compounding frequency remain constant for one year. | No deposits, withdrawals, taxes, or fees occur during the example. | The result is mathematical and not a quoted bank offer. - Sources: https://www.consumerfinance.gov/ask-cfpb/what-is-an-annual-percentage-yield-apy-en-1001/ | https://www.fdic.gov/resources/deposit-insurance/ ## Tool: Aquarium Stocking Calculator - URL: https://boringtoolskit.com/aquarium-stocking-calculator/ - Category: Pets - Evidence: catalogue - Description: Aquarium stocking calculator: fish capacity by tank size. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Arc Length Calculator - URL: https://boringtoolskit.com/arc-length-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Arc length calculator: distance along a circle arc. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Area Converter - URL: https://boringtoolskit.com/area-converter/ - Category: Converters - Evidence: catalogue - Description: Area converter: square feet, acres, hectares, and square meters. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Area Perimeter Calculator - URL: https://boringtoolskit.com/area-perimeter-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Area and perimeter calculator: rectangle, triangle, circle. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Area and perimeter depend on the shape: e.g. rectangle area = length × width, perimeter = 2 × (length + width). - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Arithmetic Sequence Calculator - URL: https://boringtoolskit.com/arithmetic-sequence-calculator/ - Category: School & Education - Evidence: catalogue - Description: Arithmetic sequence calculator: nth term and sum from first term and common difference. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: ASCII Converter - URL: https://boringtoolskit.com/ascii-converter/ - Category: Converters - Evidence: catalogue - Description: ASCII converter: characters to ASCII codes and back. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Aspect Ratio Calculator - URL: https://boringtoolskit.com/aspect-ratio-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the aspect ratio from width and height, or the missing dimension to hit a target ratio like 16:9. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Aspect ratio = width ÷ height reduced to the smallest whole-number ratio using the greatest common divisor (gcd). The tool also reports the decimal value. - Assumptions: Width and height are positive numbers. | The gcd reduction produces the standard form. | The decimal value reflects the exact proportion. - Sources: https://en.wikipedia.org/wiki/Aspect_ratio_(image) | https://boringtoolskit.com/methodology/ ## Tool: Asphalt Calculator - URL: https://boringtoolskit.com/asphalt-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate asphalt volume, weight, waste, and material cost for a rectangular paving area. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Tons = length × width × compacted depth in feet × density ÷ 2,000 × (1 + waste). - Assumptions: Dimensions describe a rectangular area with uniform compacted thickness. | 145 lb/ft³ is only a starting density and is editable. | Base aggregate, tack coat, labor, delivery, and equipment are excluded. - Sources: https://www.fhwa.dot.gov/pavement/asphalt/ | https://www.nist.gov/pml/owm/metric-si/si-units ## Tool: Atmospheric Pressure Calculator - URL: https://boringtoolskit.com/atmospheric-pressure-calculator/ - Category: Geography - Evidence: catalogue - Description: Atmospheric pressure calculator: barometric pressure at elevation (US standard atmosphere). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Attendance Calculator - URL: https://boringtoolskit.com/attendance-calculator/ - Category: School & Education - Evidence: catalogue - Description: Attendance calculator: attendance percentage and days you can still miss to stay above a threshold. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Audio Time Stretch Calculator - URL: https://boringtoolskit.com/audio-time-stretch-calculator/ - Category: Music & Audio - Evidence: authored-methodology - Description: Calculate the new duration when audio playback speed changes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: New duration = original ÷ playback speed. Time change % = (1 ÷ speed − 1) × 100. - Assumptions: Original duration is in seconds and speed must be positive. | Time-stretching changes duration without changing pitch (by design). | The result is a timing estimate, not an encoding guarantee. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Auto Insurance by State - URL: https://boringtoolskit.com/auto-insurance-by-state-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Auto insurance by state: minimum liability limits, no-fault status and coverage tips for every state. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Auto Loan Calculator - URL: https://boringtoolskit.com/auto-loan-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate an auto loan payment, amount financed, total interest, and year-by-year balance. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Auto loan payment = principal × [r × (1+r)^n] ÷ [(1+r)^n − 1], where r = annual rate ÷ 12 and n = term in months. Then total interest and the full amortization schedule are computed over the loan. - Assumptions: A fixed-rate amortizing auto loan. | Sales tax and fees are separate, entered only if you add them. | The payment is principal + interest only, before taxes and registration. - Sources: https://www.investopedia.com/terms/a/auto-loan.asp | https://boringtoolskit.com/methodology/ ## Tool: Average Atomic Mass Calculator - URL: https://boringtoolskit.com/average-atomic-mass-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Calculate average atomic mass from isotope masses and abundances. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Average atomic mass = Σ (isotope mass × relative abundance), with abundances normalized to the fraction version. - Assumptions: Each isotope is entered as mass and abundance (percent or fraction). | Abundances are normalized to a fraction before computing the weighted average. | The sum of abundances should equal the total; unmatched entries are flagged. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Average Return Calculator - URL: https://boringtoolskit.com/average-return-calculator/ - Category: Statistics - Evidence: catalogue - Description: Average return calculator: simple average of yearly returns. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Baby Formula Calculator - URL: https://boringtoolskit.com/baby-formula-calculator/ - Category: Health - Evidence: catalogue - Description: Baby formula calculator: ounces per feeding from baby weight. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Background Text Color Calculator - URL: https://boringtoolskit.com/background-text-color-calculator/ - Category: Colors & Design - Evidence: catalogue - Description: Background text color calculator: choose black or white text on any background color for best contrast. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Backsplash Calculator - URL: https://boringtoolskit.com/backsplash-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Backsplash calculator: material area for a kitchen backsplash after subtracting openings. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Baking Conversions - URL: https://boringtoolskit.com/baking-conversions/ - Category: Converters - Evidence: authored-methodology - Description: Convert cooking and baking measurements between cups, tablespoons, teaspoons, grams, ounces, milliliters, and liters, with ingredient densities. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: To convert within volume (cups, tbsp, tsp, ml, l), multiply by the US ml equivalents. Within mass (g, oz, lb), multiply by the gram equivalents. For mass↔volume, convert using ingredient density in grams per US cup. - Assumptions: US customary cup/tablespoon/teaspoon are used. | Ingredient densities (g/cup) are typical values, not brand-specific. | Conversions are planning estimates for home cooking. - Sources: /methodology/ ## Tool: Baking Ratio Calculator - URL: https://boringtoolskit.com/baking-ratio-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Baking ratio calculator: scale ingredients by baker's percentage or classic ratios (e.g., 3:2:1 pastry). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Balance Transfer Savings Calculator - URL: https://boringtoolskit.com/balance-transfer-savings-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Compare keeping credit-card debt with transferring it to a promotional APR after fees. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Simulates paying off a balance at the current APR vs a 0% (or low) promotional rate: interest paid in each scenario; savings = interest at current APR − interest at promo rate, minus the transfer fee. - Assumptions: Payments are made monthly at the entered amount. | No new purchases are added to the card. | The promo rate applies for the full stated period. - Sources: https://en.wikipedia.org/wiki/Balance_transfer | https://boringtoolskit.com/methodology/ ## Tool: Balloon Payment Calculator - URL: https://boringtoolskit.com/balloon-payment-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Balloon payment calculator: monthly payment plus final balloon balance. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Baluster Spacing Calculator - URL: https://boringtoolskit.com/baluster-spacing-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Baluster spacing calculator: even spacing for railing balusters. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Bandwidth Calculator - URL: https://boringtoolskit.com/bandwidth-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Bandwidth calculator: transfer time for a file size at a given connection speed. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Base64 Encoder Decoder - URL: https://boringtoolskit.com/base64-tool/ - Category: Converters - Evidence: authored-methodology - Description: Encode and decode Base64 text, with local previews for PNG, JPEG, GIF, and WebP image data. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Encoding: each 3 bytes of input become 4 base64 characters (6 bits each) from the A–Za–z0–9+/ alphabet, padded with '=' to a multiple of 4. Decoding reverses the process. - Assumptions: Standard base64 alphabet and padding are used. | The input is valid base64 when decoding. | File handling is supported by the browser. - Sources: https://en.wikipedia.org/wiki/Base64 | https://boringtoolskit.com/methodology/ ## Tool: Baseball OPS Calculator - URL: https://boringtoolskit.com/baseball-ops-calculator/ - Category: Sports - Evidence: catalogue - Description: Baseball OPS calculator: on-base percentage plus slugging percentage. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Baseboard Calculator - URL: https://boringtoolskit.com/baseboard-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Baseboard calculator: linear feet and boards for a room. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Battery Bank Calculator - URL: https://boringtoolskit.com/battery-bank-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Battery bank calculator: amp-hours for an off-grid system. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Battery Life Calculator - URL: https://boringtoolskit.com/battery-life-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Battery life calculator: runtime from battery capacity, voltage, and load power. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Battery Runtime Calculator - URL: https://boringtoolskit.com/battery-runtime-calculator/ - Category: Energy & Electrical - Evidence: authored-methodology - Description: Estimate ideal and adjusted battery runtime from capacity, voltage, load, efficiency, and usable depth. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Nominal energy (Wh) = amp-hours × volts; runtime = nominal energy × usable fraction × efficiency ÷ load watts. - Assumptions: Voltage and load remain constant. | Efficiency and usable capacity are user-entered aggregate factors. | Peukert effects, temperature, degradation, surge loads, and reserve margins are excluded. - Sources: https://www.energy.gov/oe/energy-storage | https://www.sandia.gov/ess-ssl/ ## Tool: Batting Average Calculator - URL: https://boringtoolskit.com/batting-average-calculator/ - Category: Sports - Evidence: catalogue - Description: Batting average calculator: hits divided by at-bats. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Bayes Theorem Calculator - URL: https://boringtoolskit.com/bayes-theorem-calculator/ - Category: Statistics - Evidence: catalogue - Description: Bayes theorem calculator: posterior probability P(A|B) from prior and likelihood rates. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Beam Load Calculator - URL: https://boringtoolskit.com/beam-load-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Beam load calculator: max deflection of a uniformly loaded simple beam (simplified). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Bearing Calculator - URL: https://boringtoolskit.com/bearing-calculator/ - Category: Geography - Evidence: catalogue - Description: Bearing calculator: initial compass bearing between two coordinates. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Beer ABV Calculator - URL: https://boringtoolskit.com/beer-abv-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Beer ABV calculator: alcohol by volume from original and final gravity. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Belt Size Calculator - URL: https://boringtoolskit.com/belt-size-calculator/ - Category: Converters - Evidence: catalogue - Description: Belt size calculator: belt length from waist size. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Betting Odds Converter - URL: https://boringtoolskit.com/betting-odds-converter/ - Category: Gaming - Evidence: catalogue - Description: Betting odds converter: American, decimal, and fractional odds with implied probability. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Big Number Calculator - URL: https://boringtoolskit.com/big-number-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Big number calculator: exact arithmetic on numbers up to 10^30. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Arithmetic on large integers with precision beyond normal floating-point display limits. - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Billing Rate Calculator - URL: https://boringtoolskit.com/billing-rate-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Billing rate calculator: hourly freelance rate from salary. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Binary Calculator - URL: https://boringtoolskit.com/binary-calculator/ - Category: School & Education - Evidence: catalogue - Description: Binary calculator: add, subtract, multiply, and divide binary numbers with decimal results. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Binomial Probability Calculator - URL: https://boringtoolskit.com/binomial-probability-calculator/ - Category: Statistics - Evidence: catalogue - Description: Binomial probability calculator: exact and cumulative probabilities for k successes in n trials. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Biorhythm Calculator - URL: https://boringtoolskit.com/biorhythm-calculator/ - Category: Astrology - Evidence: catalogue - Description: Biorhythm calculator: physical, emotional, and intellectual cycles from birth date to a target date. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Blood Alcohol Content Calculator - URL: https://boringtoolskit.com/blood-alcohol-content-calculator/ - Category: Health - Evidence: catalogue - Description: Blood alcohol content (BAC) calculator: Widmark estimate from drinks, weight, and time \u2014 informational only. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Blood Pressure Category Calculator - URL: https://boringtoolskit.com/blood-pressure-calculator/ - Category: Health - Evidence: catalogue - Description: Blood pressure category calculator: classify a systolic/diastolic reading using the AHA categories. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Blood Sugar Converter - URL: https://boringtoolskit.com/blood-sugar-converter/ - Category: Health - Evidence: catalogue - Description: Blood sugar converter: convert glucose between mg/dL and mmol/L instantly. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Blood Type Inheritance Calculator - URL: https://boringtoolskit.com/blood-type-inheritance-calculator/ - Category: Biology - Evidence: catalogue - Description: Blood type inheritance calculator: possible ABO child blood types from two parents. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: BMI Calculator - URL: https://boringtoolskit.com/bmi-calc/ - Category: Health - Evidence: authored-methodology - Description: Calculate BMI quickly and privately in your browser. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: BMI = weight (kg) ÷ height (m)², or weight (lb) ÷ height (in)² × 703. Categories: <18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30+ obese. - Assumptions: Height and weight are entered accurately. | WHO category thresholds apply. | The result is used as a screening tool. - Sources: https://en.wikipedia.org/wiki/Body_mass_index | https://boringtoolskit.com/methodology/ ## Tool: BMR & TDEE Calculator - URL: https://boringtoolskit.com/bmr-tdee-calculator/ - Category: Health - Evidence: authored-methodology - Description: Estimate adult BMR and TDEE from the Mifflin-St Jeor equation and an explicit activity multiplier. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Mifflin-St Jeor BMR: male = 10×weight(kg) + 6.25×height(cm) − 5×age + 5; female = 10×weight(kg) + 6.25×height(cm) − 5×age − 161. TDEE = BMR × activity multiplier: 1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 very active, 1.9 extra active. - Assumptions: The Mifflin-St Jeor equation applies (adults 18–100). | The chosen activity multiplier reflects the user's lifestyle. | Results are estimates for planning, not medical prescriptions. - Sources: https://www.mdcalc.com/calc/56/mifflin-st-jeor-equation-calorie-deficit | https://boringtoolskit.com/methodology/ ## Tool: Board Foot Calculator - URL: https://boringtoolskit.com/board-foot-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Calculate lumber volume in board feet from thickness, width, length, and quantity. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Board feet = thickness (in) × width (in) × length (ft) ÷ 12. One board foot = 1 inch × 1 foot × 1 foot (144 in³). - Assumptions: Nominal or actual dimensions are entered consistently. | One board foot = 144 in³. | Quantity multiplies the per-piece volume. - Sources: https://en.wikipedia.org/wiki/Board_foot | https://boringtoolskit.com/methodology/ ## Tool: Boat Loan Calculator - URL: https://boringtoolskit.com/boat-loan-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Boat loan calculator: boat and RV loan payment. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Body Fat Estimate Calculator - URL: https://boringtoolskit.com/body-fat-calculator/ - Category: Health - Evidence: authored-methodology - Description: Estimate adult body-fat percentage with the U.S. Navy circumference method and clear limitations. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Male: 86.010×log10(waist−neck) − 70.041×log10(height) + 36.76. Female: 163.205×log10(waist+hip−neck) − 97.684×log10(height) − 78.387. Measurements in inches. - Assumptions: The named U.S. Navy circumference equations are used with inch measurements. | Measurements must follow a consistent tape-placement protocol. | The estimate is not a clinical diagnosis and may be inaccurate for individuals outside the source population. - Sources: https://www.mynavyhr.navy.mil/Portals/55/Support/Culture%20Resilience/Physical/Guide%204-%20Body%20Composition%20Assessment%20(BCA)%20(MAR%202023).pdf | https://www.cdc.gov/bmi/adult-calculator/bmi-categories.html ## Tool: Body Surface Area Calculator - URL: https://boringtoolskit.com/body-surface-area-calculator/ - Category: Health - Evidence: catalogue - Description: Body surface area calculator: Mosteller formula from height and weight. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Bond Calculator - URL: https://boringtoolskit.com/bond-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate a bond's current yield and price from coupon rate, face value, and market rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Bond price = Σ (annual coupon ÷ (1 + market rate)^t) for each year t, plus face value ÷ (1 + market rate)^years. The annual coupon is the face value × coupon rate; current yield = annual coupon ÷ price. - Assumptions: Coupons are paid annually. | A single flat market rate is used for discounting. | Credit risk, taxes, and call features are not modeled. - Sources: https://www.investopedia.com/terms/b/bond.asp | https://boringtoolskit.com/methodology/ ## Tool: Bonus Percentage Calculator - URL: https://boringtoolskit.com/bonus-percentage-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Bonus percentage calculator: bonus from salary and percent. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Bowling Handicap Calculator - URL: https://boringtoolskit.com/bowling-handicap-calculator/ - Category: Sports - Evidence: catalogue - Description: Bowling handicap calculator: league handicap from average. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: BPM to Delay Time Calculator - URL: https://boringtoolskit.com/bpm-to-delay-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Convert BPM (beats per minute) into delay and reverb timing in milliseconds for quarter, eighth, and dotted eighth notes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Delay time = 60,000 ÷ BPM per beat. Note values divide that: quarter = 1 beat, eighth = ½, dotted eighth = ¾, sixteenth = ¼, triplet = ⅓. - Assumptions: The BPM is accurate for the song. | Standard note divisions apply. | The delay is set in milliseconds. - Sources: https://en.wikipedia.org/wiki/Tempo | https://boringtoolskit.com/methodology/ ## Tool: BPM to MS Calculator - URL: https://boringtoolskit.com/bpm-to-ms-calculator/ - Category: Music & Audio - Evidence: authored-methodology - Description: Convert beats per minute to milliseconds for note divisions used in music production. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Quarter-note duration (ms) = 60,000 ÷ BPM. Eighth = quarter ÷ 2; dotted eighth = quarter × 0.75; sixteenth = quarter ÷ 4; triplet eighth = quarter ÷ 3; bar (4 beats) = quarter × 4. - Assumptions: BPM must be positive. | Times are note durations at the given tempo, not actual audio. | Dotted and triplet values follow the standard subdivisions. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Bra Size Calculator - URL: https://boringtoolskit.com/bra-size-calculator/ - Category: Health - Evidence: catalogue - Description: Bra size calculator: band and cup size from underbust and bust measurements. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Break-Even Ratio Calculator - URL: https://boringtoolskit.com/break-even-ratio-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate the break-even ratio for a rental property. See what share of income is consumed before cash flow turns positive. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Break-even ratio = (annual debt service + annual operating expenses) ÷ annual gross income × 100. A ratio under 100% means the property's income covers its debt and operating costs, with margin left over. - Assumptions: Break-even ratio uses gross income, before vacancy. | Debt service is the full annual mortgage payment (P&I). | Operating expenses exclude debt service and income tax. - Sources: https://www.investopedia.com/terms/b/break-even-ratio.asp | https://boringtoolskit.com/methodology/ ## Tool: Break-Even Units Calculator - URL: https://boringtoolskit.com/break-even-units-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Find break-even units instantly: calculate contribution margin, required revenue, and units needed to cover costs and target profit. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Break-even units = fixed costs ÷ (price − variable cost per unit). With a target profit: (fixed costs + target profit) ÷ contribution margin. Contribution margin = price − variable cost. - Assumptions: Fixed and variable costs are accurately separated. | The unit price is constant. | All units produced are sold at that price. - Sources: https://en.wikipedia.org/wiki/Break-even_(economics) | https://boringtoolskit.com/methodology/ ## Tool: Breaker Size Calculator - URL: https://boringtoolskit.com/breaker-size-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Breaker size calculator: breaker amps from load watts. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Brick Calculator - URL: https://boringtoolskit.com/brick-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Brick calculator: estimate bricks for a wall from dimensions, brick size, and mortar joints. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: BTU Calculator - URL: https://boringtoolskit.com/btu-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate the BTUs needed to heat or cool a room based on size and conditions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Base BTU = room volume (L × W × H) × 1.5. Additions: sun exposure = sun% × base; people = people × 500 BTU. Total = base + sun adjustment + people adjustment. The result is the cooling capacity in BTU/hour. - Assumptions: About 1.5 BTU per cubic foot of room volume. | Each occupant adds about 500 BTU/hr. | Average insulation and window conditions. - Sources: https://en.wikipedia.org/wiki/British_thermal_unit | https://boringtoolskit.com/methodology/ ## Tool: Budget Planner Calculator - URL: https://boringtoolskit.com/budget-planner-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Budget planner calculator: monthly income minus fixed costs and spending. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Buffer Solution Calculator - URL: https://boringtoolskit.com/buffer-solution-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Calculate buffer pH using the Henderson-Hasselbalch equation. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Henderson–Hasselbalch: pH = pKa + log₁₀([conjugate base] ÷ [weak acid]). - Assumptions: pKa and the concentrations of the weak acid and conjugate base are entered. | The approximation holds when the acid and base concentrations are within the buffering range. | The calculation assumes ideal dilute aqueous solution at 25°C. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Business Days Calculator - URL: https://boringtoolskit.com/business-days-calculator/ - Category: Time & Work - Evidence: authored-methodology - Description: Count weekdays between two dates with an optional number of excluded holidays. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Counts the weekdays (Monday–Friday) between a start and end date, inclusive of both. - Assumptions: Business days = Monday–Friday. | Both dates are included in the count. | Holidays are excluded by the user separately. - Sources: https://en.wikipedia.org/wiki/Business_day | https://boringtoolskit.com/methodology/ ## Tool: Business Loan Calculator - URL: https://boringtoolskit.com/business-loan-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Business loan calculator: SBA-style loan payment. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Business Name Generator - URL: https://boringtoolskit.com/business-name-generator/ - Category: Generators - Evidence: authored-methodology - Description: Generate business and brand name ideas from your industry and style — privacy-clean, no sign-up. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: The generator combines your industry with a style-specific prefix and a curated suffix list. Each pass picks random combinations and de-duplicates them, returning the requested number of unique candidates. - Assumptions: Generated output is a starting point, not final professional copy. | Nothing you type leaves your browser. | Results vary on each run because selection is random. - Sources: /methodology/ ## Tool: C1V1 = C2V2 Calculator - URL: https://boringtoolskit.com/c1v1-c2v2-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Solve for concentration or volume in C1V1 = C2V2 dilution equations. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: C₁V₁ = C₂V₂; solve for whichever of the four variables (C₁, V₁, C₂, V₂) is left blank. - Assumptions: Provide any three values and leave exactly one blank. | Concentration and volume units must be consistent. | The relationship assumes the moles of solute are conserved through dilution. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Caffeine Half-Life Calculator - URL: https://boringtoolskit.com/caffeine-half-life-calculator/ - Category: Health - Evidence: catalogue - Description: Caffeine half-life calculator: how much caffeine remains in your system over time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Caffeine Intake Calculator - URL: https://boringtoolskit.com/caffeine-intake-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Caffeine intake calculator: total daily caffeine from coffee, tea, energy drinks, and soda. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: CAGR Calculator - URL: https://boringtoolskit.com/cagr-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate compound annual growth rate from starting value, ending value, and elapsed years. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: CAGR = (ending value ÷ starting value)^(1 ÷ years) − 1. - Assumptions: No contributions or withdrawals occur between the endpoints. | The time period is measured in years. | CAGR is a smoothed historical rate, not a forecast. - Sources: https://www.investor.gov/introduction-investing/investing-basics/glossary/annual-return | https://www.sec.gov/resources-for-investors/investor-alerts-bulletins/investor-bulletin-performance-claims ## Tool: Calorie Calculator - URL: https://boringtoolskit.com/calorie-calc/ - Category: Health - Evidence: authored-methodology - Description: Estimate daily calories and macros from simple inputs. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Estimates daily calories with the Mifflin-St Jeor equation: BMR = 10×kg + 6.25×cm − 5×age + 5 (male) or −161 (female), then multiplied by an activity factor (1.2–1.9). - Assumptions: The Mifflin-St Jeor equation applies. | The activity factor is realistic. | Weight-change goals use standard deficit/surplus ranges. - Sources: https://en.wikipedia.org/wiki/Basal_metabolic_rate | https://boringtoolskit.com/methodology/ ## Tool: Calorie Deficit Calculator - URL: https://boringtoolskit.com/calorie-deficit-calculator/ - Category: Health - Evidence: catalogue - Description: Calorie deficit calculator: weight-loss timeline from daily deficit and target pounds. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Calorie Target Calculator - URL: https://boringtoolskit.com/calorie-target-calculator/ - Category: Health - Evidence: catalogue - Description: Calorie target calculator: maintenance, deficit, and surplus targets from weight, height, age, and activity. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Calories Burned Calculator - URL: https://boringtoolskit.com/calories-burned-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate calories burned during exercise using MET values and body weight. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Calories burned = MET × 3.5 × weight (kg) ÷ 200 × minutes. The MET value is the activity's metabolic equivalent from the Compendium of Physical Activities (e.g., ~3.5 walking, ~4.3 brisk walking, ~9.8 running at 6 mph). Weight in lb is converted: kg = lb × 0.453592. - Assumptions: The MET value reflects the user's actual effort level. | The formula is the standard ACSM estimation. | Individual metabolic differences are not modeled. - Sources: https://pacompendium.com/ | https://boringtoolskit.com/methodology/ ## Tool: Candy Temperature Calculator - URL: https://boringtoolskit.com/candy-temperature-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Candy temperature calculator: sugar stages from temperature. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Cap Rate Calculator - URL: https://boringtoolskit.com/cap-rate-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate the capitalization rate on a rental property. Enter property value and net operating income (NOI) for unlevered yield. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Capitalization rate = net operating income ÷ property value × 100. It is an unlevered yield: operating income (before debt service) divided by the full purchase price or current value. - Assumptions: NOI excludes debt service, income tax, and one-time capital expenditures. | Property value can be a recent appraisal, the purchase price, or a current market estimate — use the same basis when comparing. | Operating expenses shown are recurring annual costs (taxes, insurance, maintenance, management). - Sources: https://www.investopedia.com/terms/c/cap-rate.asp | https://boringtoolskit.com/methodology/ ## Tool: Capacitance Calculator - URL: https://boringtoolskit.com/capacitance-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Capacitance calculator: capacitance from stored energy and voltage. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Capital Gains Calculator - URL: https://boringtoolskit.com/capital-gains-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Capital gains calculator: tax on an asset sale from sell price, cost basis, and your capital gains rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Car Insurance Estimator - URL: https://boringtoolskit.com/car-insurance-estimator/ - Category: Vehicles - Evidence: catalogue - Description: Car insurance estimator: rough annual premium from vehicle value, driver age, and record. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Car Loan Refinance Calculator - URL: https://boringtoolskit.com/car-loan-refinance-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Car loan refinance calculator: monthly savings from refinancing a car loan. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Real Estate Cash Flow Calculator - URL: https://boringtoolskit.com/cash-flow-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate your monthly real estate cash flow. Enter rental income and all operating costs to see positive or negative cash flow. Private. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Monthly cash flow = gross income (rent + other) − total monthly expenses (mortgage payment + taxes + insurance + maintenance + other operating costs). Positive cash flow means the property earns more than it costs to hold each month. - Assumptions: Expenses are entered as recurring monthly amounts. | Mortgage payment is the total P&I monthly cost. | Maintenance and 'other' are estimates — actual costs may be higher. - Sources: https://www.consumerfinance.gov/owning-a-home/ | https://boringtoolskit.com/methodology/ ## Tool: Cash-Flow Runway Calculator - URL: https://boringtoolskit.com/cash-flow-runway-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Model monthly cash runway, depletion month, lowest cash, and operating break-even from editable growth assumptions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Monthly burn = monthly expenses − monthly revenue. Runway = starting cash ÷ burn. The tool also projects depletion month and break-even month with optional revenue/expense growth. - Assumptions: Monthly revenue and expenses are steady (or follow the entered growth). | The horizon is up to 120 months. | No funding events or irregular expenses are modeled. - Sources: https://en.wikipedia.org/wiki/Cash_flow | https://boringtoolskit.com/methodology/ ## Tool: Cash-on-Cash Return Calculator - URL: https://boringtoolskit.com/cash-on-cash-return-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate cash-on-cash return on a rental property. Enter annual cash flow and total cash invested for yield on the cash you put in. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Cash-on-cash return = annual pre-tax cash flow ÷ total cash invested × 100. It measures the yield on the cash you actually put in (down payment + closing costs), giving a financing-aware view of return. - Assumptions: Annual cash flow is pre-tax and before any depreciation benefit. | Total cash invested includes down payment and closing costs but not loan proceeds. | The result is a single-year snapshot, not a lifetime return. - Sources: https://www.investopedia.com/terms/c/cashoncashreturn.asp | https://boringtoolskit.com/methodology/ ## Tool: Cat Age Calculator - URL: https://boringtoolskit.com/cat-age-calculator/ - Category: Pets - Evidence: catalogue - Description: Cat age calculator: cat years to human years. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Cat Food Calculator - URL: https://boringtoolskit.com/cat-food-calculator/ - Category: Pets - Evidence: catalogue - Description: Cat food calculator: daily calories and cups from cat weight. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Cat Litter Calculator - URL: https://boringtoolskit.com/cat-litter-calculator/ - Category: Pets - Evidence: catalogue - Description: Cat litter calculator: litter needed for a multi-cat home. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: CD Calculator - URL: https://boringtoolskit.com/cd-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the maturity value and interest earned on a Certificate of Deposit over its term. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Maturity value = deposit × (1 + APY ÷ compounds)^(compounds × years); interest earned = maturity value − deposit. The APY is compounded at the selected frequency over the CD term. - Assumptions: The APY stays constant for the full term. | Interest is compounded at the selected frequency. | No withdrawals are made before maturity. - Sources: https://www.investopedia.com/terms/c/certificateofdeposit.asp | https://boringtoolskit.com/methodology/ ## Tool: Ceiling Fan Size Calculator - URL: https://boringtoolskit.com/ceiling-fan-size-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Ceiling fan size calculator: blade span by room size. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Ceiling Tile Calculator - URL: https://boringtoolskit.com/ceiling-tile-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Ceiling tile calculator: 2x2 drop-ceiling tiles for a room. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Chair Rail Calculator - URL: https://boringtoolskit.com/chair-rail-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Chair rail calculator: classic height from ceiling height. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Chargaff Rule Calculator - URL: https://boringtoolskit.com/chargaff-rule-calculator/ - Category: Biology - Evidence: catalogue - Description: Chargaff rule calculator: predict T, G, and C percentages from adenine percentage in double-stranded DNA. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Chess Elo Calculator - URL: https://boringtoolskit.com/chess-elo-calculator/ - Category: Gaming - Evidence: catalogue - Description: Chess Elo calculator: expected score and new rating after a game using the standard Elo formula. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Chi-Square Goodness of Fit Calculator - URL: https://boringtoolskit.com/chi-square-calculator/ - Category: Statistics - Evidence: catalogue - Description: Chi-square calculator: goodness-of-fit test statistic from observed vs expected counts. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Child Care Cost Calculator - URL: https://boringtoolskit.com/child-care-cost-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Child care cost calculator: annual cost of daycare or nanny care. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Children Size Converter - URL: https://boringtoolskit.com/children-size-converter/ - Category: Converters - Evidence: catalogue - Description: Children size converter: US to EU kids clothing sizes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Chinese Zodiac Calculator - URL: https://boringtoolskit.com/chinese-zodiac-calculator/ - Category: Astrology - Evidence: catalogue - Description: Chinese zodiac calculator: animal sign and element from birth year, with lunar-new-year caveat. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Cholesterol Ratio Calculator - URL: https://boringtoolskit.com/cholesterol-ratio-calculator/ - Category: Health - Evidence: catalogue - Description: Cholesterol ratio calculator: total-to-HDL and LDL-to-HDL ratios from a lipid panel. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Chord Progression Generator - URL: https://boringtoolskit.com/chord-progression-generator/ - Category: Music & Audio - Evidence: catalogue - Description: Chord progression generator: common diatonic progressions in any key, computed locally. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Circle Area Calculator - URL: https://boringtoolskit.com/circle-area-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Circle area calculator: area and circumference from radius. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Area = π × r², where r is the radius. Circumference = 2 × π × r. - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Circle Calculator - URL: https://boringtoolskit.com/circle-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Find a circle's area, circumference, diameter, or radius from any one value. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: From radius r: diameter d = 2r, circumference c = 2πr, area A = πr². The tool also derives r from a known diameter (r = d/2), circumference (r = c/(2π)), or area (r = √(A/π)). - Assumptions: The shape is a perfect circle. | π is approximated to standard precision. | The input value is positive. - Sources: https://www.mathsisfun.com/geometry/circle.html | https://boringtoolskit.com/methodology/ ## Tool: Citation Formatter - URL: https://boringtoolskit.com/citation-formatter/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Format a book, website, or article into APA and MLA citations from author, title, publisher, year, and URL. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Formats source details into APA and MLA citations: author, year, title, publisher/venue, and URL, following each style's punctuation and order rules. - Assumptions: The entered metadata is accurate. | The source is a common type (book, article, webpage). | The style guide version matches the formatter. - Sources: https://en.wikipedia.org/wiki/Citation | https://boringtoolskit.com/methodology/ ## Tool: Closing Cost Calculator - URL: https://boringtoolskit.com/closing-cost-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate closing costs on a home purchase. Enter price, down payment, and typical fee percentages for an itemized total. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Total closing costs = down payment + lender fees + title fees + government fees + other costs. Each component (lender, title, government, other) is a user-entered dollar or percentage figure added together. - Assumptions: Closing costs exclude the down payment itself. | Fee figures are user-entered estimates — actuals vary by lender and location. | Transfer taxes and title costs differ by state and county. - Sources: https://www.investopedia.com/terms/c/closing-costs.asp | https://boringtoolskit.com/methodology/ ## Tool: Clothing Size Converter - URL: https://boringtoolskit.com/clothing-size-converter/ - Category: Travel - Evidence: catalogue - Description: Clothing size converter: international clothing size conversion (US, UK, EU). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Coefficient of Variation Calculator - URL: https://boringtoolskit.com/coefficient-of-variation-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the coefficient of variation (relative standard deviation). Enter the mean and standard deviation to compare variability across data sets. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Coefficient of variation (CV) = (standard deviation ÷ mean) × 100. A CV below ~15% is often considered low relative spread. - Assumptions: Mean must be non-zero to compute CV. | CV is a relative (unit-free) measure of dispersion, useful for comparing data sets with different means. | Lower CV suggests lower variability relative to the mean. - Sources: https://www.itl.nist.gov/div898/handbook/ | https://boringtoolskit.com/methodology/ ## Tool: Coffee Cost Calculator - URL: https://boringtoolskit.com/coffee-cost-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Coffee cost calculator: what your daily coffee habit really costs per year. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Coffee Ratio Calculator - URL: https://boringtoolskit.com/coffee-ratio-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Coffee ratio calculator: grams of coffee for water and ratio. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Cohen's D Calculator - URL: https://boringtoolskit.com/cohens-d-calculator/ - Category: Statistics - Evidence: catalogue - Description: Cohen's d calculator: effect size between two groups. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Coin Flip Tool - URL: https://boringtoolskit.com/coin-flip/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Flip one or up to 100 coins locally with secure browser randomness, counts, percentages, streaks, and sequence. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Simulates fair (or weighted) coin flips, counting heads and tails. A fair coin gives each outcome a 50% probability per flip. - Assumptions: Each flip is independent. | The default is a fair 50/50 coin. | Results are generated with a uniform RNG. - Sources: https://en.wikipedia.org/wiki/Coin_flipping | https://boringtoolskit.com/methodology/ ## Tool: College Cost Calculator - URL: https://boringtoolskit.com/college-cost-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: College cost calculator: four-year total cost with tuition inflation. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Color Difference Calculator - URL: https://boringtoolskit.com/color-difference-calculator/ - Category: Colors & Design - Evidence: catalogue - Description: Color difference calculator: CIE76 delta E between two hex colors for design QA. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Color Gradient Calculator - URL: https://boringtoolskit.com/color-gradient-calculator/ - Category: Colors & Design - Evidence: catalogue - Description: Color gradient calculator: interpolate between two hex colors and get a mid-tone blend. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Color Mixer Calculator - URL: https://boringtoolskit.com/color-mixer-calculator/ - Category: Colors & Design - Evidence: catalogue - Description: Color mixer calculator: blend two hex colors by any percentage to predict a paint or digital mix. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Color Palette Generator - URL: https://boringtoolskit.com/color-palette-generator/ - Category: Colors & Design - Evidence: catalogue - Description: Color palette generator: harmonic color schemes from a base hex color, computed locally. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Color Picker - URL: https://boringtoolskit.com/color-picker/ - Category: Text & Developer Tools - Evidence: authored-methodology - Description: Choose a color, inspect HEX, RGB, HSL, HSV, and CMYK values, and copy formats locally. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Converts between color models: hex (#RRGGBB) ↔ RGB ↔ HSL, with HSV. RGB values are 0–255; HSL hue is 0–360° with saturation and lightness as percentages. - Assumptions: The color is for screen use (RGB family). | Hex input uses the standard #RRGGBB form. | Device calibration is outside the tool's scope. - Sources: https://en.wikipedia.org/wiki/HSL_and_HSV | https://boringtoolskit.com/methodology/ ## Tool: Color Tint Shade Calculator - URL: https://boringtoolskit.com/color-tint-shade-calculator/ - Category: Colors & Design - Evidence: catalogue - Description: Color tint shade calculator: lighten and darken a hex color in steps, generated locally. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Combinations Calculator (nCr) - URL: https://boringtoolskit.com/combinations-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the number of combinations (nCr) of choosing r items from n, with the formula explained. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: nCr = n! ÷ (r! × (n − r)!). The calculator evaluates it multiplicatively as c = c × (n − r + i) ÷ i for i = 1..r, which keeps intermediate values smaller than a raw factorial. - Assumptions: r must be between 0 and n, and n at least 1. | Order does not matter (unordered selection). | Result is rounded to the nearest integer. - Sources: /methodology/ ## Tool: Combinations and Permutations Calculator - URL: https://boringtoolskit.com/combinations-permutations-calculator/ - Category: Statistics - Evidence: catalogue - Description: Combinations and permutations calculator: count arrangements and selections with or without repetition. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Commission Calculator - URL: https://boringtoolskit.com/commission-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Calculate commission on sales using flat, threshold, or progressive tier rates. See total commission and a clear tier commission breakdown. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Flat: commission = sales × rate. Threshold: rate applies only to sales above a floor. Tiered: multiple rates apply to brackets (e.g., 5% to $10k, 7% above). The tool reports commission, eligible sales, and a breakdown. - Assumptions: Tiers apply marginally (each bracket at its own rate). | Sales are net of returns. | No draw, bonus, or chargeback adjustments. - Sources: https://en.wikipedia.org/wiki/Commission_(remuneration) | https://boringtoolskit.com/methodology/ ## Tool: Commute Cost Calculator - URL: https://boringtoolskit.com/commute-cost-calculator/ - Category: Travel - Evidence: catalogue - Description: Commute cost calculator: monthly driving cost and time for a round trip. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Complementary Color Finder - URL: https://boringtoolskit.com/complementary-color-finder/ - Category: Colors & Design - Evidence: catalogue - Description: Complementary color finder: the exact opposite hue on the color wheel for any hex color. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Complex Number Calculator - URL: https://boringtoolskit.com/complex-number-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Complex number calculator: add, subtract, multiply complex numbers. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Compound Interest Calculator - URL: https://boringtoolskit.com/compound-interest/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate compound interest with recurring contributions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Future value = principal × (1 + rate/n)^(n×years), where n is the compounding frequency per year. Interest is earned on the principal AND on previously earned interest — the source of compounding growth. - Assumptions: A constant annual return and fixed compounding frequency. | No additional contributions, taxes, or fees. | The projection is a mathematical estimate, not a guarantee. - Sources: https://www.investopedia.com/terms/c/compoundinterest.asp | https://boringtoolskit.com/methodology/ ## Tool: Conception Calculator - URL: https://boringtoolskit.com/conception-calculator/ - Category: Health - Evidence: catalogue - Description: Conception calculator: conception date and fertility window from due date. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Concrete Calculator - URL: https://boringtoolskit.com/concrete-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate concrete volume, weight, and bags for a slab. Includes a built-in waste factor so you order enough the first time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Volume = length × width × (depth in inches ÷ 12) = cubic feet; cubic yards = cubic feet ÷ 27. Order volume = cubic yards × (1 + waste%). - Assumptions: The pour is a rectangular slab. | Depth is uniform. | Waste covers subgrade variation and spillage. - Sources: https://www.quikrete.com/calculator/main.asp | https://boringtoolskit.com/methodology/ ## Tool: Concrete Cost Per Square Foot Calculator - URL: https://boringtoolskit.com/concrete-cost-per-square-foot/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate concrete cost per square foot and total for a slab from your own rate and waste. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Total slab cost = area × rate per sq ft × (1 + waste%). The rate per square foot bundles material, labor, and finishing for the selected thickness. - Assumptions: The rate per square foot is user-entered from local pricing. | Waste covers spillage and over-excavation. | Excavation, sub-base, and permits are not included. - Sources: https://www.quikrete.com/calculator/main.asp | https://boringtoolskit.com/methodology/ ## Tool: Conditional Probability Calculator - URL: https://boringtoolskit.com/conditional-probability-calculator/ - Category: Statistics - Evidence: catalogue - Description: Conditional probability calculator: P(A|B) from the intersection. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Cone Volume Calculator - URL: https://boringtoolskit.com/cone-volume-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Cone volume calculator: volume from radius and height. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Volume = (1/3) × π × r² × h, where r is base radius and h is height. - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Confidence Interval Calculator - URL: https://boringtoolskit.com/confidence-interval-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Compute a confidence interval for a sample mean given size, std dev, and confidence level. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Confidence interval = mean ± z* × (standard deviation ÷ √n). The tool uses z* = 1.645 for 90%, 1.96 for 95%, and 2.576 for 99% confidence, with standard error = sd ÷ √n and margin of error = z* × standard error. - Assumptions: The sample is drawn randomly and independently. | The sampling distribution is roughly normal (large-sample z approach). | The population standard deviation is approximated by the sample's. - Sources: https://www.itl.nist.gov/div898/handbook/eda/section3/eda352.htm | https://boringtoolskit.com/methodology/ ## Tool: Contrast Ratio Calculator (WCAG) - URL: https://boringtoolskit.com/contrast-ratio-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Check the contrast ratio between two colors and see whether it passes WCAG AA and AAA for normal and large text. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: WCAG contrast ratio = (L1 + 0.05) ÷ (L2 + 0.05), where L is relative luminance: 0.2126R + 0.7152G + 0.0722B with linearized channels. - Assumptions: Hex colors are entered correctly. | The WCAG 2.x luminance formula applies. | Text size determines the applicable threshold. - Sources: https://en.wikipedia.org/wiki/Relative_luminance | https://boringtoolskit.com/methodology/ ## Tool: Cooking Time Calculator - URL: https://boringtoolskit.com/cooking-time-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Cooking time calculator: estimate oven or roasting time from weight and minutes-per-pound method. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Coordinate Converter - URL: https://boringtoolskit.com/coordinate-converter/ - Category: Geography - Evidence: catalogue - Description: Coordinate converter: convert between decimal degrees and degrees/minutes/seconds. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Correlation Coefficient Calculator - URL: https://boringtoolskit.com/correlation-coefficient-calculator/ - Category: Statistics - Evidence: catalogue - Description: Correlation coefficient calculator: Pearson r between two paired data sets, with strength and direction. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Countdown Timer - URL: https://boringtoolskit.com/countdown-timer/ - Category: Time & Work - Evidence: authored-methodology - Description: Set a countdown and get notified when time is up. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Counts down from a set minutes/seconds value to zero, updating every second. The tool plays an alert and shows a done state when time expires. - Assumptions: The tab stays open and visible during the countdown. | The countdown is minutes-scale. | The alert is audible in the browser. - Sources: https://en.wikipedia.org/wiki/Timer | https://boringtoolskit.com/methodology/ ## Tool: Countertop Calculator - URL: https://boringtoolskit.com/countertop-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Countertop calculator: countertop cost from square feet. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Country Facts and Comparison - URL: https://boringtoolskit.com/country-facts/ - Category: Text & Developer Tools - Evidence: authored-methodology - Description: Browse country facts , capital, region, currency, languages, and flags , and compare two countries side by side. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: A static reference dataset of countries: name, code, capital, region, currency, languages, population, and area — formatted for comparison. - Assumptions: Reference values are approximations. | Currency codes use ISO 4217. | Languages list the primary official languages. - Sources: https://en.wikipedia.org/wiki/Country | https://boringtoolskit.com/methodology/ ## Tool: CPM Calculator - URL: https://boringtoolskit.com/cpm-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Calculate CPM, campaign cost, impressions, or estimated ad revenue from pageviews and RPM. Any two values solve the third. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: CPM = cost ÷ impressions × 1,000. It's the price of 1,000 ad impressions — the standard metric for display and video campaigns. - Assumptions: Impressions are delivered as reported. | Spend is the full campaign cost. | Comparisons use the same format and targeting. - Sources: https://en.wikipedia.org/wiki/Cost_per_impression | https://boringtoolskit.com/methodology/ ## Tool: Credit Card Payoff Calculator - URL: https://boringtoolskit.com/credit-card-payoff-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate credit-card payoff time and interest from balance, APR, and monthly payment. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Simulates the balance month by month: balance += balance × APR ÷ 12 − payment. The tool reports months to payoff and total interest. Payment must exceed the first month's interest or it never pays off. - Assumptions: No new purchases are added. | The payment stays constant. | The APR is fixed. - Sources: https://en.wikipedia.org/wiki/Credit_card | https://boringtoolskit.com/methodology/ ## Tool: Credit Utilization Calculator - URL: https://boringtoolskit.com/credit-utilization-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Credit utilization calculator: credit score impact from balances vs limits. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Crochet Hook Converter - URL: https://boringtoolskit.com/crochet-hook-converter/ - Category: Converters - Evidence: catalogue - Description: Crochet hook converter: US letters to millimeters. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Cross Product Calculator - URL: https://boringtoolskit.com/cross-product-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Cross product calculator: vector product of two 3D vectors. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Crown Molding Calculator - URL: https://boringtoolskit.com/crown-molding-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Crown molding calculator: linear feet and boards needed for a room. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Crypto Profit Calculator - URL: https://boringtoolskit.com/crypto-calc/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate crypto profit and ROI with fees. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Profit = (sell price − buy price) × amount − buy fees − sell fees. ROI = profit ÷ (buy price × amount + buy fee) × 100. - Assumptions: Simple spot trades with no leverage. | Fees are entered explicitly. | No staking, airdrops, or other income is modeled. - Sources: https://en.wikipedia.org/wiki/Cryptocurrency | https://boringtoolskit.com/methodology/ ## Tool: CSV to JSON Converter - URL: https://boringtoolskit.com/csv-to-json/ - Category: Converters - Evidence: authored-methodology - Description: Convert CSV to JSON instantly — paste comma or tab-separated data and get a clean JSON array of objects. Free, private, runs in your browser. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Parses CSV rows: the first row becomes object keys; each subsequent row becomes an object mapping those keys to the row's values. Output is a JSON array of objects. - Assumptions: The CSV has a header row. | Fields with commas are properly quoted. | Encoding is UTF-8. - Sources: https://en.wikipedia.org/wiki/Comma-separated_values | https://boringtoolskit.com/methodology/ ## Tool: Currency Converter - URL: https://boringtoolskit.com/currency-conv/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Free currency converter between 15+ major currencies — USD, EUR, GBP, JPY and more. Quick estimates with reference rates, no signup. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Converts an amount between major currencies using reference exchange rates: converted = amount × (rate from → to). - Assumptions: Reference rates are close to current mid-market. | No transaction fees are modeled. | The currencies are in the supported set. - Sources: https://en.wikipedia.org/wiki/Exchange_rate | https://boringtoolskit.com/methodology/ ## Tool: Curtain Length Calculator - URL: https://boringtoolskit.com/curtain-length-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Curtain length calculator: panel length from window height. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Customer Lifetime Value Calculator - URL: https://boringtoolskit.com/customer-lifetime-value-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Calculate gross-contribution customer lifetime value, implied lifetime, and a planning CAC ceiling from your inputs and LTV:CAC target. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Annual gross contribution = average order value × purchases per year × gross margin %. Customer lifetime = 1 ÷ annual churn rate. LTV = annual contribution × lifetime. Max acquisition cost = LTV ÷ target LTV:CAC ratio. - Assumptions: Order value, frequency, and margin are stable. | Churn is constant over the customer's life. | No referral or expansion revenue is modeled. - Sources: https://en.wikipedia.org/wiki/Customer_lifetime_value | https://boringtoolskit.com/methodology/ ## Tool: Cycling Calories Calculator - URL: https://boringtoolskit.com/cycling-calories-calculator/ - Category: Health - Evidence: catalogue - Description: Cycling calories calculator: calories burned cycling by weight and time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Cycling Power to Weight Calculator - URL: https://boringtoolskit.com/cycling-power-to-weight-calculator/ - Category: Sports - Evidence: catalogue - Description: Cycling power-to-weight calculator: watts per kilogram for climbs and race grading. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Cylinder Volume Calculator - URL: https://boringtoolskit.com/cylinder-volume-calculator/ - Category: Physics - Evidence: catalogue - Description: Cylinder volume calculator: volume of a cylinder from radius and height. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Dad Joke Generator - URL: https://boringtoolskit.com/dad-joke-generator/ - Category: Generators - Evidence: authored-methodology - Description: Generate groan-worthy dad jokes and one-liners by category — instantly, right in your browser. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Jokes are drawn from category-specific pools and shuffled randomly. No external request is made — everything runs in your browser. - Assumptions: Generated output is a starting point, not final professional copy. | Nothing you type leaves your browser. | Results vary on each run because selection is random. - Sources: /methodology/ ## Tool: Daily Hydration Calculator - URL: https://boringtoolskit.com/daily-hydration-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate your daily water intake from body weight, activity minutes, and climate temperature. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Baseline from body weight, adjusted for activity and climate: base ≈ weight × 0.5 oz, plus activity water, times a climate factor (0.9 cool – 1.45 very hot). - Assumptions: The weight-based formula is a reasonable baseline. | Activity and climate adjustments are approximate. | No medical conditions change the requirement. - Sources: https://en.wikipedia.org/wiki/Drinking_water | https://boringtoolskit.com/methodology/ ## Tool: Data Storage Converter - URL: https://boringtoolskit.com/data-storage-converter/ - Category: Converters - Evidence: catalogue - Description: Data storage converter: bytes, KB, MB, GB, TB (binary 1024 base). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Data Transfer Rate Calculator - URL: https://boringtoolskit.com/data-transfer-rate-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate how long a file takes to transfer at a given speed, or the effective rate given size and time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Transfer time = file size (GB) × 8,000 ÷ speed (Mbps). Result in seconds, minutes, or hours. It converts between bits and bytes (8 bits per byte). - Assumptions: The connection runs at the entered speed. | 8 bits = 1 byte. | No overhead or throttling is modeled. - Sources: https://en.wikipedia.org/wiki/Data-rate_units | https://boringtoolskit.com/methodology/ ## Tool: Date Calculator Workspace - URL: https://boringtoolskit.com/date-calculator-workspace/ - Category: Time & Work - Evidence: authored-methodology - Description: Compare dates or add and subtract calendar units with leap-day and month-end handling. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Adds or subtracts days, weeks, months, and years to a date, and finds the difference between two dates. The tool reports the result weekday and handles month-length and leap-year boundaries. - Assumptions: The Gregorian calendar applies. | Dates are interpreted at midnight. | Month-end clamping follows calendar rules. - Sources: https://en.wikipedia.org/wiki/Gregorian_calendar | https://boringtoolskit.com/methodology/ ## Tool: Date Difference Calculator - URL: https://boringtoolskit.com/date-difference-calculator/ - Category: Time & Work - Evidence: authored-methodology - Description: Calculate elapsed years, months, weeks, and days between two dates. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Days = |end date − start date| in whole days, from local midnight. The tool also reports the difference in weeks, months, and years. - Assumptions: Both dates are interpreted at local midnight. | The calendar (Gregorian) is the reference. | The difference is absolute (order doesn't matter). - Sources: https://en.wikipedia.org/wiki/Gregorian_calendar | https://boringtoolskit.com/methodology/ ## Tool: Day of the Week Calculator - URL: https://boringtoolskit.com/day-of-the-week-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Day of the week calculator: what weekday was any date, plus week number and day of year. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Days Between Dates Calculator - URL: https://boringtoolskit.com/days-between-dates-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Find the number of days, weeks, and weekdays between two dates. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Days = (end date − start date) ÷ 86,400,000 ms per day, computed on calendar dates at midnight. Weeks = days ÷ 7. Weekday count iterates the calendar days between the dates, excluding weekends. - Assumptions: Both dates are interpreted at local midnight. | The end date is later than the start date. | Weekday count excludes Saturdays and Sundays only. - Sources: https://www.calculatorsoup.com/calculators/time/date-difference-calculator.php | https://boringtoolskit.com/methodology/ ## Tool: dB to Volume Ratio Calculator - URL: https://boringtoolskit.com/db-to-volume-calculator/ - Category: Music & Audio - Evidence: authored-methodology - Description: Convert decibels to power or amplitude ratios for audio gain changes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Power ratio = 10^(dB ÷ 10). Amplitude ratio = 10^(dB ÷ 20). Percent change = (ratio − 1) × 100. - Assumptions: A change of 10 dB is a 10× power ratio and a ~3.16× amplitude ratio. | The dB value is a relative change, not an absolute level. | Power and amplitude use different factors (10 vs 20). - Sources: https://boringtoolskit.com/methodology/ ## Tool: DCA Investment Calculator - URL: https://boringtoolskit.com/dca-investment-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate recurring-investment growth, contributions, and gains using monthly compounding. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Simulates monthly contributions compounding: each month, new value = (current value + contribution) × (1 + monthly return). Monthly return = annual return ÷ 12. - Assumptions: Contributions are made monthly at the entered amount. | Returns compound monthly at the constant annual rate. | No withdrawals are made. - Sources: https://en.wikipedia.org/wiki/Dollar_cost_averaging | https://boringtoolskit.com/methodology/ ## Tool: Debt Avalanche Calculator - URL: https://boringtoolskit.com/debt-avalanche-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Debt avalanche calculator: pay off highest-interest debt first to minimize interest. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Debt Consolidation Calculator - URL: https://boringtoolskit.com/debt-consolidation-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Debt consolidation calculator: current debts vs one consolidation loan. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Debt Free Date Calculator - URL: https://boringtoolskit.com/debt-free-date-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Debt free date calculator: payoff timeline at a monthly payment. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Debt Payoff Calculator - URL: https://boringtoolskit.com/debt-payoff/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate one debt's payoff timeline and compare a fixed payment with an extra-payment scenario. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Debt payoff simulates applying a monthly payment (plus any extra) to a balance, accruing interest at the monthly rate. It finds the number of months to clear the balance and the total interest paid — showing how an extra payment shortens the term. - Assumptions: A fixed APR applied monthly (APR ÷ 12) on the outstanding balance. | Payments are consistent and you make no new charges. | The model uses monthly compounding on the remaining balance. - Sources: https://www.investopedia.com/terms/d/debt-payoff.asp | https://boringtoolskit.com/methodology/ ## Tool: DSCR Calculator - URL: https://boringtoolskit.com/debt-service-coverage-ratio-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate the debt service coverage ratio (DSCR) for a rental property. Enter net operating income and annual debt service. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Debt-service coverage ratio (DSCR) = net operating income ÷ annual debt service. A DSCR above 1.0 means the property generates enough income to cover its loan payment; most lenders prefer 1.25 or higher. - Assumptions: NOI excludes debt service, taxes, and capex. | Annual debt service is the full monthly P&I payment × 12. | Lenders typically want ≥ 1.25; some accept 1.1 for strong borrowers. - Sources: https://www.investopedia.com/terms/d/dscr.asp | https://boringtoolskit.com/methodology/ ## Tool: Debt Snowball Calculator - URL: https://boringtoolskit.com/debt-snowball-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Debt snowball calculator: pay off debts smallest-first with extra payments. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Debt-to-Income Ratio Calculator - URL: https://boringtoolskit.com/debt-to-income-ratio-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate your front-end and back-end DTI ratio from monthly income, housing, and debt payments. Free, private, no signup. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Debt-to-income (DTI) ratio = total monthly debt payments ÷ gross monthly income × 100. The calculator sums housing, car, student, credit-card, and other debts and divides by gross monthly income. - Assumptions: DTI uses gross monthly income. | Debt payments are minimum required monthly payments. | The ratio is back-end (all debts) unless you focus on housing only. - Sources: https://www.investopedia.com/terms/d/debt-to-income-ratio.asp | https://boringtoolskit.com/methodology/ ## Tool: Decimal to Fraction Calculator - URL: https://boringtoolskit.com/decimal-to-fraction-calculator/ - Category: School & Education - Evidence: catalogue - Description: Decimal to fraction calculator: convert a decimal to a simplified fraction. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Deck Board Calculator - URL: https://boringtoolskit.com/deck-board-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Deck board calculator: decking boards for a deck area. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Deck Stain Calculator - URL: https://boringtoolskit.com/deck-stain-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Deck stain calculator: gallons of stain from deck area and coats, with coverage assumptions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Decking Calculator - URL: https://boringtoolskit.com/decking-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate deck boards and linear footage using deck dimensions, board width, gap, and waste. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Courses = ceil((deck width × 12) ÷ (board width + gap)). Linear feet = courses × deck length. With waste = linear feet × (1 + waste%). Boards = ceil(with waste ÷ board length). - Assumptions: The deck surface is a rectangle laid straight. | Board width and gap are in inches. | Boards are purchased in the entered length. - Sources: https://en.wikipedia.org/wiki/Deck_(building) | https://boringtoolskit.com/methodology/ ## Tool: Degree Progress Calculator - URL: https://boringtoolskit.com/degree-progress-calculator/ - Category: School & Education - Evidence: catalogue - Description: Degree progress calculator: completion percentage, remaining credits, and terms to finish. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Dehumidifier Sizing Calculator - URL: https://boringtoolskit.com/dehumidifier-sizing-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Dehumidifier sizing calculator: pints per day by room size and dampness. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Delay Time Calculator - URL: https://boringtoolskit.com/delay-time-calculator/ - Category: Music & Audio - Evidence: catalogue - Description: Delay time calculator: note-based delay milliseconds from BPM for quarter, eighth, dotted, and triplet notes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Density Calculator - URL: https://boringtoolskit.com/density-calculator/ - Category: Physics - Evidence: authored-methodology - Description: Calculate density from mass and volume (ρ = m/V) in kg/m³ and g/cm³. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Density (ρ) = mass ÷ volume. Units: kg/m³. Conversion: g/cm³ = kg/m³ ÷ 1000. - Assumptions: Mass is in kilograms and volume in cubic meters. | The material is assumed homogeneous. | Positive values are required for both inputs. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Depop Fee Calculator - URL: https://boringtoolskit.com/depop-fee-calculator/ - Category: Seller & Business - Evidence: catalogue - Description: Depop fee calculator: the 10% selling fee plus payment processing and your net. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Depreciation Calculator - URL: https://boringtoolskit.com/depreciation-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate straight-line or declining-balance depreciation over an asset's life. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Straight line: annual depreciation = (cost − salvage) ÷ useful life. Declining balance (double): first-year depreciation = cost × (2 ÷ life); the tool reports the first-year amount and ending book value for the selected method. - Assumptions: Salvage value is the estimated resale value at the end of life. | Straight line spreads the depreciable base evenly. | Declining balance reports the first-year amount using a double-declining rate. - Sources: https://www.investopedia.com/terms/d/depreciation.asp | https://boringtoolskit.com/methodology/ ## Tool: Depth of Field Calculator - URL: https://boringtoolskit.com/depth-of-field-calculator/ - Category: Photo & Video - Evidence: catalogue - Description: Depth of field calculator: estimate near and far focus limits from focal length, aperture, subject distance, and circle of confusion. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Dice Roller - URL: https://boringtoolskit.com/dice-roller/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Roll 1–10 selectable D4, D6, D8, D10, D12, or D20 dice using unbiased local browser randomness. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Simulates rolls of standard dice (D4, D6, D8, D10, D12, D20) with a uniform random generator, summing multiple dice. - Assumptions: Dice are fair (uniform distribution). | Each roll is independent. | Standard die types are sufficient. - Sources: https://en.wikipedia.org/wiki/Dice | https://boringtoolskit.com/methodology/ ## Tool: Diesel vs Gas Calculator - URL: https://boringtoolskit.com/diesel-vs-gas-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Diesel vs gas calculator: per-mile fuel cost comparison. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Dilution Calculator (C1V1=C2V2) - URL: https://boringtoolskit.com/dilution-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Solve dilution problems using C1V1 = C2V2 to find stock or final volumes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: C₁V₁ = C₂V₂. Leave one of C₁, V₁, C₂, V₂ blank and the tool solves for it. - Assumptions: Fill exactly three of the four variables; the fourth is solved. | Volume units must be consistent across V₁ and V₂. | Dilution assumes the solute is the limiting component and volumes are additive. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Percent Off Calculator - URL: https://boringtoolskit.com/discount-percent-off-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Calculate stacked percent-off discounts, apply a coupon, then add tax to see your final sale price. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Applies discounts sequentially: price × (1 − d1) × (1 − d2), subtracts a coupon, then adds tax: final = (discounted − coupon) × (1 + tax%). The tool also shows the total savings. - Assumptions: Percent discounts apply before the coupon. | Tax applies to the discounted total. | Discounts are multiplicative, not additive. - Sources: https://en.wikipedia.org/wiki/Discounts_and_allowances | https://boringtoolskit.com/methodology/ ## Tool: Distance Between Coordinates Calculator - URL: https://boringtoolskit.com/distance-between-coordinates-calculator/ - Category: Geography - Evidence: catalogue - Description: Distance between coordinates calculator: great-circle distance (haversine) between two latitude/longitude points. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Distance Between ZIP Codes Calculator - URL: https://boringtoolskit.com/distance-between-zips-calculator/ - Category: Converters - Evidence: catalogue - Description: Distance between ZIP codes calculator: straight-line miles. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Distance Modulus Calculator - URL: https://boringtoolskit.com/distance-modulus-calculator/ - Category: Astronomy - Evidence: catalogue - Description: Distance modulus calculator: distance from apparent and absolute magnitude. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Dividend Reinvestment Calculator - URL: https://boringtoolskit.com/dividend-reinvestment-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate portfolio growth when dividends are reinvested with editable yield and price growth. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Simulates monthly: dividend = current value × yield ÷ 12, reinvested into more shares, while the share price grows at the growth rate. Final value = accumulated shares × price; total dividends = sum of payments. - Assumptions: Dividends are reinvested monthly at the stated yield. | Growth is constant and compounded. | Taxes on dividends are not modeled. - Sources: https://en.wikipedia.org/wiki/Dividend_reinvestment_plan | https://boringtoolskit.com/methodology/ ## Tool: Dividend Yield Calculator - URL: https://boringtoolskit.com/dividend-yield-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Dividend yield calculator: yield from annual dividends per share and price, plus income for your shares. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: DNA GC Content Calculator - URL: https://boringtoolskit.com/dna-gc-content-calculator/ - Category: Biology - Evidence: catalogue - Description: DNA GC content calculator: GC and AT percentage from nucleotide counts. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Dog Food Calculator - URL: https://boringtoolskit.com/dog-food-calculator/ - Category: Pets - Evidence: catalogue - Description: Dog food calculator: daily calories and cups from dog weight. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Dot Product Calculator - URL: https://boringtoolskit.com/dot-product-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Dot product calculator: scalar product of two 3D vectors. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Doubling Time Calculator - URL: https://boringtoolskit.com/doubling-time-calculator/ - Category: Biology - Evidence: catalogue - Description: Doubling time calculator: population or cell culture generation time from start and end counts. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Down Payment Calculator - URL: https://boringtoolskit.com/down-payment-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate your down payment, loan amount, closing costs, and cash needed to close in percent or dollar-amount mode. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Down payment = home price × down payment % (or the entered amount). Cash needed = down payment + closing costs (closing % × price), compared against available cash. - Assumptions: Closing costs are a flat percent of the price. | The buyer pays down payment plus closing costs from cash. | PMI and escrow are evaluated separately. - Sources: https://en.wikipedia.org/wiki/Down_payment | https://boringtoolskit.com/methodology/ ## Tool: DPI Calculator - URL: https://boringtoolskit.com/dpi-calculator/ - Category: Converters - Evidence: catalogue - Description: DPI calculator: pixels per inch from pixel dimensions and print size. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: DPS Calculator - URL: https://boringtoolskit.com/dps-calculator/ - Category: Gaming - Evidence: catalogue - Description: DPS calculator: damage per second from average hit damage and attack rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Dress Size Converter - URL: https://boringtoolskit.com/dress-size-converter/ - Category: Converters - Evidence: catalogue - Description: Dress size converter: US to EU and UK dress sizes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Drywall Calculator - URL: https://boringtoolskit.com/drywall-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate drywall sheets, joint compound, screws, waste, and optional sheet cost for a room. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Net area = wall perimeter × height + optional ceiling − openings; sheets = ceiling(net area × (1 + waste) ÷ sheet area). - Assumptions: Room is rectangular and uses one drywall layer. | Opening deductions and waste are entered by the user. | Fasteners and joint compound are rough planning estimates; manufacturer instructions control. - Sources: https://www.usg.com/content/usgcom/en/resource-center.html | https://www.osha.gov/construction ## Tool: DSCR Calculator - URL: https://boringtoolskit.com/dscr-calculator/ - Category: Real Estate - Evidence: catalogue - Description: Debt service coverage ratio calculator: net operating income against annual debt payments for rental properties. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Due Date Calculator - URL: https://boringtoolskit.com/due-date-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate your pregnancy due date from your last period or conception date. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Due date = last menstrual period (LMP) + 280 days (40 weeks). Conception date ≈ due date − 266 days. From conception date mode: due date = conception + 266 days. - Assumptions: A regular 28-day cycle with ovulation at day 14. | The pregnancy is a single baby (multiples often deliver earlier). | The entered LMP or conception date is accurate. - Sources: https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2017/05/methods-for-estimating-the-due-date | https://boringtoolskit.com/methodology/ ## Tool: eBay Fee Calculator - URL: https://boringtoolskit.com/ebay-fee-calculator/ - Category: Seller & Business - Evidence: catalogue - Description: eBay fee calculator: final value fees and net proceeds for a sale including shipping. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: eBay Fee and Profit Calculator - URL: https://boringtoolskit.com/ebay-fee-profit-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Free eBay fee calculator: estimate final value, per-order, and promoted-listing fees plus net profit and margin , with editable 2026 fee rates. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Revenue = sale price + shipping charged. Fees = revenue × (final value fee % + promoted rate %) + fixed fee. Net = revenue − fees − item cost − shipping cost. - Assumptions: The final value fee applies to item + shipping. | Promoted rate applies when the seller opts in. | Insertion-fee allowances and subscriptions are separate. - Sources: https://en.wikipedia.org/wiki/Ebay | https://boringtoolskit.com/methodology/ ## Tool: EBITDA Calculator - URL: https://boringtoolskit.com/ebitda-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: EBITDA calculator: earnings before interest, taxes, depreciation, amortization. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Effective Field Goal Percentage Calculator - URL: https://boringtoolskit.com/effective-field-goal-percentage-calculator/ - Category: Sports - Evidence: catalogue - Description: Effective field goal percentage calculator: eFG% that counts threes as 1.5 makes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Egg Boil Time Calculator - URL: https://boringtoolskit.com/egg-boil-time-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Egg boil time calculator: doneness from boiling minutes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Electric Bill Estimator - URL: https://boringtoolskit.com/electric-bill-estimator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Electric bill estimator: monthly bill from kWh usage, rate, and fixed fees. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Electricity Cost Calculator - URL: https://boringtoolskit.com/electricity-cost-calculator/ - Category: Energy & Electrical - Evidence: authored-methodology - Description: Estimate appliance energy use and daily, monthly, and annual electricity cost. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: For each appliance: monthly kWh = watts ÷ 1,000 × hours per active day × active days per month; annual kWh = monthly kWh × 12; cost = kWh × electricity rate. Comparison mode subtracts Appliance B from Appliance A and simple payback = additional purchase cost ÷ annual savings when annual savings are positive. - Assumptions: Power draw, active hours, and active days are treated as constant user assumptions. | Annual use follows the entered monthly schedule by multiplying monthly kWh by 12. | Taxes, demand charges, time-of-use rates, standby power, maintenance, rebates, and lifespan are excluded unless you account for them separately. | Worked example: A 1,500-watt appliance used 4 hours per day for 30 active days at $0.20 per kWh uses 180 kWh and costs $36 for that month; annualizing the same schedule gives $432. | Nameplate watts may differ from average draw as appliances cycle, enter standby, or change load. - Sources: https://www.eia.gov/energyexplained/use-of-energy/electricity-use-in-homes.php | https://www.eia.gov/electricity/data/browser/ ## Tool: Electron Configuration Calculator - URL: https://boringtoolskit.com/electron-configuration-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Find the electron configuration for any element by atomic number. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Fills electrons into orbitals following the Aufbau order (1s, 2s, 2p, 3s, 3p, 4s, 3d, ...) for the given atomic number (1–118). - Assumptions: The atomic number must be between 1 and 118. | The configuration follows the standard Aufbau sequence (with common exceptions for some transition metals not modeled). | The result is the ground-state electron configuration. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Ellipse Calculator - URL: https://boringtoolskit.com/ellipse-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Ellipse calculator: area and approximate circumference. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Email Preview Tester - URL: https://boringtoolskit.com/email-preview-tester/ - Category: Text & Developer Tools - Evidence: authored-methodology - Description: Preview sender, subject line, and preheader truncation across representative inbox layouts. Runs privately in your browser. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Checks subject lines and sender names against client display budgets (Gmail, Apple Mail, Outlook, Yahoo) in compact, wide, and desktop layouts, flagging likely truncation. - Assumptions: Client display budgets reflect current layouts. | Character counts are approximate. | The subject is the first line of the email. - Sources: https://en.wikipedia.org/wiki/Email | https://boringtoolskit.com/methodology/ ## Tool: Emergency Fund Calculator - URL: https://boringtoolskit.com/emergency-fund-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate an emergency-fund target, current gap, and time needed to reach it. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Target = monthly expenses × months of coverage. Gap = target − current savings. Time to reach = gap ÷ monthly contribution. - Assumptions: Expenses are essential, recurring costs. | The fund is held separately and untouched. | The monthly contribution is sustained. - Sources: https://en.wikipedia.org/wiki/Emergency_fund | https://boringtoolskit.com/methodology/ ## Tool: EMI Calculator - URL: https://boringtoolskit.com/emi-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the equated monthly installment (EMI) for a fixed-rate loan, plus total interest and an amortization schedule. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), where P = principal, r = monthly interest rate (annual ÷ 12), and n = number of monthly payments. Total payment = EMI × n; total interest = total payment − principal. - Assumptions: The interest rate is fixed for the full term. | Payments are made monthly at the end of each period. | Fees, insurance, and taxes are not included. - Sources: https://www.calculatorsoup.com/calculators/financial/loan-calculator.php | https://boringtoolskit.com/methodology/ ## Tool: Empirical Formula Calculator - URL: https://boringtoolskit.com/empirical-formula-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Find the empirical formula from percent composition or mass data. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Convert each element's mass or percent to moles (mass ÷ atomic mass), divide by the smallest value, and round to the nearest whole-number ratio to get the empirical formula. - Assumptions: Each element's mass or percent is entered as element:value or element,value. | Atomic masses use the standard values embedded in the tool. | The result is the simplest whole-number ratio, not necessarily the molecular formula. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Employee Turnover Calculator - URL: https://boringtoolskit.com/employee-turnover-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Employee turnover rate calculator. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Endpoint Calculator - URL: https://boringtoolskit.com/endpoint-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Endpoint calculator: missing endpoint from midpoint and one endpoint. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Energy Converter - URL: https://boringtoolskit.com/energy-converter/ - Category: Converters - Evidence: catalogue - Description: Energy converter: joules, kilowatt-hours, calories, BTUs. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Engagement Rate Calculator - URL: https://boringtoolskit.com/engagement-rate-calculator/ - Category: Social Media - Evidence: authored-methodology - Description: Calculate social media engagement rate from followers, likes, comments, and shares. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Engagement rate = (likes + comments + shares) ÷ followers × 100. Interactions = likes + comments + shares. - Assumptions: Engagement is limited to likes, comments, and shares entered. | The follower count is the audience at the time of the post. | Rates are a planning metric; platform algorithms and reach are not modeled. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Engine Horsepower Calculator - URL: https://boringtoolskit.com/engine-horsepower-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Engine horsepower calculator: estimate HP from weight and quarter-mile ET (trap method). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: EOQ Calculator - URL: https://boringtoolskit.com/eoq-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: EOQ calculator: economic order quantity for inventory. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Equalizer Q Calculator - URL: https://boringtoolskit.com/equalizer-q-calculator/ - Category: Music & Audio - Evidence: catalogue - Description: Equalizer Q calculator: filter Q from center frequency and bandwidth, in Hz or octaves. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Equilibrium Constant Calculator - URL: https://boringtoolskit.com/equilibrium-constants-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Calculate the equilibrium constant K from reactant and product concentrations. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: For aA + bB ⇌ cC + dD, K = [C]^c × [D]^d ÷ [A]^a × [B]^b. - Assumptions: Coefficients and concentrations for the products and at least one reactant are required. | Concentrations use the entered values; the tool does not solve for equilibrium positions. | Solids and pure liquids are not entered in the concentration terms. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Estate Tax Calculator - URL: https://boringtoolskit.com/estate-tax-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Estate tax calculator: federal estate tax above the lifetime exemption. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Etsy Fee & Profit Calculator - URL: https://boringtoolskit.com/etsy-fee-profit/ - Category: Seller & Business - Evidence: authored-methodology - Description: Free Etsy fee calculator: estimate listing, transaction, and payment processing fees plus profit. Enter price and costs, see net earnings and margins. Privat. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Gross = sale price × quantity + shipping charged. Fees = listing fee ($0.20/item) + transaction fee (6.5% of gross) + payment processing (3% + $0.25) + offsite ads % + other. Net = gross − fees − costs. - Assumptions: Current Etsy fee rates apply (listing $0.20, transaction 6.5%). | Payment processing is 3% + $0.25 per transaction. | The offsite ads rate reflects the seller's tier. - Sources: https://en.wikipedia.org/wiki/Etsy | https://boringtoolskit.com/methodology/ ## Tool: EV Charge Time Calculator - URL: https://boringtoolskit.com/ev-charge-time-calculator/ - Category: Vehicles - Evidence: catalogue - Description: EV charge time calculator: hours to charge an EV battery. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: EV Charging Cost Calculator - URL: https://boringtoolskit.com/ev-charging-cost-calculator/ - Category: Energy & Electrical - Evidence: authored-methodology - Description: Estimate energy drawn, per-charge cost, monthly charging cost, and cost per mile for an EV. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Battery energy added = capacity × charge-window percentage; grid energy = battery energy ÷ (1 − loss); cost = grid energy × rate. - Assumptions: Usable battery capacity equals the entered capacity. | Charging loss and electricity rate remain constant. | Taxes, demand charges, time-of-use pricing, idle fees, and public-network fees are excluded. - Sources: https://afdc.energy.gov/fuels/electricity_charging_home.html | https://www.fueleconomy.gov/feg/evtech.shtml ## Tool: EV Range Calculator - URL: https://boringtoolskit.com/ev-range-calculator/ - Category: Vehicles - Evidence: catalogue - Description: EV range calculator: electric car range from battery and consumption. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: EV vs Gas Savings Calculator - URL: https://boringtoolskit.com/ev-vs-gas-savings-calculator/ - Category: Vehicles - Evidence: catalogue - Description: EV vs gas savings calculator: annual fuel cost of an electric car versus a gas car. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Expected Value Calculator - URL: https://boringtoolskit.com/expected-value-calculator/ - Category: Statistics - Evidence: catalogue - Description: Expected value calculator: EV from two outcomes with probabilities and values. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Expense Split Calculator - URL: https://boringtoolskit.com/expense-split-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Expense split calculator: split a bill evenly. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Exponent Calculator - URL: https://boringtoolskit.com/exponent-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate a base raised to an exponent, including negative and fractional exponents. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Result = base^exponent (Math.pow(base, exponent)). Negative exponents give the reciprocal: 2⁻² = 1 ÷ 2² = 0.25. Fractional exponents give roots: 8^(1/3) = 2. - Assumptions: Standard real-number exponentiation applies. | Results are finite and real (complex results are flagged invalid). | Zero to a negative exponent is undefined. - Sources: https://www.mathsisfun.com/exponent.html | https://boringtoolskit.com/methodology/ ## Tool: Exponential Growth Calculator - URL: https://boringtoolskit.com/exponential-growth-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Exponential growth calculator: value after continuous growth. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Exposure Value Calculator - URL: https://boringtoolskit.com/exposure-value-calculator/ - Category: Photo & Video - Evidence: catalogue - Description: Exposure value calculator: EV from aperture, shutter speed, and ISO. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Fabric Yardage Calculator - URL: https://boringtoolskit.com/fabric-yardage-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Fabric yardage calculator: yards of fabric for a project. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Facebook Ads Cost Calculator - URL: https://boringtoolskit.com/facebook-ads-cost-calculator/ - Category: Social Media - Evidence: authored-methodology - Description: Calculate Facebook ads CPM, CPC, CTR, and ROAS from campaign data. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Estimated spend = impressions × (CTR ÷ 100) × CPC. Clicks = impressions × (CTR ÷ 100). - Assumptions: CTR and CPC are the user's estimates from prior campaigns or benchmarks. | Impressions, clicks, and cost are not guaranteed to scale linearly with spend. | Bidding, audience, and creative quality materially change real cost. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Factorial Calculator - URL: https://boringtoolskit.com/factorial-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Factorial calculator: n! for any integer up to 170. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: n! = n × (n−1) × … × 1, with 0! = 1. - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Fasting Window Calculator - URL: https://boringtoolskit.com/fasting-window-calculator/ - Category: Health - Evidence: catalogue - Description: Fasting window calculator: eating window from fast start and length. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Federal Income Tax Calculator - URL: https://boringtoolskit.com/federal-income-tax-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Federal income tax calculator: 2026 federal brackets with standard deduction. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Fence Material Calculator - URL: https://boringtoolskit.com/fence-material-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate fence sections, posts, rails, and pickets from run length and spacing. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Sections = ceil(fence length ÷ section length). Posts = sections + 1. Rails = sections × rails per section. Pickets = ceil(fence length × 12 ÷ picket width). - Assumptions: A straight fence run with no gates or corners. | Pickets are installed edge-to-edge at the entered width. | Posts are placed at each section boundary. - Sources: https://en.wikipedia.org/wiki/Picket_fence | https://boringtoolskit.com/methodology/ ## Tool: Fence Post Calculator - URL: https://boringtoolskit.com/fence-post-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Fence post calculator: posts and rails for a fence run. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Fetal Weight Calculator - URL: https://boringtoolskit.com/fetal-weight-calculator/ - Category: Health - Evidence: catalogue - Description: Fetal weight calculator: estimated baby weight from ultrasound (Hadlock). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: FHA Loan Calculator - URL: https://boringtoolskit.com/fha-loan-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: FHA loan calculator: payment with mortgage insurance premium (MIP). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Fibonacci Calculator - URL: https://boringtoolskit.com/fibonacci-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Fibonacci calculator: nth Fibonacci number. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: F(0) = 0, F(1) = 1, and F(n) = F(n−1) + F(n−2) for n ≥ 2. - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Field Goal Probability Calculator - URL: https://boringtoolskit.com/field-goal-probability-calculator/ - Category: Sports - Evidence: catalogue - Description: Field goal probability calculator: estimated make probability from kick distance. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Final Exam Grade Calculator - URL: https://boringtoolskit.com/final-exam-calculator/ - Category: School & Education - Evidence: authored-methodology - Description: See the exact score you need on your final exam to reach your desired course grade. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Required final score = (desired course grade − current grade × (1 − final weight/100)) ÷ (final weight/100). This is the exact formula the live calculator uses: need = (desired − current×(1−w/100)) ÷ (w/100). - Assumptions: Enter current grade, desired course grade, and final weight as percentages on the same 0–100 scale. | The final must be the only remaining scored item; if other graded work remains, the true required score differs. | If the required score is above 100, no realistic final can reach the goal (the calculator reports the resulting course floor). - Sources: /methodology/ | https://en.wikipedia.org/wiki/Grading_in_education ## Tool: Five Number Summary Calculator - URL: https://boringtoolskit.com/five-number-summary-calculator/ - Category: Statistics - Evidence: catalogue - Description: Five number summary calculator: min, quartiles, median, max, IQR and outliers. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Fix and Flip Profit Calculator - URL: https://boringtoolskit.com/fix-and-flip-profit-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Project full profit on a fix-and-flip. Enter purchase, rehab, holding and selling costs, and after-repair value. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Fix-and-flip profit = sale price (or after-repair value) − purchase price − rehabilitation cost − holding costs − closing costs. The result is the expected profit after all expenses. - Assumptions: Profit is sale price minus all entered costs. | The tool supports using an after-repair value or an entered sale price. | Holding and closing costs are user estimates. - Sources: https://www.investopedia.com/terms/f/fix-and-flip.asp | https://boringtoolskit.com/methodology/ ## Tool: Flash Guide Number Calculator - URL: https://boringtoolskit.com/flash-guide-number-calculator/ - Category: Photo & Video - Evidence: catalogue - Description: Flash guide number calculator: solve guide number, aperture, or distance for flash photography. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Flight Carbon Footprint Calculator - URL: https://boringtoolskit.com/flight-carbon-footprint-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Flight carbon footprint calculator: estimated CO2 per passenger for a flight, by distance and cabin class. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Flight Delay Compensation Calculator - URL: https://boringtoolskit.com/flight-delay-compensation-calculator/ - Category: Travel - Evidence: catalogue - Description: Flight delay compensation calculator: EU261 compensation for delayed flights by distance. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Flooring Calculator - URL: https://boringtoolskit.com/flooring-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate flooring area, waste allowance, and boxes required for a room. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Room area = length × width. Area with waste = room area × (1 + waste%). Boxes required = ceil(area with waste ÷ box coverage). Purchased coverage = boxes × box coverage. - Assumptions: The room is rectangular. | Waste percentage is entered by the user. | Boxes are rounded up to whole numbers. - Sources: https://www.calculatorsoup.com/calculators/construction/square-footage-calculator.php | https://boringtoolskit.com/methodology/ ## Tool: Focal Length Calculator - URL: https://boringtoolskit.com/focal-length-calculator/ - Category: Photo & Video - Evidence: catalogue - Description: Focal length calculator: estimate focal length from sensor width, subject distance, and field-of-view width. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Folder to Prompt - URL: https://boringtoolskit.com/folder-to-prompt/ - Category: Text & Developer Tools - Evidence: authored-methodology - Description: Turn a local project folder into a structured AI prompt without uploading its files. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Bundles selected folder files into a single prompt text with file paths, skipping binary files and security-sensitive paths (.git, node_modules, .env, credentials, keys). - Assumptions: The user reviews output before sharing it. | Security-blocked paths cover common secret files. | Binary files are excluded from the bundle. - Sources: https://en.wikipedia.org/wiki/Prompt_engineering | https://boringtoolskit.com/methodology/ ## Tool: Follower Growth Calculator - URL: https://boringtoolskit.com/follower-growth-calculator/ - Category: Social Media - Evidence: authored-methodology - Description: Project follower growth from starting audience, growth rate, and timeline. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Projected followers = current × (1 + monthly growth rate ÷ 100)^months. Net gain = projected − current. - Assumptions: The growth rate is applied monthly and compounds. | Growth is assumed steady; real accounts fluctuate and may plateau. | The projection is forward-looking, not a guarantee. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Food Cost Calculator - URL: https://boringtoolskit.com/food-cost-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Food cost calculator: ingredient cost per serving and food-cost percentage for menu pricing. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Food Safety Temperature Calculator - URL: https://boringtoolskit.com/food-safety-temperature-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Food safety temperature calculator: safe internal temperatures. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Food Storage Time Calculator - URL: https://boringtoolskit.com/food-storage-time-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Food storage time guide: safe refrigerator and freezer storage times for common foods. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Force Calculator - URL: https://boringtoolskit.com/force-calculator/ - Category: Physics - Evidence: authored-methodology - Description: Calculate force, mass, or acceleration using Newton's second law (F = ma). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Force (F) = mass × acceleration. Units: newtons (N) = kg · m/s². - Assumptions: Mass is in kilograms and acceleration in m/s². | The calculation assumes a constant, net force with no friction. | Positive values are required for both inputs. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: FPS Sensitivity Converter - URL: https://boringtoolskit.com/fps-sensitivity-converter/ - Category: Gaming - Evidence: catalogue - Description: FPS sensitivity converter: convert mouse sensitivity between games and calculate eDPI and cm/360. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Fraction Operations Calculator - URL: https://boringtoolskit.com/fraction-operations-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Fraction operations calculator: add, subtract, multiply, divide fractions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: a/b + c/d = (ad + bc)/(bd); multiply: (a/b) × (c/d) = ac/bd. - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Simplify Fractions Calculator - URL: https://boringtoolskit.com/fraction-simplify-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Reduce any fraction to lowest terms with the GCD shown, plus decimal and mixed-number forms. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Simplifies a fraction by dividing numerator and denominator by their greatest common divisor (GCD). - Assumptions: The fraction is proper or improper but valid. | The denominator is not zero. | Simplest form uses positive integers. - Sources: https://en.wikipedia.org/wiki/Fraction | https://boringtoolskit.com/methodology/ ## Tool: Fraction to Decimal Calculator - URL: https://boringtoolskit.com/fraction-to-decimal-calculator/ - Category: School & Education - Evidence: catalogue - Description: Fraction to decimal calculator: numerator over denominator as a decimal and percent. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Fractions Calculator - URL: https://boringtoolskit.com/fractions-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Add, subtract, multiply, or divide two fractions and get the simplified result. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Add: (n1×d2 + n2×d1) ÷ (d1×d2). Subtract: (n1×d2 − n2×d1) ÷ (d1×d2). Multiply: (n1×n2) ÷ (d1×d2). Divide: (n1×d2) ÷ (d1×n2). The result is simplified by dividing numerator and denominator by their greatest common divisor. - Assumptions: Neither denominator is zero. | Inputs are integers (whole-number numerators and denominators). | Results are reduced to lowest terms. - Sources: https://www.mathsisfun.com/fractions.html | https://boringtoolskit.com/methodology/ ## Tool: Frame Rate Duration Calculator - URL: https://boringtoolskit.com/frame-rate-duration-calculator/ - Category: Photo & Video - Evidence: catalogue - Description: Frame rate duration calculator: convert frames to seconds, minutes, or timecode at any frames-per-second rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Frame Size Calculator - URL: https://boringtoolskit.com/frame-size-calculator/ - Category: Health - Evidence: catalogue - Description: Frame size calculator: small, medium, or large body frame from wrist. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Freelance Hourly Rate Calculator - URL: https://boringtoolskit.com/freelance-hourly-rate-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Estimate a sustainable freelance hourly rate from income goals, expenses, taxes, and billable hours. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Required gross = (target take-home ÷ (1 − tax rate)) + business expenses. Hourly rate = required gross ÷ (weeks worked × hours per week × billable %). - Assumptions: Taxes are estimated at the entered rate. | Expenses are annual and fixed. | Billable % reflects real utilization. - Sources: https://en.wikipedia.org/wiki/Freelancer | https://boringtoolskit.com/methodology/ ## Tool: Frequency to Note Converter - URL: https://boringtoolskit.com/frequency-to-note-calculator/ - Category: Music & Audio - Evidence: authored-methodology - Description: Convert a sound frequency to its closest musical note with cents deviation. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: MIDI note = round(12 × log₂(freq ÷ 440)) + 69. Note name from the 12-note chromatic set. Detuning in cents = 1200 × log₂(freq ÷ 440) − 1200 × (MIDI − 69). - Assumptions: Frequency must be positive. | The reference is A4 = 440 Hz standard tuning. | The nearest note is the closest 12-tone equal-tempered pitch. - Sources: https://boringtoolskit.com/methodology/ ## Tool: FSA Calculator - URL: https://boringtoolskit.com/fsa-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: FSA calculator: tax savings and what you risk with use-it-or-lose-it. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Fuel Cost Per Mile Calculator - URL: https://boringtoolskit.com/fuel-cost-per-mile-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Fuel cost per mile calculator: cost per mile and per month from MPG and fuel price. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Fuel & Trip Cost Calculator - URL: https://boringtoolskit.com/fuel-trip-cost-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate fuel used, total trip cost, and each traveler’s share in MPG or L/100 km mode. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Fuel used = distance ÷ efficiency (MPG) or distance ÷ 100 × L/100km. Cost = fuel used × price. The tool splits the cost per traveler and per trip. - Assumptions: Efficiency is the user's real-world number. | Fuel price is per gallon or per liter as entered. | No tolls or other trip costs are included. - Sources: https://en.wikipedia.org/wiki/Fuel_economy_in_automobiles | https://boringtoolskit.com/methodology/ ## Tool: Furnace Size Calculator - URL: https://boringtoolskit.com/furnace-size-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Furnace size calculator: BTU and tonnage from square footage. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Future Value Calculator - URL: https://boringtoolskit.com/future-value-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Project the future value of a starting balance and recurring monthly contributions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Future value is calculated month by month: balance grows by annual rate ÷ 12, with deposits applied at the selected timing. - Assumptions: Rate and contributions remain constant. | Taxes, fees, and market volatility are excluded. | This is a hypothetical projection, not an investment forecast. - Sources: https://www.investor.gov/financial-tools-calculators/calculators/compound-interest-calculator | https://www.sec.gov/investor/pubs/sec-guide-to-savings-and-investing.pdf ## Tool: G Force Calculator - URL: https://boringtoolskit.com/g-force-calculator/ - Category: Physics - Evidence: catalogue - Description: G force calculator: cornering acceleration from speed and radius. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Gacha Pity Calculator - URL: https://boringtoolskit.com/gacha-pity-calculator/ - Category: Gaming - Evidence: catalogue - Description: Gacha pity calculator: honest odds of pulling the featured item within N pulls. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Garage Size Calculator - URL: https://boringtoolskit.com/garage-size-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Garage size calculator: minimum dimensions by car count. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Gas Budget Calculator - URL: https://boringtoolskit.com/gas-budget-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Gas budget calculator: monthly and yearly fuel spending. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Gas Laws Calculator - URL: https://boringtoolskit.com/gas-laws-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Apply Boyle's, Charles', and the Ideal Gas Law to gas properties. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Ideal gas law: PV = nRT with R = 0.08206 L·atm/(mol·K). Temperature is converted from °C to K (T = °C + 273.15). Leave one of P, V, n, T blank. - Assumptions: R = 0.08206 L·atm/(mol·K); pressure is in atm and volume in L. | Temperature is entered in °C and converted to Kelvin. | The ideal gas law assumes ideal behavior; real gases deviate at high pressure or low temperature. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Gas Mileage Calculator - URL: https://boringtoolskit.com/gas-mileage-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate miles per gallon or liters per 100 km from distance and fuel used. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: US: MPG = miles ÷ gallons. Metric: L/100km = (liters ÷ km) × 100. Mixed units are converted (1 mile = 1.60934 km, 1 US gallon = 3.78541 L). - Assumptions: The tank was full at both ends of the measurement. | US gallons are used for MPG. | The driving is a representative mix. - Sources: https://www.fueleconomy.gov/ | https://boringtoolskit.com/methodology/ ## Tool: GCF and LCM Calculator - URL: https://boringtoolskit.com/gcf-lcm-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Find the greatest common factor and least common multiple of two numbers. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Greatest common factor (GCF) via the Euclidean algorithm: repeatedly replace (x, y) with (y, x mod y) until y = 0; the last x is the GCF. Least common multiple: LCM = a × b ÷ GCF(a, b). - Assumptions: Both inputs are positive integers. | Standard definitions of GCF and LCM apply. | Results are exact integers. - Sources: https://www.mathsisfun.com/greatest-common-factor.html | https://boringtoolskit.com/methodology/ ## Tool: GDP Calculator - URL: https://boringtoolskit.com/gdp-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: GDP calculator: gross domestic product from consumption, investment, government, and net exports. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: General and Scientific Calculator - URL: https://boringtoolskit.com/general-scientific-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Use a fast general calculator or switch on scientific functions for trigonometry, logarithms, powers, roots, memory, and calculation history. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: A full scientific calculator with arithmetic, parentheses, powers and roots, trigonometric functions (sin/cos/tan with degree or radian mode), logarithms, constants, and memory. - Assumptions: Standard operator precedence applies. | The angle mode matches the user's intent. | Floating-point rounding is expected. - Sources: https://en.wikipedia.org/wiki/Scientific_calculator | https://boringtoolskit.com/methodology/ ## Tool: Generator Load Calculator - URL: https://boringtoolskit.com/generator-load-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Generator load calculator: wattage needed for appliances. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Generator Runtime Calculator - URL: https://boringtoolskit.com/generator-runtime-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Generator runtime calculator: hours on a tank of fuel. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Generator Size Calculator - URL: https://boringtoolskit.com/generator-size-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Generator size calculator: watts needed for running loads plus starting surge. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Geographic Area Calculator - URL: https://boringtoolskit.com/geographic-area-calculator/ - Category: Geography - Evidence: catalogue - Description: Geographic area calculator: approximate rectangle area on the globe from corner coordinates. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Geometric Distribution Calculator - URL: https://boringtoolskit.com/geometric-distribution-calculator/ - Category: Statistics - Evidence: catalogue - Description: Geometric distribution calculator: first success on trial k. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Geometric and Harmonic Mean Calculator - URL: https://boringtoolskit.com/geometric-mean-calculator/ - Category: Statistics - Evidence: catalogue - Description: Geometric and harmonic mean calculator: multiplicative-average measures for rates, ratios, and growth data. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Geometric Sequence Calculator - URL: https://boringtoolskit.com/geometric-sequence-calculator/ - Category: School & Education - Evidence: catalogue - Description: Geometric sequence calculator: nth term and sum from first term and ratio. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Gestational Age Calculator - URL: https://boringtoolskit.com/gestational-age-calculator/ - Category: Health - Evidence: catalogue - Description: Gestational age calculator: weeks pregnant and due date from last period. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: GFR Calculator - URL: https://boringtoolskit.com/gfr-calculator/ - Category: Health - Evidence: catalogue - Description: eGFR calculator (CKD-EPI 2021): estimated kidney filtration rate from creatinine, age, and sex. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Gift Tax Calculator - URL: https://boringtoolskit.com/gift-tax-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Gift tax calculator: taxable gifts above the annual exclusion. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Glove Size Calculator - URL: https://boringtoolskit.com/glove-size-calculator/ - Category: Converters - Evidence: catalogue - Description: Glove size calculator: S/M/L/XL from hand circumference. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Gold, Silver & Precious Metals Price Calculator - URL: https://boringtoolskit.com/gold-silver-precious-metals/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Live gold, silver, platinum, and palladium spot prices plus a precious-metals and rare-earth element lookup with atomic numbers, weights, and uses. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Value = weight × purity × spot price per unit. The tool converts between troy ounces and grams (1 troy oz = 31.1034768 g) and applies the metal's fineness (24k gold = 99.9% pure, 18k = 75%) to live spot prices. - Sources: https://www.gold.org/goldhub/data/gold-prices | https://boringtoolskit.com/methodology/ ## Tool: Golden Ratio Calculator - URL: https://boringtoolskit.com/golden-ratio-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Golden ratio calculator: phi times a number. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: φ ≈ 1.61803, defined by (a + b)/a = a/b = φ. - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Golf Club Distance Calculator - URL: https://boringtoolskit.com/golf-club-distance-calculator/ - Category: Sports - Evidence: catalogue - Description: Golf club distance calculator: driver distance from swing speed. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Golf Handicap Calculator - URL: https://boringtoolskit.com/golf-handicap-calculator/ - Category: Sports - Evidence: catalogue - Description: Golf handicap calculator: handicap index from score, course rating, and slope. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: GPA Calculator - URL: https://boringtoolskit.com/gpa-calculator/ - Category: School & Education - Evidence: authored-methodology - Description: Calculate your GPA on a standard 4.0 scale from course letter grades and credits. Local, private, no upload. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: GPA = Σ (grade points × course credits) ÷ Σ credits. Standard scale: A = 4.0, A− = 3.7, B+ = 3.3, B = 3.0, B− = 2.7, C+ = 2.3, C = 2.0, C− = 1.7, D+ = 1.3, D = 1.0, D− = 0.7, F = 0.0. - Assumptions: The standard 4.0 plus/minus scale is used. | All courses are unweighted. | Credits are entered as the school defines them. - Sources: https://en.wikipedia.org/wiki/Academic_grading_in_the_United_States | https://boringtoolskit.com/methodology/ ## Tool: Test Grade Calculator - URL: https://boringtoolskit.com/grade-calculator/ - Category: School & Education - Evidence: authored-methodology - Description: Convert test points into a percentage and letter grade, and see the points needed for the next grade up. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Percentage = (points earned ÷ points possible) × 100. Letter grade from the standard scale: A ≥ 90, B ≥ 80, C ≥ 70, D ≥ 60, F < 60. The tool also shows points needed for the next letter grade. - Assumptions: The standard 90/80/70/60 letter scale applies. | Points are weighted equally. | No curve or plus/minus adjustments are applied. - Sources: https://en.wikipedia.org/wiki/Grading_in_education | https://boringtoolskit.com/methodology/ ## Tool: Grade Percentage Calculator - URL: https://boringtoolskit.com/grade-percentage-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Grade percentage calculator: slope as percent and degrees. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Grams to Cups Calculator - URL: https://boringtoolskit.com/grams-to-cups-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Grams to cups calculator: weight to volume by ingredient density. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Gravel Calculator - URL: https://boringtoolskit.com/gravel-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate gravel volume, weight, waste, and optional material cost for a rectangular area. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Cubic feet = length × width × depth ÷ 12; cubic yards = cubic feet ÷ 27; tons = cubic feet × density ÷ 2,000. - Assumptions: The area is rectangular and depth is uniform. | Bulk density is editable because material type and moisture vary. | Waste does not model compaction separately unless included in the allowance. - Sources: https://www.nist.gov/pml/owm/nist-handbook-44-current-edition | https://www.usgs.gov/centers/national-minerals-information-center ## Tool: Grip Strength Calculator - URL: https://boringtoolskit.com/grip-strength-calculator/ - Category: Sports - Evidence: catalogue - Description: Grip strength calculator: handgrip rating by age and gender. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Gross Margin Calculator - URL: https://boringtoolskit.com/gross-margin-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Gross margin calculator: profit margin and markup from revenue and cost of goods sold. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Gross Rent Multiplier Calculator - URL: https://boringtoolskit.com/gross-rent-multiplier-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate the gross rent multiplier (GRM). Enter property price and annual rent for the 10-second income screen. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Gross rent multiplier (GRM) = property price ÷ annual rent. A lower GRM means a higher income yield relative to price — a faster way to compare investment properties by price-to-income. - Assumptions: Annual gross rent is monthly rent × 12. | GRM uses gross rent — no operating costs, no financing. | Comparing GRMs across different markets can be misleading. - Sources: https://www.investopedia.com/terms/g/gross-rent-multiplier.asp | https://boringtoolskit.com/methodology/ ## Tool: Gross Up Calculator - URL: https://boringtoolskit.com/gross-up-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Gross up calculator: convert a net pay or budget target to gross pay including taxes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Grout Calculator - URL: https://boringtoolskit.com/grout-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Grout calculator: pounds of grout for a tile job. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Gumroad Fee Calculator - URL: https://boringtoolskit.com/gumroad-fee-calculator/ - Category: Seller & Business - Evidence: catalogue - Description: Gumroad fee calculator: the 10% creator fee plus payment processing. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Gutter Size Calculator - URL: https://boringtoolskit.com/gutter-size-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Gutter size calculator: 5-inch or 6-inch gutter by roof area. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Gym Cost Per Visit Calculator - URL: https://boringtoolskit.com/gym-cost-per-visit-calculator/ - Category: Health - Evidence: catalogue - Description: Gym cost per visit calculator: is your membership actually worth it? - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Half Life Calculator - URL: https://boringtoolskit.com/half-life-calculator/ - Category: Physics - Evidence: catalogue - Description: Half life calculator: remaining amount after elapsed time with a known half-life. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Hardy Weinberg Calculator - URL: https://boringtoolskit.com/hardy-weinberg-calculator/ - Category: Biology - Evidence: catalogue - Description: Hardy Weinberg calculator: genotype frequencies from allele frequency under equilibrium. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Harmonic Mean Calculator - URL: https://boringtoolskit.com/harmonic-mean-calculator/ - Category: Statistics - Evidence: catalogue - Description: Harmonic mean calculator: n divided by the sum of reciprocals. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Hashtag Performance Calculator - URL: https://boringtoolskit.com/hashtag-performance-calculator/ - Category: Social Media - Evidence: authored-methodology - Description: Measure hashtag reach, impressions, and engagement rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Hashtag engagement rate = (hashtag engagement ÷ hashtag reach) × 100. Average engagement per post = engagement ÷ posts. - Assumptions: Reach and engagement are totals across the posts entered. | Engagement is measured the same way for every post. | Hashtag performance varies by topic and platform. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Hat Size Calculator - URL: https://boringtoolskit.com/hat-size-calculator/ - Category: Converters - Evidence: catalogue - Description: Hat size calculator: US hat size from head circumference. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Heart Rate Recovery Calculator - URL: https://boringtoolskit.com/heart-rate-recovery-calculator/ - Category: Health - Evidence: catalogue - Description: Heart rate recovery calculator: HR drop after exercise. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Heart Rate Zones Calculator - URL: https://boringtoolskit.com/heart-rate-zones-calculator/ - Category: Health - Evidence: catalogue - Description: Heart rate zones calculator: target training zones from age and resting heart rate, computed locally. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Heat Index Calculator - URL: https://boringtoolskit.com/heat-index-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the apparent (feels-like) temperature from air temperature and humidity. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Heat index (NWS regression, valid for T ≥ 80°F and RH ≥ 40%): HI = −42.379 + 2.04901523×T + 10.14333127×RH − 0.22475541×T×RH − 0.00683783×T² − 0.05481717×RH² + 0.00122874×T²×RH + 0.00085282×T×RH² − 0.00000199×T²×RH². Below those thresholds, HI = T. - Assumptions: The NWS heat-index regression is used. | Conditions are in the shade. | Temperature is in Fahrenheit. - Sources: https://www.weather.gov/ama/heatindex | https://boringtoolskit.com/methodology/ ## Tool: Hectare to Acre Converter - URL: https://boringtoolskit.com/hectare-acre-converter/ - Category: Converters - Evidence: catalogue - Description: Hectare to acre converter: hectares, acres, square meters. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: HELOC Calculator - URL: https://boringtoolskit.com/heloc-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate the monthly payment and total cost of a home equity line of credit. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Interest-only payment = balance × monthly rate (APR ÷ 12). Amortizing payment = balance × r ÷ (1 − (1 + r)^−n), where r is the monthly rate and n the months remaining after the draw period. - Assumptions: The rate stays constant at the entered APR. | During the draw you pay interest only, with no principal reduction. | Repayment uses a fixed-rate amortization over the remaining months. - Sources: https://www.investopedia.com/terms/h/home_equity_line_of_credit.asp | https://boringtoolskit.com/methodology/ ## Tool: Heron's Formula Calculator - URL: https://boringtoolskit.com/herons-formula-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Heron's formula calculator: triangle area from three sides. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Hex to CMYK Converter - URL: https://boringtoolskit.com/hex-to-cmyk-converter/ - Category: Colors & Design - Evidence: catalogue - Description: Hex to CMYK converter: convert a #RRGGBB hex color to CMYK values for print. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Hex to Decimal Converter - URL: https://boringtoolskit.com/hex-to-decimal/ - Category: Converters - Evidence: authored-methodology - Description: Convert hexadecimal and decimal values with an interactive positional-value explanation. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Hex to decimal: each digit's place value is a power of 16 (rightmost = 16⁰). Decimal to hex: repeatedly divide by 16 and record remainders. Colors (#RRGGBB) convert to 24-bit integers. - Assumptions: Hex input uses digits 0–9 and A–F. | The 0x prefix and # are optional. | Values stay within safe integer range. - Sources: https://en.wikipedia.org/wiki/Hexadecimal | https://boringtoolskit.com/methodology/ ## Tool: Hex to HSL Converter - URL: https://boringtoolskit.com/hex-to-hsl-converter/ - Category: Colors & Design - Evidence: catalogue - Description: Hex to HSL converter: convert a hex color to HSL values and CSS string. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: HEX to RGB Converter - URL: https://boringtoolskit.com/hex-to-rgb/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Convert any hex color code to its red, green, and blue (RGB) values instantly, in the browser. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Splits a hex color into its red, green, and blue bytes: #RRGGBB → (RR₁₆, GG₁₆, BB₁₆) in decimal (0–255). 3-digit shorthand expands each digit. - Assumptions: The hex code is valid (#RRGGBB or shorthand). | The conversion targets CSS rgb(). | No alpha channel is modeled. - Sources: https://en.wikipedia.org/wiki/Web_colors | https://boringtoolskit.com/methodology/ ## Tool: Hexagon Calculator - URL: https://boringtoolskit.com/hexagon-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Hexagon calculator: area and perimeter of a regular hexagon. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Hiking Time Calculator - URL: https://boringtoolskit.com/hiking-time-calculator/ - Category: Sports - Evidence: catalogue - Description: Hiking time calculator: Naismith\u2019s rule for distance and elevation gain. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Holiday Pay Calculator - URL: https://boringtoolskit.com/holiday-pay-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Holiday pay calculator: time-and-a-half and double-time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Home Equity Calculator - URL: https://boringtoolskit.com/home-equity-calculator/ - Category: Real Estate - Evidence: catalogue - Description: Home equity calculator: your equity stake and loan-to-value ratio. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Horsepower Calculator - URL: https://boringtoolskit.com/horsepower-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Horsepower calculator: horsepower from torque and RPM (torque × RPM ÷ 5252). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Horsepower to kW Converter - URL: https://boringtoolskit.com/horsepower-kw-converter/ - Category: Converters - Evidence: catalogue - Description: Horsepower to kW converter: hp and kilowatts. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Hotel Stay Cost Calculator - URL: https://boringtoolskit.com/hotel-stay-cost-calculator/ - Category: Travel - Evidence: catalogue - Description: Hotel stay cost calculator: total trip hotel cost including taxes and resort fees, with per-person split. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Hours and Minutes Calculator - URL: https://boringtoolskit.com/hours-minutes-calculator/ - Category: Time & Work - Evidence: authored-methodology - Description: Add or subtract hours and minutes and show decimal-hour equivalents. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Converts each time to total minutes (hours × 60 + minutes), performs the addition or subtraction, then converts back to hours and minutes. - Assumptions: Values are durations, not clock times. | The 60-minute hour convention applies. | No date or midnight crossing is modeled. - Sources: https://en.wikipedia.org/wiki/Hour | https://boringtoolskit.com/methodology/ ## Tool: HP to Weight Ratio Calculator - URL: https://boringtoolskit.com/hp-to-weight-ratio-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Horsepower-to-weight calculator: power-to-weight in hp/lb and hp/ton for any car. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: HSA Tax Savings Calculator - URL: https://boringtoolskit.com/hsa-tax-savings-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: HSA tax savings calculator: what an HSA contribution saves you in federal income tax. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Humidity Index Calculator - URL: https://boringtoolskit.com/humidity-index-calculator/ - Category: Geography - Evidence: catalogue - Description: Humidity index calculator: humidex feels-like value from temperature and dew point. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Ideal Weight Calculator - URL: https://boringtoolskit.com/ideal-weight-calculator/ - Category: Health - Evidence: authored-methodology - Description: Estimate your ideal body weight using seven common formulas (Hamwi, Devine, Robinson, Miller, Broca, Lorentz, Peterson) plus a healthy BMI range. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: The tool reports the healthy BMI weight range (18.5–24.9 × height²) plus classic adult formulas in kg: Hamwi (male 48.0 + 2.7×in-over-60; female 45.5 + 2.2×in-over-60), Devine (male 50.0 + 2.3×in-over-60; female 45.5 + 2.3×in-over-60), Robinson (male 52.0 + 1.9×; female 49.0 + 1.7×), Miller (male 56.2 + 1.41×; female 53.1 + 1.36×), Broca (cm − 100), Lorentz ((cm − 100) − (cm − 150) ÷ (4 male / 2 female)), Peterson (2.2×targetBMI + 3.5×targetBMI×(heightM − 1.5)). - Assumptions: Height and sex are entered correctly. | The formulas are population reference standards. | Results are estimates, not medical advice. - Sources: https://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmicalc.htm | https://boringtoolskit.com/methodology/ ## Tool: Idle Cost Calculator - URL: https://boringtoolskit.com/idle-cost-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Idle cost calculator: fuel wasted while idling. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Image File Size Calculator - URL: https://boringtoolskit.com/image-file-size-calculator/ - Category: Photo & Video - Evidence: catalogue - Description: Image file size calculator: uncompressed size from pixel dimensions, bit depth, and color mode. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Image Resizer - URL: https://boringtoolskit.com/image-resize/ - Category: Converters - Evidence: authored-methodology - Description: Resize images without uploading to a server. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Rescales an image to target dimensions with a chosen fit: exact (stretch to W×H), inside (fit within bounds, preserving aspect ratio), or cover (fill bounds, cropping excess). - Assumptions: The browser canvas API is available. | The selected fit matches the intended use. | The original image file is preserved by the user. - Sources: https://en.wikipedia.org/wiki/Image_scaling | https://boringtoolskit.com/methodology/ ## Tool: Inches to CM Converter - URL: https://boringtoolskit.com/inches-to-cm-converter/ - Category: Converters - Evidence: catalogue - Description: Inches to centimeters converter: inches to cm, mm, meters, and feet. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Independent Events Calculator - URL: https://boringtoolskit.com/independent-events-calculator/ - Category: Statistics - Evidence: catalogue - Description: Independent events calculator: probability both events happen. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Inductance Calculator - URL: https://boringtoolskit.com/inductance-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Inductance calculator: inductance from inductive reactance and frequency. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Inflation Impact Calculator - URL: https://boringtoolskit.com/inflation-impact-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Model future cost and purchasing-power erosion from an editable constant annual inflation assumption. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Future cost = amount × (1 + rate)^years. Purchasing power = amount ÷ (1 + rate)^years. Price increase = amount × ((1 + rate)^years − 1). - Assumptions: A constant inflation rate over the period. | No interest or investment growth is modeled on the amount. | The CPI-like average reflects the user's spending. - Sources: https://en.wikipedia.org/wiki/Inflation | https://boringtoolskit.com/methodology/ ## Tool: Instagram Influencer Pricing Calculator - URL: https://boringtoolskit.com/instagram-influencer-pricing-calculator/ - Category: Social Media - Evidence: authored-methodology - Description: Calculate fair sponsored post rates from followers and engagement. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Suggested post price = followers × (engagement rate ÷ 100) × rate per engagement. - Assumptions: Engagement rate and rate-per-engagement are the user's inputs. | The price is a suggestion for a single sponsored post. | Deliverables (usage, exclusivity, story vs feed) often change actual pricing. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Insulation R-Value Calculator - URL: https://boringtoolskit.com/insulation-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Insulation R-value calculator: U-value conversion and rough annual savings estimate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Insulation R Value Calculator - URL: https://boringtoolskit.com/insulation-r-value-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Insulation R-value calculator: total R from layered materials. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Interest Only Loan Calculator - URL: https://boringtoolskit.com/interest-only-loan-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Interest-only loan calculator: IO payments then full amortization. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Interest Rate Calculator - URL: https://boringtoolskit.com/interest-rate-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Interest rate calculator: solve for the rate between present and future value. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Intermittent Fasting Calculator - URL: https://boringtoolskit.com/intermittent-fasting-calculator/ - Category: Health - Evidence: catalogue - Description: Intermittent fasting calculator: convert between eating windows and fasting hours. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Inventory Reorder Point Calculator - URL: https://boringtoolskit.com/inventory-reorder-point-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Calculate your inventory reorder point: lead time demand plus safety stock, then see whether current stock means reorder now. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Reorder point = (average daily sales × lead time in days) + safety stock. Days of stock on hand = current stock ÷ average daily sales. Order now if current stock ≤ reorder point. - Assumptions: Daily sales and lead time are reasonably stable. | Safety stock is set appropriately by the user. | No batch-discount or economic-order-quantity optimization is modeled. - Sources: https://en.wikipedia.org/wiki/Reorder_point | https://boringtoolskit.com/methodology/ ## Tool: Inverter Size Calculator - URL: https://boringtoolskit.com/inverter-size-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Inverter size calculator: continuous and surge sizing. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Investment Fee Calculator - URL: https://boringtoolskit.com/investment-fee-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Investment fee calculator: the real cost of annual fees on long-term returns. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Investment Growth Calculator - URL: https://boringtoolskit.com/investment-growth-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Investment growth calculator: future value with monthly contributions and compound interest. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Investment Return Calculator - URL: https://boringtoolskit.com/investment-return-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate total return and annualized (CAGR) return on an investment. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Total return = (ending value − starting value) ÷ starting value × 100, including any cash flow contributed. The calculator compares a starting and ending value along with extra contributions to produce a return figure. - Assumptions: Extra contributions are added on top of the starting value. | The return is over the full period, not annualized. | Fees and taxes are not included unless entered as cash flow. - Sources: https://www.investopedia.com/terms/r/returnoninvestment.asp | https://boringtoolskit.com/methodology/ ## Tool: Invoice Fee Calculator - URL: https://boringtoolskit.com/invoice-fee-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Invoice fee calculator: net after payment processing fees. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Invoice Generator - URL: https://boringtoolskit.com/invoice-gen/ - Category: Seller & Business - Evidence: authored-methodology - Description: Create a simple invoice and download as PDF. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Line totals = quantity × unit price; subtotal = Σ line totals; tax = subtotal × tax rate; total = subtotal + tax. The tool renders a printable invoice and supports multiple currencies. - Assumptions: The user enters accurate business and client details. | Line items are entered as description, qty, price. | The tax rate is a flat percentage of the subtotal. - Sources: https://en.wikipedia.org/wiki/Invoice | https://boringtoolskit.com/methodology/ ## Tool: Invoice Late Fee Calculator - URL: https://boringtoolskit.com/invoice-late-fee-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Estimate a simple or monthly-compounded late fee from invoice balance, rate, and overdue time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Simple: fee = balance × monthly rate × (days late ÷ 30.4). Compound: balance × ((1 + monthly rate)^months − 1). Months = days ÷ 30.437 (average). - Assumptions: The rate is stated in the invoice terms. | Days convert to months at 30.4 average days. | Local law permits the charged rate. - Sources: https://en.wikipedia.org/wiki/Late_fee | https://boringtoolskit.com/methodology/ ## Tool: IQR Calculator - URL: https://boringtoolskit.com/iqr-calculator/ - Category: Statistics - Evidence: catalogue - Description: IQR calculator: interquartile range from five values. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: IRR Calculator - URL: https://boringtoolskit.com/irr-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the internal rate of return from a series of cash flows. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: IRR is the discount rate r where the net present value of all cash flows equals zero: Σ cash_flow_t ÷ (1 + r)^t = 0. The tool solves for r by bisection between −99% and +1,000%. - Assumptions: Cash flows occur at the end of each period. | A single unique IRR exists (one sign change). | Interim cash flows are reinvested at the computed IRR. - Sources: https://www.investopedia.com/terms/i/irr.asp | https://boringtoolskit.com/methodology/ ## Tool: Jean Size Calculator - URL: https://boringtoolskit.com/jean-size-calculator/ - Category: Converters - Evidence: catalogue - Description: Jean size calculator: US to EU jean size conversion. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Jet Lag Calculator - URL: https://boringtoolskit.com/jet-lag-calculator/ - Category: Travel - Evidence: catalogue - Description: Jet lag calculator: expected recovery days from time-zone difference and direction of travel. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Jet Lag Adjustment Calculator - URL: https://boringtoolskit.com/jetlag-adjustment-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Jet lag adjustment calculator: estimated days to adjust after crossing time zones. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: JSON Formatter - URL: https://boringtoolskit.com/json-formatter/ - Category: Text & Developer Tools - Evidence: catalogue - Description: Format, validate, and pretty-print JSON instantly in your browser. Fix errors with a clear message and line pointer. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: KD Ratio Calculator - URL: https://boringtoolskit.com/kd-ratio-calculator/ - Category: Gaming - Evidence: catalogue - Description: KD ratio calculator: kill/death ratio from kills, deaths, and matches played. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Kelly Criterion Calculator - URL: https://boringtoolskit.com/kelly-criterion-calculator/ - Category: Gaming - Evidence: catalogue - Description: Kelly criterion calculator: optimal bet size from win probability and decimal odds. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Key Transposition Calculator - URL: https://boringtoolskit.com/key-transposition-calculator/ - Category: Music & Audio - Evidence: authored-methodology - Description: Transpose music between keys by semitones for any instrument or vocal range. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Semitone steps = (index of new key − index of old key + 12) mod 12, using the 12-note chromatic key set. - Assumptions: Keys use standard names and enharmonic equivalents (e.g. C# vs Db). | Transposition is measured in semitones from the original key. | The calculation moves up by default (a positive step count). - Sources: https://boringtoolskit.com/methodology/ ## Tool: Keyword Density Calculator - URL: https://boringtoolskit.com/keyword-density-calculator/ - Category: Text & Developer Tools - Evidence: catalogue - Description: Keyword density calculator: keyword share of a text. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Kinetic Energy Calculator - URL: https://boringtoolskit.com/kinetic-energy-calculator/ - Category: Physics - Evidence: authored-methodology - Description: Calculate the kinetic energy of a moving object from mass and velocity (KE = ½mv²). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Kinetic energy (KE) = ½ × mass × velocity². Units: joules (J) = kg · m²/s². - Assumptions: Mass is in kilograms and velocity in m/s. | The object's motion is translational (linear), not rotating. | Only positive mass and velocity are accepted. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Knitting Needle Converter - URL: https://boringtoolskit.com/knitting-needle-converter/ - Category: Converters - Evidence: catalogue - Description: Knitting needle converter: US, mm and UK needle sizes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Kombucha Brew Calculator - URL: https://boringtoolskit.com/kombucha-brew-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Kombucha brew calculator: tea, sugar and starter for a batch. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Late Fee Calculator - URL: https://boringtoolskit.com/late-fee-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Late fee calculator: penalty on an overdue invoice. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Law of Cosines Calculator - URL: https://boringtoolskit.com/law-of-cosines-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Law of cosines calculator: third side from two sides and angle. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Lawn Seed Calculator - URL: https://boringtoolskit.com/lawn-seed-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Lawn seed calculator: pounds of seed needed for your lawn area. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Lean Body Mass Calculator - URL: https://boringtoolskit.com/lean-body-mass-calculator/ - Category: Health - Evidence: catalogue - Description: Lean body mass calculator: LBM from weight and height (Boer). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Lease vs Buy Calculator - URL: https://boringtoolskit.com/lease-vs-buy-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Lease vs buy calculator: compare total lease cost against loan ownership over the same term. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: LED Savings Calculator - URL: https://boringtoolskit.com/led-savings-calculator/ - Category: Energy & Electrical - Evidence: authored-methodology - Description: Compare old and LED lighting energy cost, annual savings, and simple payback period. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Annual kWh = watts × bulb count × hours/day × 365 ÷ 1,000; savings = kWh reduction × rate; payback = upgrade cost ÷ annual savings. - Assumptions: Bulbs operate for the same number of hours at constant wattage. | Light output and quality are assumed comparable but not verified. | Replacement labor, lamp life, HVAC effects, rebates, and rate changes are excluded. - Sources: https://www.energystar.gov/products/lighting_fans/light_bulbs/learn_about_led_bulbs | https://www.eia.gov/energyexplained/electricity/use-of-electricity.php ## Tool: Length Converter - URL: https://boringtoolskit.com/length-converter/ - Category: Converters - Evidence: catalogue - Description: Length converter: miles, kilometers, meters, feet, inches, yards. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Light Year Distance Calculator - URL: https://boringtoolskit.com/light-year-distance-calculator/ - Category: Astronomy - Evidence: catalogue - Description: Light year distance calculator: convert light years to kilometers, miles, and AU. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Lighting Ratio Calculator - URL: https://boringtoolskit.com/lighting-ratio-calculator/ - Category: Photo & Video - Evidence: catalogue - Description: Lighting ratio calculator: convert main-to-fill stops to a lighting ratio and light falloff. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Limiting Reagent Calculator - URL: https://boringtoolskit.com/limiting-reagent-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Find the limiting reagent from two reactants and calculate product yield. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Moles of each reactant = mass ÷ molar mass. Equivalent = moles ÷ coefficient. The reactant with the smaller equivalent is the limiting reagent. - Assumptions: Both reactants' masses, molar masses, and coefficients are required. | The comparison uses the mole-per-coefficient equivalent. | The result identifies the limiting reagent, not the theoretical product mass. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Line Intersection Calculator - URL: https://boringtoolskit.com/line-intersection-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Line intersection calculator: where two lines cross. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Linear Equation Solver - URL: https://boringtoolskit.com/linear-equation-solver/ - Category: Everyday Calculators - Evidence: catalogue - Description: Linear equation solver: ax + b = c. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Linear Interpolation Calculator - URL: https://boringtoolskit.com/linear-interpolation-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Linear interpolation calculator: estimate y between two points. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Linear Regression Calculator - URL: https://boringtoolskit.com/linear-regression-calculator/ - Category: Statistics - Evidence: catalogue - Description: Linear regression calculator: slope, intercept, and R-squared for a least-squares line through paired data. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Liters to Ounces Converter - URL: https://boringtoolskit.com/liters-to-ounces/ - Category: Converters - Evidence: authored-methodology - Description: Convert liters to US or imperial fluid ounces with common-value reference tables. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: US fluid ounces = liters × 33.8140227. Imperial fluid ounces = liters × 35.1950797. 1 liter = 1,000 mL; 1 US cup = 236.6 mL. - Assumptions: The liter value is a volume measurement. | Standard US and imperial conversion factors are used. | The user selects the matching ounce system. - Sources: https://en.wikipedia.org/wiki/Litre | https://boringtoolskit.com/methodology/ ## Tool: Loan Comparison Calculator - URL: https://boringtoolskit.com/loan-comparison-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Compare monthly payment, total interest, and total cost for two fixed-rate loans. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Each loan's monthly payment = principal × [r × (1+r)^n] ÷ [(1+r)^n − 1], where r = annual rate ÷ 12 and n = term in months; total cost = monthly payment × n + fees. The calculator compares two loans by monthly payment, total cost, and interest. - Assumptions: Both loans share the same principal amount. | Each loan is a fixed-rate amortizing loan. | Fees are added to the total cost for comparison. - Sources: https://www.investopedia.com/terms/l/loan-comparison.asp | https://boringtoolskit.com/methodology/ ## Tool: Loan-to-Value Calculator - URL: https://boringtoolskit.com/loan-to-value-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate your loan-to-value (LTV) ratio. Enter loan amount and property value to see equity position and PMI risk. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Loan-to-value (LTV) = loan amount ÷ property value × 100. It expresses how much of a property is financed relative to its value; the remainder is your equity. - Assumptions: LTV is based on loan amount and current property value (or appraisal). | The calculator uses the values you enter — update them as value or balance changes. | Values below 0 are rejected; a value of 0 returns no result. - Sources: https://www.investopedia.com/terms/l/loan-to-value-ratio.asp | https://boringtoolskit.com/methodology/ ## Tool: Local Income Tax Calculator - URL: https://boringtoolskit.com/local-income-tax-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Local income tax calculator: which states levy county or city income taxes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Logarithm Calculator - URL: https://boringtoolskit.com/log-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the logarithm of a number in any base, or natural log. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: logₐ(x) = y means a^y = x. The tool computes ln(x) (natural log, base e), log₁₀(x) (common log), and log₂(x) (binary log). Input must be positive. - Assumptions: The input is a positive real number. | Standard definitions of ln, log₁₀, and log₂ are used. | Results are rounded to six decimal places. - Sources: https://www.mathsisfun.com/algebra/logarithms.html | https://boringtoolskit.com/methodology/ ## Tool: Logarithm Calculator - URL: https://boringtoolskit.com/logarithm-calculator/ - Category: Generators - Evidence: catalogue - Description: Logarithm calculator: log base 10, 2, e, or any custom base of a number, with the inverse check. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Long Division Calculator - URL: https://boringtoolskit.com/long-division-calculator/ - Category: School & Education - Evidence: catalogue - Description: Long division calculator: quotient and remainder with the steps shown. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Loot Box EV Calculator - URL: https://boringtoolskit.com/loot-box-ev-calculator/ - Category: Gaming - Evidence: catalogue - Description: Loot box expected value calculator: what a box is really worth from drop odds and item values. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Loot Drop Probability Calculator - URL: https://boringtoolskit.com/loot-drop-probability-calculator/ - Category: Gaming - Evidence: catalogue - Description: Loot drop probability calculator: chance of at least one drop after N attempts at a given drop rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Lottery Odds Calculator - URL: https://boringtoolskit.com/lottery-odds-calculator/ - Category: Gaming - Evidence: catalogue - Description: Lottery odds calculator: jackpot odds for any 5+1 or 6-number game. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Love Compatibility Calculator - URL: https://boringtoolskit.com/love-calculator/ - Category: Social Media - Evidence: catalogue - Description: Love compatibility calculator: a fun, deterministic name-based score. Entertainment only. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Luggage Volume Calculator - URL: https://boringtoolskit.com/luggage-volume-calculator/ - Category: Travel - Evidence: catalogue - Description: Luggage volume calculator: bag capacity in liters from dimensions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Lumber Calculator - URL: https://boringtoolskit.com/lumber-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Lumber calculator: board feet and total cost from nominal dimensions and length. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Lumens Calculator - URL: https://boringtoolskit.com/lumens-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Lumens calculator: light output needed for a room. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Luminance Brightness Calculator - URL: https://boringtoolskit.com/luminance-calculator/ - Category: Colors & Design - Evidence: catalogue - Description: Luminance calculator: relative luminance of a hex color and its perceived brightness. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Lump Sum Vs Dca Calculator - URL: https://boringtoolskit.com/lump-sum-vs-dca-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Compare investing a lump sum now versus dollar-cost averaging the same money monthly. See which strategy wins at your time horizon and return. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Macro Magnification Calculator - URL: https://boringtoolskit.com/macro-magnification-calculator/ - Category: Photo & Video - Evidence: catalogue - Description: Macro magnification calculator: reproduction ratio from extension tube and lens focal length. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Macro Planning Calculator - URL: https://boringtoolskit.com/macro-planning-calculator/ - Category: Health - Evidence: authored-methodology - Description: Allocate a user-selected adult calorie total across configurable protein, fat, and carbohydrate assumptions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Protein grams = body weight (kg) × protein target (g/kg). Fat grams = daily calories × fat % ÷ 9. Carbohydrate grams = (calories − protein×4 − fat×9) ÷ 4. - Assumptions: The user is an adult (18+ confirmation). | Protein and carbs are 4 cal/g; fat is 9 cal/g. | Targets are entered within healthy planning ranges. - Sources: https://en.wikipedia.org/wiki/Macronutrient | https://boringtoolskit.com/methodology/ ## Tool: Macro Split Calculator - URL: https://boringtoolskit.com/macro-split-calculator/ - Category: Health - Evidence: catalogue - Description: Macro split calculator: carbs from calories, protein, and fat targets. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Maintenance Calories Calculator - URL: https://boringtoolskit.com/maintenance-calories-calculator/ - Category: Health - Evidence: catalogue - Description: Maintenance calories calculator: calories to hold your weight (Mifflin-St Jeor). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Marathon Pace Predictor - URL: https://boringtoolskit.com/marathon-predictor/ - Category: Sports - Evidence: catalogue - Description: Marathon pace predictor: race-time predictions from a recent race using the Riegel formula. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Margin of Error Calculator - URL: https://boringtoolskit.com/margin-of-error-calculator/ - Category: Statistics - Evidence: catalogue - Description: Margin of error calculator: sampling error for a survey at a chosen confidence level. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Markdown Table Generator - URL: https://boringtoolskit.com/markdown-table-generator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Paste rows and columns of text and get a clean GitHub-flavored markdown (GFM) pipe table you can drop into READMEs and docs. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Parses delimited rows (CSV, tabs, pipes) and renders a GitHub-flavored Markdown table: a header row, a separator row, and body rows with pipe-aligned columns. - Assumptions: The first row is the header. | Rows have consistent column counts. | The target renderer supports GFM tables. - Sources: https://en.wikipedia.org/wiki/Markdown | https://boringtoolskit.com/methodology/ ## Tool: Market Cap Calculator - URL: https://boringtoolskit.com/market-cap-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Market cap calculator: company value from shares and price. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Market Value Calculator - URL: https://boringtoolskit.com/market-value-calculator/ - Category: Real Estate - Evidence: authored-methodology - Description: Estimate a property's market value from comparable price per square foot and quality adjustments. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Base value = property area × price per square foot. Estimated market value = base value × (1 + (quality adjustment + condition adjustment) ÷ 100). - Assumptions: Area and price-per-square-foot are entered by the user. | Quality and condition adjustments are percentages applied to the base. | The result is a rough estimate, not a formal appraisal. - Sources: https://www.investopedia.com/terms/m/marketvalue.asp | https://boringtoolskit.com/methodology/ ## Tool: Marketplace Advertising Break-Even Calculator - URL: https://boringtoolskit.com/marketplace-ad-break-even-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Calculate break-even ROAS and ACOS after product cost, marketplace fees, payment fees, fulfillment, shipping, returns allowance, and target profit. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Break-even ROAS = 1 ÷ gross margin %. At break-even, ad spend = margin dollars from the sale. The tool also shows the max ad cost per sale. - Assumptions: Margin is constant across sales. | Attribution of ad sales is accurate. | All ad spend is variable (no fixed fees). - Sources: https://en.wikipedia.org/wiki/Advertising | https://boringtoolskit.com/methodology/ ## Tool: Matrix Calculator - URL: https://boringtoolskit.com/matrix-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Add, subtract, or multiply 2x2 and 3x3 matrices. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Addition/subtraction: C[i][j] = A[i][j] ± B[i][j] (same size). Multiplication (n×n): C[i][j] = Σₖ A[i][k] × B[k][j]. The tool handles square matrices of size 2–4. - Assumptions: Matrices are square (n×n). | Entries are real numbers. | Multiplication uses standard row-by-column dot products. - Sources: https://en.wikipedia.org/wiki/Matrix_(mathematics) | https://boringtoolskit.com/methodology/ ## Tool: Matrix Determinant Calculator - URL: https://boringtoolskit.com/matrix-determinant-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: 3x3 matrix determinant calculator. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Matrix Transpose Calculator - URL: https://boringtoolskit.com/matrix-transpose-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Matrix transpose calculator: flip a 2x3 matrix. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Maximum Allowable Offer Calculator - URL: https://boringtoolskit.com/maximum-allowable-offer-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate the maximum allowable offer (MAO) for a flip using the 70% rule. Enter ARV, rehab, and holding costs. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Maximum allowable offer = after-repair value × 70% − rehabilitation cost (the 70% rule). The tool also computes the profit-based offer: ARV − rehab − holding costs − desired profit. - Assumptions: The 70% rule and profit-based offer are both computed from the same inputs. | Holding costs and desired profit are user-entered for the profit-based offer. | Actual values depend on accurate ARV and rehab estimates. - Sources: https://www.investopedia.com/terms/m/maximum-allowable-offer.asp | https://boringtoolskit.com/methodology/ ## Tool: Meal Prep Calculator - URL: https://boringtoolskit.com/meal-prep-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Meal prep calculator: batch quantity for meal prep. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Mean Arterial Pressure Calculator - URL: https://boringtoolskit.com/mean-arterial-pressure-calculator/ - Category: Health - Evidence: catalogue - Description: Mean arterial pressure calculator: MAP from systolic and diastolic. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Mean Median Mode Calculator - URL: https://boringtoolskit.com/mean-median-mode-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate mean, median, mode, range, sum, and count for any list of numbers. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Mean = sum ÷ count. Median = the middle value of the sorted list (or the average of the two middles for even counts). Mode = the most frequent value(s). - Assumptions: At least one number is entered. | Values are numeric. | Standard definitions apply for ties. - Sources: https://en.wikipedia.org/wiki/Average | https://boringtoolskit.com/methodology/ ## Tool: Meat Cooking Time Calculator - URL: https://boringtoolskit.com/meat-cooking-time-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Meat cooking time calculator: roast time by weight and type. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Meat Doneness Temperature Calculator - URL: https://boringtoolskit.com/meat-doneness-temperature-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Meat doneness temperature guide: target internal temperatures for beef, pork, chicken, and lamb. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Medicine Dosage Calculator - URL: https://boringtoolskit.com/medicine-dosage-calculator/ - Category: Health - Evidence: catalogue - Description: Medicine dosage calculator: dose from body weight and mg/kg dosing instructions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Meeting Cost Calculator - URL: https://boringtoolskit.com/meeting-cost-calculator/ - Category: Time & Work - Evidence: authored-methodology - Description: Estimate direct meeting labor cost, cost per minute, participant-hours, and annual recurring cost from editable compensation assumptions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Cost per meeting = (blended hourly cost × uplift) × duration hours. Annual cost = per-meeting cost × meetings per week × working weeks per year. - Assumptions: The uplift reflects benefits and overhead. | All attendees' time is fully occupied by the meeting. | Recurrence is consistent across the year. - Sources: https://en.wikipedia.org/wiki/Opportunity_cost | https://boringtoolskit.com/methodology/ ## Tool: Menstrual Cycle Calculator - URL: https://boringtoolskit.com/menstrual-cycle-calculator/ - Category: Health - Evidence: catalogue - Description: Menstrual cycle calculator: next period and estimated fertile window (private, no tracking stored). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Mercari Fee Calculator - URL: https://boringtoolskit.com/mercari-fee-calculator/ - Category: Seller & Business - Evidence: catalogue - Description: Mercari fee calculator: the flat 10% selling fee and your net. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Mercury Retrograde Calculator - URL: https://boringtoolskit.com/mercury-retrograde-calculator/ - Category: Astrology - Evidence: catalogue - Description: Mercury retrograde calculator: check if a date falls in a retrograde window, 2024-2030. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Meta Tag Generator - URL: https://boringtoolskit.com/meta-tags/ - Category: Text & Developer Tools - Evidence: authored-methodology - Description: Generate meta tags and social preview strings. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Generates an HTML head block from inputs: title, meta description, author, language, robots directive, canonical URL, and Open Graph tags (og:title, og:description, og:image, og:type) for social sharing. - Assumptions: The user supplies accurate page details. | OG image URLs are absolute and accessible. | Tags are placed in the HTML . - Sources: https://en.wikipedia.org/wiki/Meta_element | https://boringtoolskit.com/methodology/ ## Tool: Metabolic Age Calculator - URL: https://boringtoolskit.com/metabolic-age-calculator/ - Category: Health - Evidence: catalogue - Description: Metabolic age calculator: how your BMR compares to your age group. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Metric Prefix Converter - URL: https://boringtoolskit.com/metric-prefix-converter/ - Category: Converters - Evidence: catalogue - Description: Metric prefix converter: kilo, mega, giga, tera and friends. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Metronome BPM Calculator - URL: https://boringtoolskit.com/metronome-bpm-calculator/ - Category: Music & Audio - Evidence: authored-methodology - Description: Convert traditional tempo markings to BPM and see milliseconds per beat. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Tempo is set as beats per minute (BPM); the metronome converts BPM to a click interval between quarter-note beats (60,000 ÷ BPM ms) and supports standard tempo markings (larghissimo ~25 to prestissimo ~208). - Assumptions: BPM is the user's input; tempo markings are approximate ranges. | The audible click uses the Web Audio API and starts on explicit user action. | The default time signature is 4/4 unless changed. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Midpoint Calculator - URL: https://boringtoolskit.com/midpoint-calculator/ - Category: School & Education - Evidence: catalogue - Description: Midpoint calculator: the midpoint of a line segment between two points. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Mileage Log Calculator - URL: https://boringtoolskit.com/mileage-log-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Mileage log calculator: monthly and yearly mileage deductions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Mileage Reimbursement Calculator - URL: https://boringtoolskit.com/mileage-reimbursement-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Mileage reimbursement calculator: business miles at the IRS standard rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Modulo Calculator - URL: https://boringtoolskit.com/modulo-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Modulo calculator: remainder of a divided by b. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Molar Mass Calculator - URL: https://boringtoolskit.com/molar-mass-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Calculate the molar mass of a compound from its chemical formula. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Molar mass = Σ (atomic mass of each element × its count in the formula). - Assumptions: Atomic masses use the standard values embedded in the tool. | The formula is parsed element-by-element; unsupported elements are flagged. | The result is the molar mass of one formula unit. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Molarity Calculator - URL: https://boringtoolskit.com/molarity-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Calculate molarity from moles and volume, with solution prep details. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Molarity (M) = moles of solute ÷ volume of solution in liters. Concentration = molar mass × M (g/L). - Assumptions: Moles and volume are the user's inputs; volume must be positive. | If molar mass is given, the solution concentration is also reported in g/L. | The solution volume is in liters, not milliliters. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Molarity from Mass Calculator - URL: https://boringtoolskit.com/molarity-from-mass-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Convert grams of solute to molarity using molar mass and volume. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Moles = solute mass ÷ molar mass. Molarity = moles ÷ (volume in mL ÷ 1000). Concentration = mass ÷ (volume ÷ 1000) g/L. - Assumptions: Solute mass, molar mass, and solution volume (in mL) are required. | Molar mass and volume must be positive. | Volume is converted from mL to L internally. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Mole Calculator - URL: https://boringtoolskit.com/mole-calculator/ - Category: Chemistry - Evidence: catalogue - Description: Mole calculator: moles from mass and molar mass (chemistry). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Momentum Calculator - URL: https://boringtoolskit.com/momentum-calculator/ - Category: Physics - Evidence: authored-methodology - Description: Calculate linear momentum from mass and velocity (p = mv). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Momentum (p) = mass × velocity. Units: kg · m/s. - Assumptions: Mass is in kilograms and velocity in m/s. | Momentum is a vector along the direction of motion. | Positive values are required for both inputs. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Monitor Height Calculator - URL: https://boringtoolskit.com/monitor-height-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Monitor height calculator: screen position from eye level. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Moon Phase Calculator - URL: https://boringtoolskit.com/moon-phase-calculator/ - Category: Astronomy - Evidence: catalogue - Description: Moon phase calculator: current moon phase from the synodic cycle. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Morse Code Converter - URL: https://boringtoolskit.com/morse-code-converter/ - Category: Text & Developer Tools - Evidence: catalogue - Description: Morse code converter: text to Morse and back. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Mortgage Affordability Calculator - URL: https://boringtoolskit.com/mortgage-afford/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Find an affordable home price from income, debts, down payment, rate, taxes, insurance, HOA, and your DTI cap. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Affordable mortgage is solved by setting the monthly housing payment (principal + interest + property tax + insurance + HOA) against your gross monthly income and existing debts, using a target debt-to-income ratio (commonly 28% front-end, 36% back-end). - Assumptions: The target DTI (28% front-end / 36% back-end) is a standard guideline, not a guarantee. | Property tax, insurance, and HOA are included in the monthly payment. | The result is an estimate, not a pre-approval — a lender sets the final number. - Sources: https://www.investopedia.com/terms/m/mortgage.asp | https://boringtoolskit.com/methodology/ ## Tool: Mortgage Escrow Calculator - URL: https://boringtoolskit.com/mortgage-escrow-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Mortgage escrow calculator: monthly escrow payment from annual property tax and insurance. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Mortgage Overpayment Calculator - URL: https://boringtoolskit.com/mortgage-overpayment-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: See how extra monthly payments or a one-time lump sum cut years off a mortgage and save interest. Enter loan, rate, term, and overpayments for a private estimate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: An overpayment is any amount you pay above the required monthly mortgage payment. Every extra dollar goes straight to the principal, so it shortens the loan term and reduces the total interest you pay. - Assumptions: The overpayment is applied each month to the principal balance. | The loan is a fixed-rate amortizing mortgage. | Interest saved is compared to the base loan with no overpayments. - Sources: https://www.investopedia.com/terms/m/mortgage-payment.asp | https://boringtoolskit.com/methodology/ ## Tool: Mortgage Payment Calculator - URL: https://boringtoolskit.com/mortgage-payment-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate your monthly mortgage payment including principal, interest, taxes, and insurance. Enter loan amount, rate, and term for a full breakdown. Private. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Monthly principal and interest = P × r ÷ (1 − (1+r)^−n); all-in payment adds monthly tax, insurance, PMI estimate, and HOA. - Assumptions: Fixed rate and level principal-and-interest payments are assumed. | Property tax and insurance remain constant. | PMI cancellation rules, closing costs, utilities, and maintenance are not modeled. - Sources: https://www.consumerfinance.gov/owning-a-home/explore-rates/ | https://www.hud.gov/buying/loans ## Tool: Mortgage Payoff Calculator - URL: https://boringtoolskit.com/mortgage-payoff-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Mortgage payoff calculator: payoff date and interest saved with extra payments. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Mortgage Refinance Break-Even Calculator - URL: https://boringtoolskit.com/mortgage-refinance-break-even/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Compare old and new mortgage payments and estimate refinance break-even time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: New payment from the standard amortization formula at the new rate; monthly savings = old payment − new payment; break-even months = total closing costs ÷ monthly savings. - Assumptions: The balance stays the same (no cash-out). | The new loan amortizes over the entered term. | Closing costs are paid upfront and included in the analysis. - Sources: https://en.wikipedia.org/wiki/Refinancing | https://boringtoolskit.com/methodology/ ## Tool: Moving Average Calculator - URL: https://boringtoolskit.com/moving-average-calculator/ - Category: Statistics - Evidence: catalogue - Description: Moving average calculator: simple moving average of a series. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Mulch Calculator - URL: https://boringtoolskit.com/mulch-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Mulch calculator: cubic yards and bags for garden beds. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Mulch and Soil Calculator - URL: https://boringtoolskit.com/mulch-soil-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate cubic yards of mulch or soil from area, depth, and waste allowance. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Volume = length × width × depth (inches) ÷ 12 = cubic feet; cubic yards = cubic feet ÷ 27. Order volume = cubic yards × (1 + waste%). Bags: 1 cu ft bags = total × 27, 1.5 cu ft = total × 18, 2 cu ft = total × 13.5, 3 cu ft = total × 9. - Assumptions: The bed is rectangular and flat. | Depth is uniform across the bed. | Bulk volume is rounded to practical bag counts. - Sources: https://www.calculatorsoup.com/calculators/construction/mulch-calculator.php | https://boringtoolskit.com/methodology/ ## Tool: Music Interval Calculator - URL: https://boringtoolskit.com/music-interval-calculator/ - Category: Music & Audio - Evidence: catalogue - Description: Music interval calculator: interval name and semitone distance between two notes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Natural Log Calculator - URL: https://boringtoolskit.com/natural-log-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Natural log calculator: ln(x) and e^x. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Net Carbs Calculator - URL: https://boringtoolskit.com/net-carbs-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Net carbs calculator: carbs minus fiber and sugar alcohols. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Net Operating Income Calculator - URL: https://boringtoolskit.com/net-operating-income-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate net operating income (NOI) for a rental property. Enter rental income and operating expenses, before the mortgage. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Net operating income (NOI) = gross operating income (rent + other) − operating expenses (taxes + insurance + maintenance + management + utilities). NOI is the pre-financing, pre-tax profit of a property. - Assumptions: Income and expenses are entered annually. | Operating expenses exclude debt service and capital expenditures. | Vacancy and management fees should reflect realistic market rates. - Sources: https://www.investopedia.com/terms/n/noi.asp | https://boringtoolskit.com/methodology/ ## Tool: Net Present Value Calculator - URL: https://boringtoolskit.com/net-present-value-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Net present value calculator: NPV of a yearly cash flow at a discount rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Net Worth Calculator - URL: https://boringtoolskit.com/net-worth-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Add up your assets and liabilities to find your net worth. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Net worth = total assets − total liabilities. The calculator sums your entered asset lines (cash, investments, property) and subtracts your liabilities (loans, credit cards, mortgage balance) to give a single balance-sheet number. - Assumptions: Assets and liabilities are entered by the user as 'label, amount' lines. | Asset values are current market values (not what you paid). | The result is a point-in-time snapshot. - Sources: https://www.investopedia.com/terms/n/networth.asp | https://boringtoolskit.com/methodology/ ## Tool: Normal Distribution Probability Calculator - URL: https://boringtoolskit.com/normal-distribution-probability-calculator/ - Category: Statistics - Evidence: catalogue - Description: Normal distribution probability calculator: area under the curve for a value, above a value, or between two values. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Nth Root Calculator - URL: https://boringtoolskit.com/nth-root-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Nth root calculator: the n-th root of a number. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Numbers to Words Converter - URL: https://boringtoolskit.com/numbers-to-words/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Convert any whole number into English words , for checks, contracts, and homework. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Converts an integer (0–999,999,999,999) into English words using the standard grouping by thousands. - Assumptions: US short-scale naming applies. | Whole numbers only within the stated range. | Standard English hyphenation rules are used. - Sources: https://en.wikipedia.org/wiki/English_numerals | https://boringtoolskit.com/methodology/ ## Tool: Numerology Life Path Calculator - URL: https://boringtoolskit.com/numerology-life-path-calculator/ - Category: Astrology - Evidence: catalogue - Description: Numerology life path calculator: reduce a birth date to its life path number, master numbers kept. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Numerology Name Number Calculator - URL: https://boringtoolskit.com/numerology-name-number-calculator/ - Category: Astrology - Evidence: catalogue - Description: Numerology name number calculator: Pythagorean letter values for any name, entertainment only. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Octal Converter - URL: https://boringtoolskit.com/octal-converter/ - Category: Converters - Evidence: catalogue - Description: Octal converter: decimal, binary, octal and hex. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Odds Ratio Calculator - URL: https://boringtoolskit.com/odds-ratio-calculator/ - Category: Statistics - Evidence: catalogue - Description: Odds ratio calculator: association from a 2x2 table. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Ohm's Law Calculator - URL: https://boringtoolskit.com/ohms-law-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate voltage, current, resistance, or power using Ohm's law. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Ohm's law: V = I × R (voltage = current × resistance). Derived: I = V ÷ R, R = V ÷ I. Power: P = V × I (watts). - Assumptions: The component is ohmic (linear resistance). | DC or RMS AC values are used. | Temperature effects on resistance are ignored. - Sources: https://en.wikipedia.org/wiki/Ohm%27s_law | https://boringtoolskit.com/methodology/ ## Tool: On Call Pay Calculator - URL: https://boringtoolskit.com/on-call-pay-calculator/ - Category: Time & Work - Evidence: catalogue - Description: On call pay calculator: compensation for on-call hours. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: One Rep Max Calculator - URL: https://boringtoolskit.com/one-rep-max-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate your one-rep max from a submaximal lift. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Estimated one-rep max (Epley formula): 1RM = weight × (1 + reps ÷ 30). 95% of max ≈ 1RM × 0.95. - Assumptions: The set was performed to near failure with good form. | The lift is a compound barbell movement. | The trainee is experienced enough to train near maximal loads. - Sources: https://www.acefitness.org/resources/everyone/tools-calculators/ | https://boringtoolskit.com/methodology/ ## Tool: Orbital Period Calculator - URL: https://boringtoolskit.com/orbital-period-calculator/ - Category: Astronomy - Evidence: catalogue - Description: Orbital period calculator: circular orbit period around Earth from altitude (Kepler). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Order of Operations Calculator (PEMDAS) - URL: https://boringtoolskit.com/order-of-operations-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Evaluate math expressions with the correct order of operations (PEMDAS): parentheses, exponents, multiplication and division, then addition and subtraction. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: The calculator tokenizes the expression and evaluates it with standard precedence: parentheses group first, exponents next, multiplication and division left to right, then addition and subtraction left to right. - Assumptions: Interpretation uses standard arithmetic precedence (PEMDAS). | Division by zero and unbalanced parentheses are reported as invalid. | Only numbers and the operators + − × ÷ ( ) are accepted. - Sources: /methodology/ ## Tool: Outlier Calculator - URL: https://boringtoolskit.com/outlier-calculator/ - Category: Statistics - Evidence: catalogue - Description: Outlier calculator: flag outliers by the 1.5x IQR rule. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Oven Conversion Calculator - URL: https://boringtoolskit.com/oven-conversion-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Oven conversion calculator: conventional to convection. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Oven Temperature Converter - URL: https://boringtoolskit.com/oven-temperature-converter/ - Category: Food & Cooking - Evidence: catalogue - Description: Oven temperature converter: Fahrenheit, Celsius, and UK gas marks. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Overtime Calculator - URL: https://boringtoolskit.com/overtime-calculator/ - Category: Time & Work - Evidence: authored-methodology - Description: Estimate regular and overtime pay with editable thresholds and overtime multipliers. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Regular hours = min(worked, threshold). Overtime hours = max(0, worked − threshold). Pay = regular × rate + overtime × rate × multiplier (typically 1.5×). - Assumptions: The employee is non-exempt. | One overtime threshold applies. | The multiplier matches the employer's policy (1.5× typical). - Sources: https://en.wikipedia.org/wiki/Overtime | https://boringtoolskit.com/methodology/ ## Tool: Ovulation Calculator - URL: https://boringtoolskit.com/ovulation-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate your fertile window and ovulation date based on cycle length and last period. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Ovulation date = period start + (cycle length − 14). Fertile window = ovulation − 5 days to ovulation + 1 day. Next period = period start + cycle length. Based on the standard assumption that ovulation occurs ~14 days before the next period. - Assumptions: Ovulation occurs about 14 days before the next period. | The entered cycle length is a stable average. | Luteal phase length is the typical 14 days. - Sources: https://www.acog.org/womens-health/faqs/fertility-awareness-based-methods-of-family-planning | https://boringtoolskit.com/methodology/ ## Tool: P Value Calculator - URL: https://boringtoolskit.com/p-value-calculator/ - Category: Statistics - Evidence: catalogue - Description: P value calculator: two-tailed p-value from a z-score. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pace Calculator - URL: https://boringtoolskit.com/pace-calculator/ - Category: Health - Evidence: authored-methodology - Description: Calculate your running pace per km or mile from distance and time, plus speed and predicted race times. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Pace = total time ÷ distance. Total time = hours×3600 + minutes×60 + seconds (seconds). Pace per unit = total seconds ÷ distance, formatted as mm:ss per mile or kilometer. - Assumptions: The pace is constant across the distance. | Time and distance are entered accurately. | The result is an average, not instantaneous, pace. - Sources: https://www.calculatorsoup.com/calculators/health/pace-calculator.php | https://boringtoolskit.com/methodology/ ## Tool: Packing Weight Calculator - URL: https://boringtoolskit.com/packing-weight-calculator/ - Category: Travel - Evidence: catalogue - Description: Packing weight calculator: total luggage weight from item counts and typical weights. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Paint Calculator - URL: https://boringtoolskit.com/paint-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Estimate how many gallons of paint you need for walls, doors, and trim. Covers two coats and accounts for waste. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Paint Cost Per Square Foot Calculator - URL: https://boringtoolskit.com/paint-cost-per-square-foot/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate paint cost per square foot or the total to paint a room from your own rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Material cost per sq ft = paint rate per sq ft × number of coats. Total = area × per-sq-ft cost + labor. - Assumptions: Flat, accessible surfaces. | Coverage matches the paint's rated rate. | Prep work is included in labor or separate. - Sources: https://en.wikipedia.org/wiki/House_painting | https://boringtoolskit.com/methodology/ ## Tool: Paint Coverage Calculator - URL: https://boringtoolskit.com/paint-coverage-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate paintable wall area and gallons needed after subtracting doors and windows. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Gross wall area = perimeter × wall height. Openings = doors × 20 + windows × 15 sq ft. Paintable area = max(0, gross − openings). Coated area = paintable area × coats. Gallons = ceil(coated area ÷ coverage per gallon). - Assumptions: Openings average 20 sq ft per door and 15 sq ft per window. | A gallon covers the entered coverage (350 sq ft is typical). | Walls are smooth and already primed. - Sources: https://www.bobvila.com/articles/how-much-paint-do-i-need/ | https://boringtoolskit.com/methodology/ ## Tool: Parallelogram Area Calculator - URL: https://boringtoolskit.com/parallelogram-area-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Parallelogram area calculator: area from base and height. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Area = base × height (the perpendicular height, not the side length). - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Parking Cost Calculator - URL: https://boringtoolskit.com/parking-cost-calculator/ - Category: Travel - Evidence: catalogue - Description: Parking cost calculator: daily vs monthly pass comparison for commuters. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Parlay Odds Calculator - URL: https://boringtoolskit.com/parlay-odds-calculator/ - Category: Gaming - Evidence: catalogue - Description: Parlay odds calculator: combined odds and implied probability for multi-leg bets. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: NFL Passer Rating Calculator - URL: https://boringtoolskit.com/passer-rating-calculator/ - Category: Sports - Evidence: catalogue - Description: NFL passer rating calculator: QB rating from attempts, completions, yards, touchdowns, and interceptions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Password Generator - URL: https://boringtoolskit.com/password-generator/ - Category: Text & Developer Tools - Evidence: authored-methodology - Description: Generate strong random passwords with configurable length and character sets, with entropy and strength rating. Local and private. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Passwords are generated by randomly selecting characters from the enabled sets (lowercase, uppercase, digits, symbols), length 6–64. Entropy = length × log₂(character-set size): a 16-character password from 94 printable characters has ≈ 105 bits of entropy. - Assumptions: Generation uses a cryptographically random source in the browser. | The password is stored and managed securely by the user. | Entropy assumes random, uniform character selection. - Sources: https://pages.nist.gov/800-63-3/sp800-63b.html | https://boringtoolskit.com/methodology/ ## Tool: Patio Paver Calculator - URL: https://boringtoolskit.com/patio-paver-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Patio paver calculator: pavers needed with waste. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Paver Calculator - URL: https://boringtoolskit.com/paver-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate paver count, base aggregate, bedding sand, waste, and optional paver cost. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Pavers = ceiling(project area ÷ paver face area × (1 + waste)); base and sand volume = area × depth ÷ 27. - Assumptions: Paver dimensions are nominal face dimensions and joints are not separately modeled. | Base and bedding depths are uncompacted planning inputs. | Edging, joint sand, drainage, labor, and delivery are excluded. - Sources: https://www.cmha.org/ | https://www.nist.gov/pml/owm/metric-si/si-units ## Tool: Salary Raise Calculator - URL: https://boringtoolskit.com/pay-raise-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Convert a pay raise into new annual, monthly, weekly, and hourly compensation. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Raise amount = current pay × raise percentage; new pay = current pay + raise amount. - Assumptions: Current pay is treated as annual gross compensation. | Hourly equivalent uses the entered paid weeks and hours. | Taxes, benefits, bonuses, and inflation are excluded. - Sources: https://www.bls.gov/ncs/ | https://www.dol.gov/general/topic/wages ## Tool: Paycheck After Tax Calculator - URL: https://boringtoolskit.com/paycheck-calc/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate 2026 federal and FICA withholding with clearly labeled state planning estimates. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Gross pay = hours × rate (plus overtime) or salary. Deductions: federal income tax (standard deduction and brackets), FICA (Social Security 6.2% + Medicare 1.45%), and state income tax by state. Net pay = gross − deductions. - Assumptions: Federal standard deduction and current brackets apply. | No pre-tax benefits (401k, insurance) are deducted. | The state tax table reflects the selected state's rates. - Sources: https://en.wikipedia.org/wiki/Paycheck | https://boringtoolskit.com/methodology/ ## Tool: Payload and Towing Calculator - URL: https://boringtoolskit.com/payload-towing-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Payload and towing calculator: remaining payload from GVWR, curb weight, passengers, and cargo. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: PayPal & Stripe Fee Calculator - URL: https://boringtoolskit.com/payment-fee-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Calculate PayPal and Stripe fees, net proceeds, or the amount to charge. Use editable presets for Stripe 2.9% + $0.30 and PayPal 3.49% + $0.49. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Processing fee = amount × percentage fee + fixed fee. The calculator applies a percentage and a fixed per-transaction cost (with presets for Stripe and PayPal) to a sale amount, plus any custom fee, to show what the seller nets. - Assumptions: Fee is a percentage of the sale plus a fixed per-transaction cost. | Presets reflect standard online rates (Stripe, PayPal) — your actual rate may vary. | The result is the merchant's net after the processing fee. - Sources: https://www.investopedia.com/terms/p/payment-fee.asp | https://boringtoolskit.com/methodology/ ## Tool: Payment Terms Generator - URL: https://boringtoolskit.com/payment-terms-generator/ - Category: Generators - Evidence: authored-methodology - Description: Draft plain-language payment terms for invoices, quotes, retainers, deposits, late fees, and due dates. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Composes a payment terms clause from structured inputs: deposit %, due window, late fee, payment methods, and scope of services. Output is a plain-text terms paragraph ready to paste into contracts or invoices. - Assumptions: The user sets terms they intend to enforce. | The clause is a plain-English template. | Local legal requirements are checked separately. - Sources: https://en.wikipedia.org/wiki/Invoice | https://boringtoolskit.com/methodology/ ## Tool: Payout Ratio Calculator - URL: https://boringtoolskit.com/payout-ratio-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Payout ratio calculator: dividends as a share of earnings. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: PayPal Fee Calculator - URL: https://boringtoolskit.com/paypal-fee-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate estimated PayPal fees, net proceeds, or the amount to charge for a target net. Starts with an editable 3.49% + $0.49 planning preset. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Fee = amount × percentage rate + fixed fee. Net = amount − fee. Rates vary by transaction type (goods & services ~2.99% + $0.49 in the US). - Assumptions: The standard rate for the user's country applies. | No currency conversion is involved. | The transaction is goods & services. - Sources: https://en.wikipedia.org/wiki/PayPal | https://boringtoolskit.com/methodology/ ## Tool: PDF to JPG Converter - URL: https://boringtoolskit.com/pdf-to-jpg/ - Category: Converters - Evidence: authored-methodology - Description: Convert PDF pages to images directly in your browser. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Renders a chosen PDF page to a JPG image at a scale multiplier (1–6×). Higher scale means larger pixel dimensions; the page number selects which page is rendered. All processing happens locally in your browser. - Assumptions: The browser supports built-in PDF rendering. | The user selects the correct page and scale. | Output quality matches the source PDF's content. - Sources: https://en.wikipedia.org/wiki/Portable_Document_Format | https://boringtoolskit.com/methodology/ ## Tool: PE Ratio Calculator - URL: https://boringtoolskit.com/pe-ratio-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: PE ratio calculator: price-to-earnings from price and EPS. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pension Calculator - URL: https://boringtoolskit.com/pension-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate a monthly pension benefit from salary, years of service, and a multiplier. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Annual benefit = multiplier × years of service × final average salary. Monthly benefit = annual benefit ÷ 12; income replacement ratio = annual benefit ÷ salary × 100. - Assumptions: The plan uses a straight multiplier × years × final salary formula. | No early-retirement reduction or survivor election is applied. | The entered multiplier matches your plan's benefit formula. - Sources: https://www.investopedia.com/terms/p/pensionplan.asp | https://boringtoolskit.com/methodology/ ## Tool: Percent Difference Calculator - URL: https://boringtoolskit.com/percent-difference-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Percent difference calculator: relative difference between two values. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Percent difference = |a − b| ÷ ((a + b)/2) × 100. - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Percent Solution Calculator - URL: https://boringtoolskit.com/percent-solution-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Calculate percent solution concentration by weight or volume. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Percent w/v = (solute mass ÷ solution volume in mL) × 100. Percent w/w = (solute mass ÷ solution mass) × 100. - Assumptions: w/v uses solution volume (mL); w/w uses total solution mass (g). | Total mass or volume must be positive. | The percent basis (w/v vs w/w) changes the meaning of the concentration. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Percent Yield Calculator - URL: https://boringtoolskit.com/percent-yield-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Calculate percent yield from actual and theoretical yield. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Percent yield = (actual yield ÷ theoretical yield) × 100. - Assumptions: Actual and theoretical yield are in the same units. | Theoretical yield must be positive. | A yield above 100% indicates impurities or measurement error, not a real excess. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Percentage Calculator - URL: https://boringtoolskit.com/percentage-calc/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate percentages, increases, and changes instantly. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Three modes: (1) X% of Y = X ÷ 100 × Y; (2) X as a percent of Y = X ÷ Y × 100; (3) percent change = (new − old) ÷ old × 100. - Assumptions: The selected mode matches the question. | Values are non-negative except where change allows negatives. | Relative change is measured from the old value. - Sources: https://en.wikipedia.org/wiki/Percentage | https://boringtoolskit.com/methodology/ ## Tool: Percentage Change Calculator - URL: https://boringtoolskit.com/percentage-change-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Percentage change calculator: the % increase or decrease between two values. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Percent change = (new − old) ÷ |old| × 100. - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Percentage Error Calculator - URL: https://boringtoolskit.com/percentage-error-calculator/ - Category: Statistics - Evidence: catalogue - Description: Percentage error calculator: measured vs true value as a percentage, for labs and measurements. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Percentage Markup Calculator - URL: https://boringtoolskit.com/percentage-markup-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Enter a cost and markup percentage to get the selling price, markup amount, and profit margin. What is a 15% markup on $85? It is $97.75. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Markup = (selling price − cost) ÷ cost × 100. Margin = (selling price − cost) ÷ selling price × 100. The tool converts between the two. - Assumptions: Cost is the total product cost. | Selling price is before tax and discounts. | The conversion follows standard formulas. - Sources: https://en.wikipedia.org/wiki/Markup_(business) | https://boringtoolskit.com/methodology/ ## Tool: Percentile Calculator - URL: https://boringtoolskit.com/percentile-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Find the value at any percentile in a data set, or the percentile rank of a given value. Enter your data and the percentile you need. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: The pth percentile is the value at rank ceil((p ÷ 100) × n), clamped between 1 and n, of the sorted data set. - Assumptions: The percentile value must be between 1 and 99. | The tool uses the nearest-rank method on the sorted data. | At least one data point is required. - Sources: https://www.itl.nist.gov/div898/handbook/ | https://boringtoolskit.com/methodology/ ## Tool: Period Cycle Calculator - URL: https://boringtoolskit.com/period-cycle-calculator/ - Category: Health - Evidence: catalogue - Description: Period cycle calculator: estimate the next period and fertile window from cycle length. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Permutation Combination Calculator - URL: https://boringtoolskit.com/permutation-combination-calculator/ - Category: Statistics - Evidence: catalogue - Description: Permutation and combination calculator: nPr and nCr. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Permutations Calculator (nPr) - URL: https://boringtoolskit.com/permutations-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the number of permutations (nPr) of arranging r items from n, with the formula explained. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: nPr = n! ÷ (n − r)! = n × (n − 1) × … × (n − r + 1). The calculator multiplies consecutive terms and guards against overflow. - Assumptions: r must be between 0 and n, and n at least 1. | Order matters (ordered arrangement). | Result is an integer; overflow is reported as an invalid input. - Sources: /methodology/ ## Tool: Personal Loan Calculator - URL: https://boringtoolskit.com/personal-loan-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Personal loan calculator: monthly payment with origination fee. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pet Annual Cost Calculator - URL: https://boringtoolskit.com/pet-annual-cost-calculator/ - Category: Pets - Evidence: catalogue - Description: Pet annual cost calculator: yearly dog or cat expenses. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: pH Calculator - URL: https://boringtoolskit.com/ph-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Calculate pH, pOH, and hydrogen/hydroxide ion concentration for acids and bases. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: pH = −log₁₀[H⁺]. pOH = 14 − pH. [OH⁻] = 10^(−pOH). - Assumptions: Hydrogen ion concentration is entered in mol/L. | The calculation assumes aqueous solution at 25°C. | A pH of 7 is neutral, below 7 acidic, above 7 basic. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Pipe Sizing Calculator - URL: https://boringtoolskit.com/pipe-sizing-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Pipe sizing calculator: minimum pipe diameter for a target flow rate and velocity. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pipe Volume Calculator - URL: https://boringtoolskit.com/pipe-volume-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Pipe volume calculator: volume of water in a pipe from diameter and length. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pizza Dough Calculator - URL: https://boringtoolskit.com/pizza-dough-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Pizza dough calculator: flour, water, salt, yeast by baker's percentage. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Planetary Weight Calculator - URL: https://boringtoolskit.com/planetary-weight-calculator/ - Category: Astronomy - Evidence: catalogue - Description: Planetary weight calculator: your weight on other planets and moons from surface gravity ratios. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Plank Test Calculator - URL: https://boringtoolskit.com/plank-test-calculator/ - Category: Sports - Evidence: catalogue - Description: Plank test calculator: core endurance rating from hold time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Poisson Probability Calculator - URL: https://boringtoolskit.com/poisson-probability-calculator/ - Category: Statistics - Evidence: catalogue - Description: Poisson probability calculator: probability of exactly k events given a mean rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pollen Forecast Calculator - URL: https://boringtoolskit.com/pollen-forecast-calculator/ - Category: Health - Evidence: catalogue - Description: Pollen forecast calculator: current pollen levels for any city. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Polynomial Evaluator - URL: https://boringtoolskit.com/polynomial-evaluator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Polynomial evaluator: evaluate ax² + bx + c at x. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pomodoro Timer - URL: https://boringtoolskit.com/pomodoro-timer/ - Category: Time & Work - Evidence: authored-methodology - Description: Focus with work and break intervals — set focus minutes, short and long breaks, and run the Pomodoro timer in your browser. Free, no signup. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Work in 25-minute focus blocks separated by 5-minute breaks; after 4 blocks, take a longer break (15–30 minutes). Cycles are configurable in the tool. - Assumptions: The user works on one task per focus block. | Breaks are taken away from the screen. | Block lengths are adjustable to the task. - Sources: https://en.wikipedia.org/wiki/Pomodoro_Technique | https://boringtoolskit.com/methodology/ ## Tool: Pond Volume Calculator - URL: https://boringtoolskit.com/pond-volume-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Pond volume calculator: gallons in a rectangular pond. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pool Volume Calculator - URL: https://boringtoolskit.com/pool-volume-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Pool volume calculator: gallons in a rectangular, round, or oval pool. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Population Density Calculator - URL: https://boringtoolskit.com/population-density-calculator/ - Category: Geography - Evidence: catalogue - Description: Population density calculator: people per square kilometer or mile from population and area. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Portion Size Calculator - URL: https://boringtoolskit.com/portion-size-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Portion size calculator: scale a recipe's serving size to a new number of portions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Poshmark Fee Calculator - URL: https://boringtoolskit.com/poshmark-fee-calculator/ - Category: Seller & Business - Evidence: catalogue - Description: Poshmark fee calculator: selling fees and net for any sale price. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Post Frequency Calculator - URL: https://boringtoolskit.com/post-frequency-calculator/ - Category: Social Media - Evidence: authored-methodology - Description: Plan a sustainable social posting cadence across platforms. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Total posts = posts per week × weeks. Estimated reach = total posts × average views per post. Monthly views ≈ posts/week × 4.333 × avg views. - Assumptions: Posts per week, average views, and weeks are the user's estimates. | Views per post are assumed stable across the period. | The metric is a reach proxy; it does not measure followers, subscriptions, or engagement. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Potential Energy Calculator - URL: https://boringtoolskit.com/potential-energy-calculator/ - Category: Physics - Evidence: authored-methodology - Description: Calculate gravitational potential energy from mass, height, and gravity (PE = mgh). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Gravitational potential energy (PE) = mass × height × gravity. Gravity defaults to 9.81 m/s². Units: joules (J). - Assumptions: Mass is in kilograms and height in meters. | Gravity defaults to Earth's 9.81 m/s² and is editable. | The reference height is the ground level (PE = 0 at the reference floor). - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Power Factor Calculator - URL: https://boringtoolskit.com/power-factor-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Power factor calculator: PF from real watts and apparent volt-amps. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pregnancy Calculator - URL: https://boringtoolskit.com/pregnancy-calculator/ - Category: Health - Evidence: authored-methodology - Description: Estimate your pregnancy due date and current week from your last period, conception date, or a known due date. Private, no account. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Due date = LMP + 280 days (40 weeks). Key milestones: conception ≈ LMP + 14 days; the estimate tracks weeks of pregnancy from the LMP and flags the current trimester (first: 0–13 weeks, second: 14–27, third: 28+). - Assumptions: A regular 28-day cycle with ovulation at day 14. | A single pregnancy. | The entered LMP is accurate. - Sources: https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2017/05/methods-for-estimating-the-due-date | https://boringtoolskit.com/methodology/ ## Tool: Pregnancy Due Date Calculator - URL: https://boringtoolskit.com/pregnancy-due-date-calculator/ - Category: Health - Evidence: catalogue - Description: Pregnancy due date calculator: estimate the due date from the first day of the last menstrual period. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pregnancy Weight Gain Calculator - URL: https://boringtoolskit.com/pregnancy-weight-gain-calculator/ - Category: Health - Evidence: catalogue - Description: Pregnancy weight gain calculator: IOM recommended ranges by BMI and week. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Present Value Calculator - URL: https://boringtoolskit.com/present-value-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Find what a future lump sum is worth today at a given discount rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Present value = future amount ÷ (1 + discount rate ÷ compounds)^(compounds × years). The discount is the difference between the future amount and its present value. - Assumptions: A constant discount rate over the full period. | Compounding at the selected frequency. | No taxes, inflation adjustments, or risk premiums beyond the chosen rate. - Sources: https://www.investopedia.com/terms/p/presentvalue.asp | https://boringtoolskit.com/methodology/ ## Tool: Pressure Calculator - URL: https://boringtoolskit.com/pressure-calculator/ - Category: Physics - Evidence: authored-methodology - Description: Calculate pressure from force and area (P = F/A) with pascal and psi results. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Pressure (P) = force ÷ area. Units: pascals (Pa) = N/m². Conversions: kPa = Pa ÷ 1000; psi = Pa × 0.000145038. - Assumptions: Force is in newtons and area in square meters. | Pressure is assumed evenly distributed over the area. | Positive values are required for both inputs. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Pressure Converter - URL: https://boringtoolskit.com/pressure-converter/ - Category: Converters - Evidence: catalogue - Description: Pressure converter: psi, bar, kPa, atm. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pressure Cooker Time Calculator - URL: https://boringtoolskit.com/pressure-cooker-time-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Pressure cooker time calculator: cooking times for common foods. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Price Increase Impact Calculator - URL: https://boringtoolskit.com/price-increase-impact-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Compare revenue and contribution after a price change and expected unit-volume response. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: New volume = current units × (1 + volume change %). Current contribution = (current price − variable cost) × current units. New contribution = (new price − variable cost) × new volume. The tool compares revenue and profit impact. - Assumptions: Variable cost per unit is constant. | Fixed costs don't change with volume in the modeled range. | The volume change estimate is realistic. - Sources: https://en.wikipedia.org/wiki/Price_elasticity_of_demand | https://boringtoolskit.com/methodology/ ## Tool: Price Per Square Foot Calculator - URL: https://boringtoolskit.com/price-per-square-foot/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Work out price per square foot, or back into total price or area from a rate and budget. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Price per sq ft = price ÷ area. The tool also works backward: total price = area × rate. - Assumptions: The area is the living area (not lot). | Comparisons use similar property types. | The rate reflects the local market. - Sources: https://en.wikipedia.org/wiki/Price_per_square_foot | https://boringtoolskit.com/methodology/ ## Tool: Price-to-Rent Ratio Calculator - URL: https://boringtoolskit.com/price-to-rent-ratio-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate the price-to-rent ratio. Enter home price and annual rent to see the classic buy-vs-rent market signal. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Price-to-rent ratio = property price ÷ annual rent. Annual rent is monthly rent × 12. The ratio tells you whether buying or renting is the better financial move in a market. - Assumptions: Annual rent is monthly rent × 12. | The ratio is a market comparison, not a per-property buy decision. | Value and rent are the only inputs — investing costs are not modeled. - Sources: https://www.investopedia.com/terms/p/price-to-rent-ratio.asp | https://boringtoolskit.com/methodology/ ## Tool: Prime Checker - URL: https://boringtoolskit.com/prime-checker/ - Category: Everyday Calculators - Evidence: catalogue - Description: Prime checker: is a number prime, with factors. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Prime Factorization Calculator - URL: https://boringtoolskit.com/prime-factorization-calculator/ - Category: School & Education - Evidence: catalogue - Description: Prime factorization calculator: prime factors with exponents for any number. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Print Size Calculator - URL: https://boringtoolskit.com/print-size-calculator/ - Category: Photo & Video - Evidence: catalogue - Description: Print size calculator: compute print dimensions and PPI from pixel dimensions and physical print size. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Printable Calendar - URL: https://boringtoolskit.com/printable-calendar/ - Category: Time & Work - Evidence: authored-methodology - Description: Create a clean six-week monthly calendar with Sunday or Monday week starts, then print it or save it as a PDF. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Generates a month grid calendar for any year/month with correct weekday alignment, ready to print or save. - Assumptions: The Gregorian calendar applies. | Weeks start on Sunday by default. | No holidays are pre-filled. - Sources: https://en.wikipedia.org/wiki/Calendar | https://boringtoolskit.com/methodology/ ## Tool: Prize Wheel Spinner - URL: https://boringtoolskit.com/prize-wheel/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Spin a prize wheel to randomly choose a winner from segments you add. Local browser randomness, no upload. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Spins a segmented wheel with a physics-based decelerating rotation and unbiased random landing. Each segment's win probability equals its share of the wheel. - Assumptions: Segments are equally weighted by default. | The RNG is unbiased for practical purposes. | Each spin is independent. - Sources: https://en.wikipedia.org/wiki/Random_number_generation | https://boringtoolskit.com/methodology/ ## Tool: Product Description Generator - URL: https://boringtoolskit.com/product-description-generator/ - Category: Generators - Evidence: authored-methodology - Description: Generate a ready-to-use product description from your product, benefit, feature, and audience. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: The description is assembled from tone-specific templates that insert your product, benefit, feature, and audience, then appends a short benefit bullet list. - Assumptions: Generated output is a starting point, not final professional copy. | Nothing you type leaves your browser. | Results vary on each run because selection is random. - Sources: /methodology/ ## Tool: Profit Margin and Markup Calculator - URL: https://boringtoolskit.com/profit-margin-markup-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Calculate profit, profit margin, markup on cost, and the selling price needed for a target margin from your cost and price. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Margin = (price − cost) ÷ price × 100. Markup = (price − cost) ÷ cost × 100. The tool reports both from cost and price. - Assumptions: Cost is the per-unit total cost. | Price is before tax and discounts. | Overhead is handled separately. - Sources: https://en.wikipedia.org/wiki/Profit_margin | https://boringtoolskit.com/methodology/ ## Tool: Project Quote Calculator - URL: https://boringtoolskit.com/project-quote-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Project quote calculator: labor plus materials estimate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Property Area Calculator - URL: https://boringtoolskit.com/property-area-calculator/ - Category: Real Estate - Evidence: authored-methodology - Description: Convert property and land area between square feet, square meters, acres, hectares, and square yards. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Conversion between square feet, square meters, acres, hectares, and square yards using metric bases: 1 sq ft = 0.09290304 m², 1 sq yd = 0.83612736 m², 1 acre = 4,046.8564224 m², 1 hectare = 10,000 m². Value in target unit = value × base(unit) ÷ base(target). - Assumptions: Standard international definitions of the units are used. | Values are exact area measures, not rounded land measures. | No shape or survey information is required for a unit conversion. - Sources: https://www.nist.gov/pml/owm/metric-si/si-units-area | https://boringtoolskit.com/methodology/ ## Tool: Property Management Fee Calculator - URL: https://boringtoolskit.com/property-management-fee-calculator/ - Category: Real Estate - Evidence: catalogue - Description: Property management fee calculator: monthly and annual management fees plus a lease placement fee. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Property Tax Calculator - URL: https://boringtoolskit.com/property-tax-calculator/ - Category: Real Estate - Evidence: authored-methodology - Description: Estimate annual property tax from assessed value, tax rate, and exemptions for budgeting. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Property tax = (assessed value − exemptions − deductions) × tax rate ÷ 100, computed annually and divided by 12 for the monthly amount. - Assumptions: Assessed value and rate are entered by the user. | Exemptions/deductions reduce the taxable value. | The estimate is annual tax, divided by 12 for monthly. - Sources: https://www.investopedia.com/terms/p/property-tax.asp | https://boringtoolskit.com/methodology/ ## Tool: Proportion Solver - URL: https://boringtoolskit.com/proportion-solver/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Proportion solver: solve a/b = c/d for the unknown. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: If a/b = c/d, then d = (b × c) / a. - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Prorated Rent Calculator - URL: https://boringtoolskit.com/prorated-rent-calculator/ - Category: Real Estate - Evidence: catalogue - Description: Prorated rent calculator: how much rent to charge for a partial month move-in or move-out. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Protein Molecular Weight Calculator - URL: https://boringtoolskit.com/protein-molecular-weight-calculator/ - Category: Biology - Evidence: catalogue - Description: Protein molecular weight calculator: approximate mass from amino acid chain length. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Protein Shake Calculator - URL: https://boringtoolskit.com/protein-shake-calculator/ - Category: Health - Evidence: catalogue - Description: Protein shake calculator: protein per shake from scoops. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: PTO Accrual Calculator - URL: https://boringtoolskit.com/pto-accrual-calculator/ - Category: Time & Work - Evidence: catalogue - Description: PTO accrual calculator: vacation hours per year from a pay-period rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pulse Pressure Calculator - URL: https://boringtoolskit.com/pulse-pressure-calculator/ - Category: Health - Evidence: catalogue - Description: Pulse pressure calculator: the gap between systolic and diastolic. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Punnett Square Calculator - URL: https://boringtoolskit.com/punnett-square-calculator/ - Category: Biology - Evidence: catalogue - Description: Punnett square calculator: monohybrid cross offspring genotype and phenotype probabilities. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Puppy Adult Weight Calculator - URL: https://boringtoolskit.com/puppy-adult-weight-calculator/ - Category: Pets - Evidence: catalogue - Description: Puppy adult weight calculator: predicted adult weight from current age and weight. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Puppy Age Calculator - URL: https://boringtoolskit.com/puppy-age-calculator/ - Category: Pets - Evidence: catalogue - Description: Dog age calculator: dog years to human years (AAHA method). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Puppy Breed Size Calculator - URL: https://boringtoolskit.com/puppy-breed-size-calculator/ - Category: Pets - Evidence: catalogue - Description: Puppy breed size calculator: adult weight by breed category. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Push Up Test Calculator - URL: https://boringtoolskit.com/push-up-test-calculator/ - Category: Sports - Evidence: catalogue - Description: Push up test calculator: fitness rating by age and reps. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Pythagorean Theorem Calculator - URL: https://boringtoolskit.com/pythagorean-theorem-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Find the missing side of a right triangle using a² + b² = c². - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: a² + b² = c², where c is the hypotenuse. Solving for the hypotenuse: c = √(a² + b²). Solving for a leg: a = √(c² − b²) or b = √(c² − a²). - Assumptions: The triangle is right-angled. | All side lengths are in the same units. | The known leg is shorter than the hypotenuse when solving for a leg. - Sources: https://www.mathsisfun.com/pythagoras.html | https://boringtoolskit.com/methodology/ ## Tool: QR Code Generator - URL: https://boringtoolskit.com/qr-generator/ - Category: Generators - Evidence: authored-methodology - Description: Generate a QR code and download a PNG. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: A QR code encodes data (text or URL) into a grid of black and white modules. Error correction (L/M/Q/H) and version (size) are chosen by the generator; the code encodes the payload plus redundancy so scanners can read it even when partially damaged. - Assumptions: The payload is text or a URL. | The generated code follows standard QR encoding. | The scanner is a standard phone camera app. - Sources: https://en.wikipedia.org/wiki/QR_code | https://boringtoolskit.com/methodology/ ## Tool: Quadratic Formula Calculator - URL: https://boringtoolskit.com/quadratic-formula-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Solve a quadratic equation ax² + bx + c = 0 and see the roots. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: For ax² + bx + c = 0, roots = (−b ± √(b² − 4ac)) ÷ 2a. The discriminant D = b² − 4ac decides the roots: D > 0 gives two real roots, D = 0 a double root, D < 0 complex roots. Sum of roots = −b/a, product = c/a. - Assumptions: The equation is in standard form ax² + bx + c = 0. | a is non-zero. | Coefficients are real numbers. - Sources: https://www.mathsisfun.com/algebra/quadratic-equation.html | https://boringtoolskit.com/methodology/ ## Tool: Quarter Mile Time Calculator - URL: https://boringtoolskit.com/quarter-mile-time-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Quarter-mile time calculator: estimated ET and trap speed from horsepower and weight. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Quarterback Rating Calculator - URL: https://boringtoolskit.com/quarterback-rating-calculator/ - Category: Sports - Evidence: catalogue - Description: Quarterback rating calculator: NFL passer rating from attempts, completions, yards, touchdowns, and interceptions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Quartile Calculator - URL: https://boringtoolskit.com/quartile-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the first (Q1), second (median/Q2), and third (Q3) quartiles plus the interquartile range (IQR) of a data set. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Quartiles split the sorted data into four equal parts: Q1 is the median of the lower half, Q2 the median of the whole set, Q3 the median of the upper half. IQR = Q3 − Q1. - Assumptions: Quartiles need at least two values. | The method splits the data at the median and takes the median of each half. | Outliers can be flagged relative to the IQR, but the tool does not predict them. - Sources: https://www.itl.nist.gov/div898/handbook/ | https://boringtoolskit.com/methodology/ ## Tool: Quote / Estimate Generator - URL: https://boringtoolskit.com/quote-estimate-generator/ - Category: Generators - Evidence: authored-methodology - Description: Create a simple service quote or estimate with line items, taxes, deposits, payment terms, and a copyable client summary. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Line totals = quantity × unit price; subtotal = Σ lines; tax = subtotal × tax rate; total = subtotal + tax. The tool renders a client-ready quote from your line items. - Assumptions: Line items reflect the agreed scope. | The tax rate is a flat percentage. | Validity and payment terms are added by the user. - Sources: https://en.wikipedia.org/wiki/Invoice | https://boringtoolskit.com/methodology/ ## Tool: Raffle Odds Calculator - URL: https://boringtoolskit.com/raffle-odds-calculator/ - Category: Gaming - Evidence: catalogue - Description: Raffle odds calculator: win probability from tickets you hold vs total sold. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Rain Barrel Calculator - URL: https://boringtoolskit.com/rain-barrel-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Rain barrel calculator: gallons collected from roof runoff. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Raise Percentage Calculator - URL: https://boringtoolskit.com/raise-percentage-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Raise percentage calculator: new salary after a percent raise. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Raised Bed Soil Calculator - URL: https://boringtoolskit.com/raised-bed-soil-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Raised bed soil calculator: soil volume for a garden bed. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Random Name Picker - URL: https://boringtoolskit.com/random-name-picker/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Draw one name from a list of names you enter, using unbiased local browser randomness. Add names one per line, then pick. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Draws one (or more) names from a user-entered list using unbiased local browser randomness (Web Crypto). - Assumptions: Each line is one entry. | All entries are equal. | The draw is casual, not certified. - Sources: https://en.wikipedia.org/wiki/Randomness | https://boringtoolskit.com/methodology/ ## Tool: Random Number Generator - URL: https://boringtoolskit.com/random-number-generator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Generate one or up to 100 random integers from a custom range using unbiased local browser randomness. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Generates random integers in a chosen range, optionally unique and sorted, using a uniform random source. - Assumptions: The range is valid (min ≤ max). | Unique mode is possible for the range. | The random source is adequate for the use. - Sources: https://en.wikipedia.org/wiki/Random_number_generation | https://boringtoolskit.com/methodology/ ## Tool: Random Quote Generator - URL: https://boringtoolskit.com/random-quote-generator/ - Category: Generators - Evidence: authored-methodology - Description: Get random motivational and wisdom quotes by topic, instantly and without an account. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Quotes are drawn from curated topic pools and shuffled. Select a topic or leave it on Random to mix categories. - Assumptions: Generated output is a starting point, not final professional copy. | Nothing you type leaves your browser. | Results vary on each run because selection is random. - Sources: /methodology/ ## Tool: Random Team Splitter - URL: https://boringtoolskit.com/random-team-splitter/ - Category: Everyday Calculators - Evidence: catalogue - Description: Split any list of names into balanced random teams instantly. Choose team count or members per team — runs entirely in your browser. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: RC Time Constant Calculator - URL: https://boringtoolskit.com/rc-time-constant-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: RC time constant calculator: charge/discharge time constant and charge percentage. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Reaction Rate Calculator - URL: https://boringtoolskit.com/reaction-rate-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Calculate reaction rate from concentration change over time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Rate = k × [A]^x × [B]^y, using the rate constant k and the reaction order for each concentration. - Assumptions: The rate constant and at least one concentration and its order are required. | Concentration must be non-negative; [B] and its order are optional. | The rate law is a constant-temperature empirical model. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Readability Calculator - URL: https://boringtoolskit.com/readability/ - Category: Text & Developer Tools - Evidence: authored-methodology - Description: Score text readability and grade level. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Flesch Reading Ease = 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words). Score 90+ = very easy (children's text); 60–70 = plain English; below 30 = very difficult. - Assumptions: English-language text with standard syllable patterns. | The syllable-count heuristic is reasonable. | The score is a readability guide, not a quality metric. - Sources: https://en.wikipedia.org/wiki/Flesch%E2%80%93Kincaid_readability_tests | https://boringtoolskit.com/methodology/ ## Tool: Reading Speed Calculator - URL: https://boringtoolskit.com/reading-speed-calculator/ - Category: School & Education - Evidence: catalogue - Description: Reading speed calculator: words per minute and book reading time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Reading Time Calculator - URL: https://boringtoolskit.com/reading-time-calculator/ - Category: School & Education - Evidence: catalogue - Description: Reading time calculator: how long a text takes to read at your words-per-minute pace. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Receipt Generator - URL: https://boringtoolskit.com/receipt-generator/ - Category: Generators - Evidence: authored-methodology - Description: Create a simple payment receipt with payer, seller, items, tax, payment method, and a copyable receipt summary. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Line totals = quantity × unit price; subtotal = Σ lines; tax = subtotal × tax rate; total = subtotal + tax. The tool renders a printable receipt with seller, buyer, and item lines. - Assumptions: The user enters accurate transaction details. | Line items are entered as description, qty, price. | The tax rate is a flat percentage of the subtotal. - Sources: https://en.wikipedia.org/wiki/Receipt | https://boringtoolskit.com/methodology/ ## Tool: Recipe Divider Calculator - URL: https://boringtoolskit.com/recipe-divider-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Recipe divider calculator: split a recipe into fractions (half, third, quarter) with each ingredient scaled. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Regex Tester - URL: https://boringtoolskit.com/regex-tester/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Test a regular expression pattern against a string, see highlighted matches and a live match count, all in your browser. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Tests a regular expression pattern against sample text, showing matches, groups, and non-matches in real time. - Assumptions: JavaScript regex syntax applies. | The sample text represents real input. | Flags are applied as the user expects. - Sources: https://en.wikipedia.org/wiki/Regular_expression | https://boringtoolskit.com/methodology/ ## Tool: Remainder Calculator - URL: https://boringtoolskit.com/remainder-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Remainder calculator: quotient and remainder of a division. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Renovation Calculator - URL: https://boringtoolskit.com/renovation-calculator/ - Category: Real Estate - Evidence: authored-methodology - Description: Estimate renovation return on investment by comparing project cost, value added, and resale assumptions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Value recouped = value added ÷ project cost × 100. Renovation ROI = (value added − project cost) ÷ project cost × 100. Estimated new home value = current home value + value added. - Assumptions: Value added is entered by the user (from comps or agent guidance). | Recouped value is the resale lift, not the total benefit of the project. | The home's other characteristics stay constant. - Sources: https://www.nar.realtor/research-and-statistics/research-reports/remodeling-impact | https://boringtoolskit.com/methodology/ ## Tool: Rent Affordability Calculator - URL: https://boringtoolskit.com/rent-affordability-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate affordable rent using your income, chosen cap, debt, and savings. Your suggested maximum is the lower of the income cap or cash available. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Gross monthly income = annual income ÷ 12. Income-rule cap = gross × target % (usually 30%). Cash-based cap = gross − monthly debts − savings. Suggested rent = the lower of the two caps. - Assumptions: The 30% gross-income guideline applies. | Debts and savings are entered monthly. | Utilities and insurance are separate. - Sources: https://en.wikipedia.org/wiki/Renting | https://boringtoolskit.com/methodology/ ## Tool: Rent Split Calculator - URL: https://boringtoolskit.com/rent-split-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Rent split calculator: divide rent fairly by each roommate's income. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Rent-to-Value Calculator - URL: https://boringtoolskit.com/rent-to-value-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate the rent-to-value ratio and the 1% rule. Enter property value and monthly rent to screen a rental fast. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Rent-to-value = annual rent ÷ property value × 100. It's the inverse framing of the price-to-rent ratio — the annual rent as a percentage of the property's price. - Assumptions: Annual rent is monthly rent × 12. | Rent-to-value uses gross rent, not net operating income. | It's a comparison metric, not a profit figure. - Sources: https://www.investopedia.com/terms/p/price-to-rent-ratio.asp | https://boringtoolskit.com/methodology/ ## Tool: Rent vs. Buy Calculator - URL: https://boringtoolskit.com/rent-vs-buy-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Compare modeled buyer equity with a renter investment portfolio using explicit monthly cash flows. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Compares total costs over a horizon: buying (down payment, mortgage payments, taxes, insurance, maintenance, minus equity and appreciation) vs renting (rent, renter's insurance, minus investment returns on the saved down payment). - Assumptions: The entered rates and growth assumptions are reasonable estimates. | The buyer stays for the full horizon. | Maintenance and taxes are approximated by the entered percentages. - Sources: https://en.wikipedia.org/wiki/Renting | https://boringtoolskit.com/methodology/ ## Tool: Rental Car Cost Calculator - URL: https://boringtoolskit.com/rental-car-cost-calculator/ - Category: Travel - Evidence: catalogue - Description: Rental car cost calculator: full rental cost including insurance, gas, and daily rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Rental Cash Flow Calculator - URL: https://boringtoolskit.com/rental-cash-flow-calculator/ - Category: Real Estate - Evidence: catalogue - Description: Rental cash flow calculator: monthly net cash flow after all costs. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Rental Property ROI Calculator - URL: https://boringtoolskit.com/rental-property-roi-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate total return on a rental property. Combine cash flow, loan paydown, and appreciation over your holding period. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Rental property ROI = (total return ÷ total cash invested) × 100, where total return = cumulative cash flow + appreciation gain + principal paydown, and total cash invested is your down payment (plus any equity put in). - Assumptions: Annual cash flow is pre-tax and held constant across years. | Appreciation is applied to property value over the holding period. | ROI is divided by the down payment (cash invested). - Sources: https://www.investopedia.com/terms/c/cash-on-cash-return.asp | https://boringtoolskit.com/methodology/ ## Tool: Rental Yield Calculator - URL: https://boringtoolskit.com/rental-yield-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate gross rental yield. Enter property price and annual rent for the quick first-pass screen on a rental. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Gross rental yield = annual rent ÷ property value × 100. Monthly rent × 12 gives the annual rent, divided by the property price to get the yield as a percentage. - Assumptions: Gross yield uses annual rent before any operating expenses. | Property value is the purchase price or current market value. | This is a gross metric — it does not include financing or costs. - Sources: https://www.investopedia.com/terms/c/capitalization-rate.asp | https://boringtoolskit.com/methodology/ ## Tool: Resistor Color Code Calculator - URL: https://boringtoolskit.com/resistor-calculator/ - Category: Physics - Evidence: catalogue - Description: Resistor color code calculator: 4-band resistor value and tolerance from color bands. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Retainer Calculator - URL: https://boringtoolskit.com/retainer-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Retainer calculator: monthly retainer from hourly rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Retirement Planning Calculator - URL: https://boringtoolskit.com/retirement-planning-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Project retirement savings, inflation-adjusted value, contributions, and a planning withdrawal estimate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Each month: balance = prior balance × (1 + annual return ÷ 12) + contribution; real value discounts the result by inflation. - Assumptions: Returns, inflation, and contributions remain constant. | Contributions are made at month-end and taxes/fees are excluded. | The withdrawal rate is a planning input, not a guarantee that savings will last. - Sources: https://www.investor.gov/financial-tools-calculators/calculators/compound-interest-calculator | https://www.dol.gov/agencies/ebsa/about-ebsa/our-activities/resource-center/publications/taking-the-mystery-out-of-retirement-planning ## Tool: Retirement Withdrawal Calculator - URL: https://boringtoolskit.com/retirement-withdrawal-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Retirement withdrawal calculator: safe annual and monthly withdrawals from a portfolio using the 4% rule. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Return on Investment Calculator - URL: https://boringtoolskit.com/return-on-investment-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Return on investment calculator: ROI from cost and gain. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: RGB to Hex Converter - URL: https://boringtoolskit.com/rgb-to-hex-calculator/ - Category: Colors & Design - Evidence: catalogue - Description: RGB to hex converter: convert red, green, blue values (0–255) to a #RRGGBB hex color instantly. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Rice Water Ratio Calculator - URL: https://boringtoolskit.com/rice-water-ratio-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Rice water ratio calculator: water per cup of rice by type. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Ring Size Calculator - URL: https://boringtoolskit.com/ring-size-calculator/ - Category: Converters - Evidence: catalogue - Description: Ring size calculator: US ring size from finger circumference. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: RMD Calculator - URL: https://boringtoolskit.com/rmd-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate the Required Minimum Distribution from a retirement account at age 73+. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: RMD = account balance ÷ IRS life-expectancy factor. The tool uses the Uniform Lifetime Table factors: 26.5 at age 73, 24.6 at 75, 22.0 at 78, 20.2 at 80, 16.8 at 85, and 12.9 at 90 (falls back to 24.6 for other ages). - Assumptions: The IRS Uniform Lifetime Table factor for the entered age is used. | The balance is the prior year-end account value. | No spousal or inherited-account table applies. - Sources: https://www.investopedia.com/terms/r/requiredminimumdistribution.asp | https://boringtoolskit.com/methodology/ ## Tool: Road Trip Cost Calculator - URL: https://boringtoolskit.com/road-trip-cost-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Road trip cost calculator: fuel, hotels, and food for a trip. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Road Trip Time Calculator - URL: https://boringtoolskit.com/road-trip-time-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Road trip time calculator: drive time and arrival from distance, speed, and stops. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Roman Numeral Converter - URL: https://boringtoolskit.com/roman-numeral-converter/ - Category: Converters - Evidence: authored-methodology - Description: Convert between decimal numbers and Roman numerals (1–4999) in either direction with validation. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Decimal to Roman: repeatedly subtract the largest available symbol (M, CM, D, CD, C, XC, L, XL, X, IX, V, IV, I). Roman to decimal: add each symbol, subtracting when a smaller symbol precedes a larger one. - Assumptions: Standard (non-overline) Roman numerals are used, covering 1–4999. | Subtractive notation (IV, IX, XL, XC, CD, CM) is recognized. - Sources: /methodology/ ## Tool: Roof Pitch Calculator - URL: https://boringtoolskit.com/roof-pitch-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Roof pitch calculator: roof angle and slope factor from rise per foot of run. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Roofing Calculator - URL: https://boringtoolskit.com/roofing-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate roof area, roofing squares, and shingle bundles from footprint and pitch. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Pitch factor = √(1 + (rise ÷ 12)²). Roof area = length × width × pitch factor. Area with waste = roof area × (1 + waste%). Roofing squares = total ÷ 100. Bundles ≈ squares × 3 (three bundles per square). - Assumptions: A simple sloped (gable-style) roof geometry. | Rise is inches of vertical per 12 inches of horizontal run. | 3 bundles of shingles per roofing square. - Sources: https://en.wikipedia.org/wiki/Roofing | https://boringtoolskit.com/methodology/ ## Tool: Root Calculator - URL: https://boringtoolskit.com/root-calculator/ - Category: School & Education - Evidence: catalogue - Description: Root calculator: the nth root of any number, including cube and fourth roots. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Roth IRA Calculator - URL: https://boringtoolskit.com/roth-ira-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate the future value of a Roth IRA with annual contributions and tax-free growth. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Future value = current balance × (1 + rate)^years + annual contribution × [((1 + rate)^years − 1) ÷ rate]. It compounds your existing balance and each year's contribution at the assumed annual return. - Assumptions: Contributions are made at the end of each year. | A single constant annual return is assumed. | The estimate excludes fees and income/contribution limits. - Sources: https://www.investopedia.com/terms/r/roth-ira.asp | https://boringtoolskit.com/methodology/ ## Tool: Round Up Down Calculator - URL: https://boringtoolskit.com/round-up-down-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Round up/down calculator: nearest multiple in both directions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Round to the chosen place: look at the digit to its right; 0–4 rounds down, 5–9 rounds up (round half up). - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Rounding Numbers Calculator - URL: https://boringtoolskit.com/rounding-numbers-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Round any number to the nearest ten, one, tenth, hundredth, or thousandth , with every place shown at once. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Rounds a number to a chosen number of decimal places: 3.14159 → 3.14 at 2 places. The tool also shows the nearest integer and significant-value forms. - Assumptions: Standard half-up rounding applies. | Decimal places are non-negative. | The result is for display or reporting. - Sources: https://en.wikipedia.org/wiki/Rounding | https://boringtoolskit.com/methodology/ ## Tool: Royalty Calculator - URL: https://boringtoolskit.com/royalty-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Royalty calculator: earnings from sales at a royalty rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Rug Size Calculator - URL: https://boringtoolskit.com/rug-size-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Rug size calculator: recommended rug for a room. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Rule of 72 Calculator - URL: https://boringtoolskit.com/rule-of-72-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Rule of 72 calculator: how many years to double your money at a given rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Salary to Hourly Converter - URL: https://boringtoolskit.com/salary-hourly-converter/ - Category: Time & Work - Evidence: authored-methodology - Description: Convert annual salary to hourly, weekly, biweekly, and monthly equivalents. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Hourly = annual salary ÷ (weeks worked × hours per week). Weekly = annual ÷ weeks. Biweekly = annual ÷ 26. Monthly = annual ÷ 12. - Assumptions: The salary is pre-tax gross. | Weeks and hours reflect the real schedule. | No bonus or benefit value is included. - Sources: https://en.wikipedia.org/wiki/Salary | https://boringtoolskit.com/methodology/ ## Tool: Sales Commission Calculator - URL: https://boringtoolskit.com/sales-commission-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Sales commission calculator: earnings from a sale at a commission rate plus any base. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sales Tax by ZIP Code - URL: https://boringtoolskit.com/sales-tax-by-zip-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Sales tax by ZIP code: see the candidate states, base rate, and local ceiling for any US ZIP. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sales Tax Calculator - URL: https://boringtoolskit.com/sales-tax-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Sales tax calculator: state base rate and total on a purchase. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sales Tax and VAT Calculator - URL: https://boringtoolskit.com/sales-tax-vat-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Sales tax calculator that adds or removes tax or VAT using your editable rate. Get the net amount, tax amount, and gross total instantly. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Add tax: total = price × (1 + rate). Remove tax: pre-tax = total ÷ (1 + rate). The tool includes US state rates and EU/UK VAT references. - Assumptions: The entered rate is current for the jurisdiction. | One rate applies to the whole purchase. | No exemptions or category variations apply. - Sources: https://en.wikipedia.org/wiki/Sales_tax | https://boringtoolskit.com/methodology/ ## Tool: Audio File Size Calculator - URL: https://boringtoolskit.com/sample-rate-bit-depth-calculator/ - Category: Music & Audio - Evidence: catalogue - Description: Audio file size calculator: uncompressed size from duration, sample rate, bit depth, and channels. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sample Size Calculator - URL: https://boringtoolskit.com/sample-size-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Determine the sample size needed for a survey or study at a given confidence and margin. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Required sample size n₀ = z² × p(1 − p) ÷ e², where z is the critical value for the confidence level (1.645/1.96/2.576), p is the expected proportion, and e is the margin of error. With a finite population, n = n₀ ÷ (1 + (n₀ − 1) ÷ N). - Assumptions: Simple random sampling with independent observations. | The proportion p is close to the expected value. | Non-response and design effects are not included. - Sources: https://www.itl.nist.gov/div898/handbook/prc/section2/prc252.htm | https://boringtoolskit.com/methodology/ ## Tool: Savings Growth Calculator - URL: https://boringtoolskit.com/savings-calc/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Savings calculator for monthly compound growth. Enter an amount, annual rate, and years to estimate your future savings value. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Growth = principal × (1 + rate ÷ n)^(n × years), where n is the compounding frequency. The tool projects the balance over time. - Assumptions: A constant APY over the period. | No withdrawals. | No additional contributions. - Sources: https://en.wikipedia.org/wiki/Compound_interest | https://boringtoolskit.com/methodology/ ## Tool: Savings Goal Calculator - URL: https://boringtoolskit.com/savings-goal-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate the monthly deposit needed to reach a savings goal with an editable APY and deadline. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Monthly rate = (1 + APY)^(1/12) − 1; required deposit = remaining future value ÷ annuity future-value factor. - Assumptions: APY stays constant through the deadline. | Deposits occur at the end of each month. | Taxes, fees, rate tiers, and withdrawal restrictions are excluded. - Sources: https://www.fdic.gov/resources/bankers/national-rates/ | https://www.investor.gov/financial-tools-calculators/calculators/compound-interest-calculator ## Tool: Scale Converter - URL: https://boringtoolskit.com/scale-converter/ - Category: Converters - Evidence: catalogue - Description: Scale converter: real-world size from map or blueprint scale. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Scale Finder Calculator - URL: https://boringtoolskit.com/scale-finder-calculator/ - Category: Music & Audio - Evidence: authored-methodology - Description: Find the notes in any major, minor, pentatonic, blues, or modal scale from a root. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Scale notes = root index + interval pattern (in semitones) mod 12, over the 12-note chromatic set. Supported patterns: major [0,2,4,5,7,9,11], minor [0,2,3,5,7,8,10], pentatonic major/minor, blues, dorian, mixolydian, lydian. - Assumptions: Root is a note name and scale is a supported pattern. | Intervals are in semitones from the root. | The output shows the notes in the selected pattern, not a chord or voicing. - Sources: https://boringtoolskit.com/methodology/ ## Tool: School Supply Budget Calculator - URL: https://boringtoolskit.com/school-supply-budget-calculator/ - Category: School & Education - Evidence: authored-methodology - Description: Estimate a back-to-school supply budget by grade level and number of children, including clothing, backpack extras, and estimated tax. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Totals the estimated cost of school supplies and compares it against a budget, showing the surplus or shortfall. - Assumptions: Prices are entered accurately. | Sales tax is added by the user. | The budget is the user's chosen cap. - Sources: https://en.wikipedia.org/wiki/Stationery | https://boringtoolskit.com/methodology/ ## Tool: Scientific Notation Converter - URL: https://boringtoolskit.com/scientific-notation-converter/ - Category: Converters - Evidence: authored-methodology - Description: Convert any number to and from scientific and engineering notation with significant-figure control. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Scientific notation writes the number as a mantissa between 1 and 10 times a power of ten: value = mantissa × 10^exponent. The exponent is floor(log10(|value|)). Engineering notation restricts the exponent to a multiple of 3. - Assumptions: The value is written exactly to the requested significant figures. | Exponent is derived from the absolute value; the sign is shown separately. | Very large or small magnitudes are limited by JavaScript’s number range. - Sources: /methodology/ ## Tool: Screen Size Calculator - URL: https://boringtoolskit.com/screen-size-calculator/ - Category: Converters - Evidence: catalogue - Description: Screen size calculator: width and height from diagonal and aspect. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: 1099 Income Tax Calculator - URL: https://boringtoolskit.com/self-employment-tax/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Estimate federal self-employment tax and a quarterly planning amount for 1099 income. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Net earnings = profit × 92.35%. Self-employment tax = net × 15.3% (12.4% Social Security + 2.9% Medicare, with the Social Security wage cap). The tool also estimates federal income tax. - Assumptions: US federal tax rules apply. | The standard deduction is used. | No state or city tax is modeled. - Sources: https://en.wikipedia.org/wiki/Self-employment_tax | https://boringtoolskit.com/methodology/ ## Tool: Semester GPA Calculator - URL: https://boringtoolskit.com/semester-gpa-calculator/ - Category: School & Education - Evidence: catalogue - Description: Semester GPA calculator: grade point average from course credits and grade points. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Semicircle Calculator - URL: https://boringtoolskit.com/semicircle-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Semicircle calculator: area and arc length. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Area = (π × r²)/2; perimeter = π × r + 2r (arc plus the straight diameter). - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Sensitivity Specificity Calculator - URL: https://boringtoolskit.com/sensitivity-specificity-calculator/ - Category: Health - Evidence: catalogue - Description: Sensitivity and specificity calculator: diagnostic test performance. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Septic Tank Size Calculator - URL: https://boringtoolskit.com/septic-tank-size/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate a septic tank size in gallons from the number of bedrooms and daily usage assumptions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Daily flow = number of bedrooms (or occupants) × gallons per person per day. Sized tank = ceil(daily flow × safety factor). Common tank sizes: 750, 1,000, 1,250, 1,500 gallons. - Assumptions: Daily flow is estimated from the number of bedrooms or occupants. | The safety factor provides a buffer for retention and peak usage. | Local code requirements govern the final size. - Sources: https://en.wikipedia.org/wiki/Septic_tank | https://boringtoolskit.com/methodology/ ## Tool: Serial Dilution Calculator - URL: https://boringtoolskit.com/serial-dilution-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Calculate serial dilution concentrations and cumulative dilution factors. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Concentration at step i = stock × (1 ÷ dilution factor)^i. - Assumptions: Stock concentration, dilution factor (>1), and step count (1–20) are entered. | Each step multiplies the previous concentration by 1 ÷ factor. | The calculation assumes equal transfer and mixing volumes at each step. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Series Sum Calculator - URL: https://boringtoolskit.com/series-sum-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Arithmetic series sum calculator: a1 + (a1+d) + ... - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Severance Pay Calculator - URL: https://boringtoolskit.com/severance-pay-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Severance pay calculator: payout from weeks and salary. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Shift Differential Calculator - URL: https://boringtoolskit.com/shift-differential-calculator/ - Category: Time & Work - Evidence: authored-methodology - Description: Estimate base pay, shift premium, overtime, and total gross shift pay. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Shift premium = base pay × differential %. Total = (regular hours × rate × (1 + differential)) + overtime hours × rate × overtime multiplier. - Assumptions: The differential applies to regular hours. | Overtime uses the base rate × multiplier. | The premium reflects the employer's policy. - Sources: https://en.wikipedia.org/wiki/Shift_work | https://boringtoolskit.com/methodology/ ## Tool: Shiplap Calculator - URL: https://boringtoolskit.com/shiplap-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Shiplap calculator: boards needed for a wall with waste. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Shoe Size Conversion - URL: https://boringtoolskit.com/shoe-size-conversion/ - Category: Converters - Evidence: catalogue - Description: Shoe size conversion: US men's and women's to UK, EU, and centimeters (approximate). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Shooting Percentage Calculator - URL: https://boringtoolskit.com/shooting-percentage-calculator/ - Category: Sports - Evidence: catalogue - Description: Shooting percentage calculator: field-goal percentage from makes and attempts. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Shopify Fee Calculator - URL: https://boringtoolskit.com/shopify-fee-calculator/ - Category: Seller & Business - Evidence: catalogue - Description: Shopify fee calculator: monthly plan plus transaction fees on your sales volume. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Shopify Profit Calculator - URL: https://boringtoolskit.com/shopify-profit-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Free Shopify profit calculator: estimate payment processing, product, shipping, and ad costs plus net order profit and margin , with editable 2026 assumptions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Profit = revenue − payment fees (2.9% + $0.30 typical) − product costs − shipping − other costs. - Assumptions: The payment rate reflects the store's plan. | Product and shipping costs are entered. | Subscription and apps are separate fixed costs. - Sources: https://en.wikipedia.org/wiki/Shopify | https://boringtoolskit.com/methodology/ ## Tool: Shutter Speed Stops Calculator - URL: https://boringtoolskit.com/shutter-speed-stops-calculator/ - Category: Photo & Video - Evidence: catalogue - Description: Shutter speed stops calculator: find how many exposure stops (EV) differ between two shutter speeds. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Siding Calculator - URL: https://boringtoolskit.com/siding-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Siding calculator: squares of siding from wall area and waste allowance. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Significant Figures Calculator - URL: https://boringtoolskit.com/significant-figures-calculator/ - Category: Chemistry - Evidence: catalogue - Description: Significant figures calculator: round a number to a given number of significant digits. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Simple Interest Calculator - URL: https://boringtoolskit.com/simple-interest-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate simple interest and total amount with interest using principal, annual rate, and time. Simple interest applies only to the original principal. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Interest = principal × rate × time (I = P×r×t). Total = principal + interest. Interest per year = principal × rate. - Assumptions: The rate is annual and time is in years. | Interest is not compounded. | No payments are made during the term. - Sources: https://en.wikipedia.org/wiki/Interest | https://boringtoolskit.com/methodology/ ## Tool: Sit Up Test Calculator - URL: https://boringtoolskit.com/sit-up-test-calculator/ - Category: Sports - Evidence: catalogue - Description: Sit up test calculator: abdominal endurance rating. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sitemap Validator - URL: https://boringtoolskit.com/sitemap-validate/ - Category: Converters - Evidence: authored-methodology - Description: Validate XML sitemap and robots basics. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Parses the sitemap XML, checks it's well-formed (no parser errors), verifies the root element, and lists every URL. Invalid XML and missing URL elements are flagged. - Assumptions: The sitemap uses standard sitemaps.org XML. | The user pastes the complete XML document. | Search-engine limits are checked separately. - Sources: https://en.wikipedia.org/wiki/Sitemaps | https://boringtoolskit.com/methodology/ ## Tool: Skewness Calculator - URL: https://boringtoolskit.com/skewness-calculator/ - Category: Statistics - Evidence: catalogue - Description: Skewness calculator: asymmetry of a sample distribution. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Ski Length Calculator - URL: https://boringtoolskit.com/ski-length-calculator/ - Category: Sports - Evidence: catalogue - Description: Ski length calculator: recommended ski length from height and style. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sleep Cycle Calculator - URL: https://boringtoolskit.com/sleep-calculator/ - Category: Health - Evidence: catalogue - Description: Sleep cycle calculator: best bedtime to wake refreshed in 90-minute cycles. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sleep Cycle Calculator - URL: https://boringtoolskit.com/sleep-cycle-calculator/ - Category: Health - Evidence: catalogue - Description: Sleep cycle calculator: find ideal bedtimes that end on a 90-minute sleep cycle for your wake time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sleep Debt Calculator - URL: https://boringtoolskit.com/sleep-debt-calculator/ - Category: Health - Evidence: catalogue - Description: Sleep debt calculator: accumulated lost sleep from target hours, actual hours, and days tracked. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sleep Length Calculator - URL: https://boringtoolskit.com/sleep-length-calculator/ - Category: Health - Evidence: catalogue - Description: Sleep length calculator: hours and minutes from sleep cycles, plus when to wake. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Slogan Generator - URL: https://boringtoolskit.com/slogan-generator/ - Category: Generators - Evidence: authored-methodology - Description: Generate brand slogan and tagline ideas from your business, benefit, and industry. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Slogans are built from pattern templates that swap in your business, key benefit, and industry. The templates are rotated and de-duplicated to return a fresh set each time. - Assumptions: Generated output is a starting point, not final professional copy. | Nothing you type leaves your browser. | Results vary on each run because selection is random. - Sources: /methodology/ ## Tool: Slope Calculator - URL: https://boringtoolskit.com/slope-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Slope calculator: degrees, percent grade, and ratio from rise and run. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Slope Intercept Calculator - URL: https://boringtoolskit.com/slope-intercept-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Slope intercept calculator: y = mx + b from two points. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Slug Generator - URL: https://boringtoolskit.com/slug-generator/ - Category: Text & Developer Tools - Evidence: catalogue - Description: Turn any headline or phrase into a clean, URL-friendly slug instantly in your browser. SEO-ready output with a one-click copy. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Smoker Time Calculator - URL: https://boringtoolskit.com/smoker-time-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Smoker time calculator: smoking time by cut at 225°F. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Soccer Speed Calculator - URL: https://boringtoolskit.com/soccer-speed-calculator/ - Category: Sports - Evidence: catalogue - Description: Soccer speed calculator: sprint speed from distance and time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Social Media Earnings Calculator - URL: https://boringtoolskit.com/social-media-earnings-calculator/ - Category: Social Media - Evidence: authored-methodology - Description: Estimate potential income from social platforms and sponsorship value. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Total earnings = monthly revenue × months. Annual equivalent = monthly revenue × 12. - Assumptions: Monthly revenue is a steady average across the period. | Earnings are gross before tax and platform deductions. | Revenue is not projected to grow or shrink across the months. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Social Media Engagement Rate Calculator - URL: https://boringtoolskit.com/social-media-engagement-rate-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate engagement rate from likes, comments, shares, and reach or followers, and compare against typical benchmarks. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Engagement rate = (likes + comments + shares) ÷ followers × 100, or ÷ reach × 100 when reach is the denominator. - Assumptions: Interactions are likes + comments + shares. | The denominator is followers or reach as chosen. | Rates are compared within the same platform. - Sources: https://en.wikipedia.org/wiki/Social_media | https://boringtoolskit.com/methodology/ ## Tool: Social Security Break Even Calculator - URL: https://boringtoolskit.com/social-security-break-even-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Social security break-even calculator: at what age claiming later pays off vs claiming at 62. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Social Security Tax Calculator - URL: https://boringtoolskit.com/social-security-tax-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Social Security tax calculator: how much of your benefit is taxable (50% or 85% rule). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sodium Calculator - URL: https://boringtoolskit.com/sodium-calculator/ - Category: Health - Evidence: catalogue - Description: Sodium calculator: mg sodium to salt grams and daily value. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Solar Panel Savings Calculator - URL: https://boringtoolskit.com/solar-panel-savings-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Solar panel savings calculator: annual savings and payback period from system size, cost, and utility rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sonotube Concrete Calculator - URL: https://boringtoolskit.com/sonotube-concrete-column/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate concrete for a round sonotube column in cubic feet, cubic yards, and 60/80 lb bags. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Radius r = (diameter ÷ 2) ÷ 12 (ft). Volume per tube = π × r² × height. Total = volume per tube × number of tubes. Cubic yards = total ÷ 27. Order = cubic yards × (1 + waste%). Bags: 60 lb ≈ 0.45 cu ft each; 80 lb ≈ 0.6 cu ft. - Assumptions: Tubes are uniform cylinders filled to the top. | Bags are 60 lb (0.45 cu ft) or 80 lb (0.6 cu ft). | Waste covers spillage and uneven tops. - Sources: https://www.quikrete.com/calculator/main.asp | https://boringtoolskit.com/methodology/ ## Tool: Soup Scale Calculator - URL: https://boringtoolskit.com/soup-scale-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Soup scale calculator: scale a soup or stock recipe from a base yield to a target yield. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sourdough Hydration Calculator - URL: https://boringtoolskit.com/sourdough-hydration-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Sourdough hydration calculator: dough hydration percentage. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sous Vide Time Calculator - URL: https://boringtoolskit.com/sous-vide-time-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Sous vide time calculator: cooking time by cut and thickness. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Speaking Time Calculator - URL: https://boringtoolskit.com/speaking-time-calculator/ - Category: School & Education - Evidence: catalogue - Description: Speaking time calculator: how long a script takes to say. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Speed Converter - URL: https://boringtoolskit.com/speed-converter/ - Category: Converters - Evidence: catalogue - Description: Speed converter: mph, km/h, m/s, ft/s, and knots. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Speed Distance Time Calculator - URL: https://boringtoolskit.com/speed-distance-time-calculator/ - Category: Physics - Evidence: catalogue - Description: Speed distance time calculator: solve for the missing value (speed, distance, or time). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sphere Volume Calculator - URL: https://boringtoolskit.com/sphere-volume-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Sphere volume calculator: volume and surface area from radius. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Volume = (4/3) × π × r³; surface area = 4 × π × r². - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Sprinkler Heads Calculator - URL: https://boringtoolskit.com/sprinkler-heads-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Sprinkler heads calculator: heads needed for a lawn area. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sprint Capacity Calculator - URL: https://boringtoolskit.com/sprint-capacity-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Sprint capacity calculator: team capacity in person-days and hours. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Square Fee Calculator - URL: https://boringtoolskit.com/square-fee-calculator/ - Category: Seller & Business - Evidence: catalogue - Description: Square fee calculator: the 2.6% + 10\u00a2 card-present fee and your net. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Square Feet to Linear Feet Calculator - URL: https://boringtoolskit.com/square-feet-to-linear-feet/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Convert square feet or square yards to linear material length using the required material width. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Linear feet = area ÷ material width (converted to feet). It converts a square-foot purchase into the linear length of a roll, board, or strip. - Assumptions: The material is a uniform strip of the entered width. | Area and width use convertible units. | Waste is added by the user (~10%). - Sources: https://en.wikipedia.org/wiki/Board_foot | https://boringtoolskit.com/methodology/ ## Tool: Square Footage Calculator - URL: https://boringtoolskit.com/square-footage-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Calculate square footage for rooms and projects with waste allowance, square-yard/meter/acre conversions, and optional material cost estimate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Area 1 = length1 × width1; Area 2 = length2 × width2; base total = area1 + area2. Total with waste = base × (1 + waste%). Conversions: sq yd = total ÷ 9, sq m = total × 0.09290304, acres = total ÷ 43,560. Estimated material cost = total × price per unit. - Assumptions: Up to two rectangular areas are entered. | Waste is a percentage of the base total. | Conversions use standard international definitions. - Sources: https://www.calculatorsoup.com/calculators/construction/square-footage-calculator.php | https://boringtoolskit.com/methodology/ ## Tool: Stair Calculator - URL: https://boringtoolskit.com/stair-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate stair riser count, actual riser height, treads, total run, and stringer length. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Risers = ceiling(total rise ÷ target riser); actual riser = total rise ÷ risers; treads = risers − 1; stringer slope = √(rise² + run²). - Assumptions: The stair is a straight flight with equal risers. | The target is used to choose a count; local code controls maximum riser and minimum tread. | Structural sizing, nosing, landings, headroom, guards, and handrails are excluded. - Sources: https://www.iccsafe.org/products-and-services/i-codes/2024-i-codes/irc/ | https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.1052 ## Tool: Staircase Calculator - URL: https://boringtoolskit.com/staircase-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Staircase calculator: number of treads and total run from floor height and chosen rise. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Standard Deviation Calculator - URL: https://boringtoolskit.com/standard-deviation-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the sample or population standard deviation, variance, mean, and margin of error for any set of numbers. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Standard deviation = √(Σ(xᵢ − mean)² ÷ n) for a population, or ÷ (n − 1) for a sample. It measures how spread out values are around the mean. - Assumptions: At least two numbers are provided. | The mode (population/sample) matches the context. | Values are numeric. - Sources: https://en.wikipedia.org/wiki/Standard_deviation | https://boringtoolskit.com/methodology/ ## Tool: Standard Error Calculator - URL: https://boringtoolskit.com/standard-error-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the standard error of the mean (SEM). Enter sample standard deviation and size to measure how precise the sample mean is. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Standard error of the mean (SEM) = standard deviation ÷ √sample size. 95% margin = ±1.96 × SEM. - Assumptions: Sample size must be ≥1 and standard deviation ≥0. | The 95% margin assumes an approximately normal sampling distribution. | SEM measures how far the sample mean is likely to fall from the true mean. - Sources: https://www.itl.nist.gov/div898/handbook/ | https://boringtoolskit.com/methodology/ ## Tool: Standing Desk Calculator - URL: https://boringtoolskit.com/standing-desk-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Standing desk calculator: desk, chair, and monitor heights from your height. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Star Magnitude Calculator - URL: https://boringtoolskit.com/star-magnitude-calculator/ - Category: Astronomy - Evidence: catalogue - Description: Star magnitude calculator: brightness ratio between two apparent magnitudes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Statistics Calculator - URL: https://boringtoolskit.com/statistics-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Compute descriptive statistics for a sample or population: mean, median, mode, range, sum, count, standard deviation, variance, and geometric mean. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Mean = Σx ÷ n. Sample variance s² = Σ(x − mean)² ÷ (n − 1); population σ² = Σ(x − mean)² ÷ n. Standard deviation = √variance. Median is the middle value (or mean of the two middle values for even n). Mode is the most frequent value. - Assumptions: The tool splits the input on commas, whitespace, or semicolons and treats each number as one observation. | Sample mode uses n−1 for the denominator, population uses n. | Geometric mean is shown only for data sets of positive values. - Sources: https://www.itl.nist.gov/div898/handbook/ | https://boringtoolskit.com/methodology/ ## Tool: Steak Doneness Calculator - URL: https://boringtoolskit.com/steak-doneness-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Steak doneness calculator: internal temperature guide. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Stellar Temperature Calculator - URL: https://boringtoolskit.com/stellar-temperature-calculator/ - Category: Astronomy - Evidence: catalogue - Description: Stellar temperature calculator: blackbody temperature from peak wavelength (Wien's law). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Steps to Miles Calculator - URL: https://boringtoolskit.com/steps-to-miles-calculator/ - Category: Health - Evidence: catalogue - Description: Steps to miles calculator: distance walked and calories burned from step count. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Average Share Cost Calculator - URL: https://boringtoolskit.com/stock-average-cost-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate weighted average share cost, total shares, cost basis, and unrealized gain. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Average cost per share = (shares₁ × price₁ + shares₂ × price₂ + …) ÷ total shares. It tracks the blended basis after multiple buys. - Assumptions: No splits, dividends, or fees are modeled. | All purchases are of the same stock. | Simple average-cost basis applies. - Sources: https://en.wikipedia.org/wiki/Average_cost_method | https://boringtoolskit.com/methodology/ ## Tool: Share Profit Calculator - URL: https://boringtoolskit.com/stock-calc/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Calculate stock profit, ROI, and per-share returns. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Profit = (sell price − buy price) × shares − buy fees − sell fees. Return on investment = profit ÷ (buy price × shares + buy fee) × 100. Breakeven price = buy price + fees ÷ shares. - Assumptions: No dividends or distributions during the holding period. | Fees are fixed per trade as entered. | Simple, non-leveraged position. - Sources: https://en.wikipedia.org/wiki/Capital_gain | https://boringtoolskit.com/methodology/ ## Tool: Stock Return Calculator - URL: https://boringtoolskit.com/stock-return-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Stock return calculator: total return including dividends. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Stoichiometry Calculator - URL: https://boringtoolskit.com/stoichiometry-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Calculate reactant and product quantities from balanced equation ratios. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Moles of reactant = mass ÷ molar mass. Moles of product = reactant moles × (product coefficient ÷ reactant coefficient). Product mass = product moles × product molar mass. - Assumptions: Reactant mass, both molar masses, and both coefficients are required. | Molar masses must be positive and coefficients non-zero. | The calculation uses the balanced-equation mole ratio. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Stone to Pounds Converter - URL: https://boringtoolskit.com/stone-pounds-converter/ - Category: Converters - Evidence: catalogue - Description: Stone to pounds converter: stone, pounds, kg. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Stopping Distance Calculator - URL: https://boringtoolskit.com/stopping-distance-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Stopping distance calculator: reaction plus braking distance by speed. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Stopwatch - URL: https://boringtoolskit.com/stopwatch/ - Category: Time & Work - Evidence: authored-methodology - Description: Time events with lap tracking — start, stop, and record laps to hundredths of a second. Free, private, runs locally in your browser. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Elapsed time = current time − start time, measured in milliseconds and displayed as minutes:seconds.hundredths. Lap times record the interval between lap presses. - Assumptions: The browser tab remains active. | Millisecond-level timing from the system clock is sufficient. | Laps are recorded in sequence. - Sources: https://en.wikipedia.org/wiki/Stopwatch | https://boringtoolskit.com/methodology/ ## Tool: Story Points to Hours Calculator - URL: https://boringtoolskit.com/story-points-to-hours-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Story points to hours calculator: agile estimation conversion. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Stride Length Calculator - URL: https://boringtoolskit.com/stride-length-calculator/ - Category: Health - Evidence: catalogue - Description: Stride length calculator: stride from height for walking or running. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Stripe Fee Calculator - URL: https://boringtoolskit.com/stripe-fee-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate estimated Stripe fees, net proceeds, or the amount to charge for a target net. Starts with an editable 2.9% + $0.30 planning preset. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Fee = amount × 2.9% + $0.30 (US standard online rate). Net = amount − fee. Rates vary by country, card type, and volume. - Assumptions: The standard US online rate applies. | No currency conversion or international card fees. | The charge is a standard card payment. - Sources: https://en.wikipedia.org/wiki/Stripe,_Inc. | https://boringtoolskit.com/methodology/ ## Tool: Student Loan Payoff Calculator - URL: https://boringtoolskit.com/student-loan-payoff/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Student loan payoff calculator: estimate your payoff months and see whether your monthly payment covers student loan interest. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Student loan payoff is simulated by applying a monthly payment to the balance and accruing interest at the monthly rate (annual rate ÷ 12). The calculator finds how many months (and total interest) it takes to clear the balance at that payment. - Assumptions: A fixed annual rate applied monthly (rate ÷ 12) on the outstanding balance. | Payments are made on time and go to interest then principal. | The estimate uses a simple monthly compounding model. - Sources: https://www.investopedia.com/terms/s/student-loan.asp | https://boringtoolskit.com/methodology/ ## Tool: Study Time Calculator - URL: https://boringtoolskit.com/study-time-calculator/ - Category: School & Education - Evidence: catalogue - Description: Study time calculator: hours per credit and per course versus the common 2-hours-per-credit rule. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Subnet Calculator - URL: https://boringtoolskit.com/subnet-calculator/ - Category: Text & Developer Tools - Evidence: authored-methodology - Description: Calculate network address, broadcast, usable host range, subnet mask, and wildcard for any IPv4 address and CIDR prefix. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: From an IP and CIDR prefix (/n): network address = IP AND mask; broadcast = network OR (~mask); address count = 2^(32−n); usable hosts = count − 2. Example: 192.168.1.10/24 → network 192.168.1.0, broadcast 192.168.1.255, 254 usable hosts. - Assumptions: IPv4 addressing and CIDR notation are used. | Standard network/broadcast reservations apply. | No VLSM or supernetting nuances are modeled. - Sources: https://en.wikipedia.org/wiki/Subnetwork | https://boringtoolskit.com/methodology/ ## Tool: Subscription Churn Impact Calculator - URL: https://boringtoolskit.com/subscription-churn-impact-calculator/ - Category: Seller & Business - Evidence: authored-methodology - Description: Model customer and recurring-revenue trajectory from constant churn, acquisition, ARPU, and horizon assumptions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Monthly churn requires churn × customers new customers/month just to hold steady. The tool projects the customer base and revenue month by month given churn, new customers, and ARPU. - Assumptions: Churn, new customers, and ARPU are constant monthly rates. | No seasonality or one-time events are modeled. | Revenue is ARPU × customer count per month. - Sources: https://en.wikipedia.org/wiki/Churn_rate | https://boringtoolskit.com/methodology/ ## Tool: Subscription Cost Calculator - URL: https://boringtoolskit.com/subscription-cost-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Subscription cost calculator: the real annual cost of your recurring subscriptions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sugar in Drinks Calculator - URL: https://boringtoolskit.com/sugar-in-drinks-calculator/ - Category: Health - Evidence: catalogue - Description: Sugar in drinks calculator: teaspoons and daily value from grams. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sump Pump Calculator - URL: https://boringtoolskit.com/sump-pump-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Sump pump calculator: gallons per minute needed for a basement. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sun & Moon Planner - URL: https://boringtoolskit.com/sun-moon-planner/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate sunrise, sunset, twilight, daylight, moon phase, moonrise, and moonset for a date and coordinates. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Shows the current moon phase and sun/moon timing data for planning: phase name, illumination, and relevant day/night timings. - Assumptions: The phase calculation uses standard lunar-cycle math. | Location-specific rise/set times are approximate. | The data is for planning, not navigation. - Sources: https://en.wikipedia.org/wiki/Lunar_phase | https://boringtoolskit.com/methodology/ ## Tool: Sunrise Sunset Calculator - URL: https://boringtoolskit.com/sunrise-sunset-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Sunrise sunset calculator: sunrise, sunset, and daylight hours for any city today plus the next week. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Sunscreen SPF Calculator - URL: https://boringtoolskit.com/sunscreen-spf-calculator/ - Category: Health - Evidence: catalogue - Description: Sunscreen SPF calculator: burn protection time and reapplication. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Surface Area Calculator - URL: https://boringtoolskit.com/surface-area-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the surface area of common 3D shapes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Cube: 6a². Sphere: 4πr². Cylinder: 2πr² + 2πrh. Cone: πr² + πr√(r² + h²). The tool computes surface area from the shape's dimensions. - Assumptions: The shape is a perfect geometric solid. | All dimensions are in the same units. | The shape is closed (all faces included). - Sources: https://en.wikipedia.org/wiki/Surface_area | https://boringtoolskit.com/methodology/ ## Tool: Swim Pace Calculator - URL: https://boringtoolskit.com/swim-pace-calculator/ - Category: Sports - Evidence: catalogue - Description: Swim pace calculator: minutes per 100 meters from distance and time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Swimming Calories Calculator - URL: https://boringtoolskit.com/swimming-calories-calculator/ - Category: Health - Evidence: catalogue - Description: Swimming calories calculator: calories burned swimming by weight and time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: T-Bill Yield Calculator - URL: https://boringtoolskit.com/t-bill-yield-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: T-Bill yield calculator: discount yield from face value, price, and days to maturity. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: T Test Calculator - URL: https://boringtoolskit.com/t-test-calculator/ - Category: Statistics - Evidence: catalogue - Description: T test calculator: two-sample t statistic and significance. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Tank Volume Calculator - URL: https://boringtoolskit.com/tank-volume-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Tank volume calculator: cylindrical tank capacity. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Tea Steep Calculator - URL: https://boringtoolskit.com/tea-steep-calculator/ - Category: Food & Cooking - Evidence: catalogue - Description: Tea steep calculator: water temperature and time by tea type. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Telescope Magnification Calculator - URL: https://boringtoolskit.com/telescope-magnification-calculator/ - Category: Astronomy - Evidence: catalogue - Description: Telescope magnification calculator: power from focal length and eyepiece. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Temperature Converter - URL: https://boringtoolskit.com/temperature-converter/ - Category: Converters - Evidence: catalogue - Description: Temperature converter: Celsius, Fahrenheit, and Kelvin. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Tempo Change Calculator - URL: https://boringtoolskit.com/tempo-change-calculator/ - Category: Music & Audio - Evidence: catalogue - Description: Tempo change calculator: new BPM after shifting pitch by semitones. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Term Life Insurance Calculator - URL: https://boringtoolskit.com/term-life-insurance-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Term life insurance calculator: coverage need using the DIME method. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Text Case Converter - URL: https://boringtoolskit.com/text-case/ - Category: Converters - Evidence: authored-methodology - Description: Change text case in one click — lower, upper, title, and sentence case. Free and private; nothing is uploaded. Paste and convert instantly. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Transforms text casing: lower (all lowercase), upper (all uppercase), title (first letter of each word uppercase), and sentence (first letter after each sentence period uppercase). - Assumptions: The transformation rule is applied mechanically. | Title case capitalizes every word's first letter. | Sentence case uses period boundaries. - Sources: https://en.wikipedia.org/wiki/Letter_case | https://boringtoolskit.com/methodology/ ## Tool: Thermal Equilibrium Calculator - URL: https://boringtoolskit.com/thermal-equilibrium-calculator/ - Category: Physics - Evidence: authored-methodology - Description: Calculate the final temperature when two objects reach thermal equilibrium. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Final temperature = (m₁·T₁ + m₂·T₂) ÷ (m₁ + m₂), assuming identical specific heat and no heat loss to the surroundings. - Assumptions: Both substances have the same specific heat capacity. | No heat is lost to the container or surroundings. | Positive masses are required; temperatures may differ in sign. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: TikTok Money Calculator - URL: https://boringtoolskit.com/tiktok-money-calculator/ - Category: Social Media - Evidence: authored-methodology - Description: Estimate TikTok earnings from views and creator fund rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Estimated earnings = (views ÷ 1,000) × creator fund rate. The rate defaults to $0.03 per 1,000 when left blank. - Assumptions: The creator fund rate is an estimate; payout varies by region, views, and program eligibility. | Earnings are gross before any platform or tax deductions. | The calculation only counts monetizable views. It does not include brand deals or live gifts. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Tile Calculator - URL: https://boringtoolskit.com/tile-calculator/ - Category: Construction & Measurement - Evidence: authored-methodology - Description: Estimate tiles and boxes required from surface and tile dimensions with waste. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Surface area = area length × area width. Tile area = tile length × tile width ÷ 144 (sq ft). Tiles needed = ceil(surface area × (1 + waste%) ÷ tile area). Boxes = ceil(tiles needed ÷ tiles per box). - Assumptions: The surface is rectangular. | Tiles are square or rectangular with dimensions entered in inches. | Waste covers cuts, breakage, and future repairs. - Sources: https://www.bobvila.com/articles/how-much-tile-do-i-need/ | https://boringtoolskit.com/methodology/ ## Tool: Tile Count Calculator - URL: https://boringtoolskit.com/tile-count-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Tile count calculator: tiles needed for a floor or wall. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Time Card Calculator - URL: https://boringtoolskit.com/time-card-calculator/ - Category: Time & Work - Evidence: authored-methodology - Description: Calculate work hours, lunch deductions, overtime, and estimated gross pay. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Daily hours = (end time − start time − lunch) in hours. Total = daily hours × days worked. Overtime: hours above the daily/weekly threshold paid at the overtime rate. - Assumptions: The schedule is the same each day. | One unpaid lunch break per day. | Overtime threshold is the entered value. - Sources: https://en.wikipedia.org/wiki/Timesheet | https://boringtoolskit.com/methodology/ ## Tool: Time to Decimal Calculator - URL: https://boringtoolskit.com/time-to-decimal-calculator/ - Category: Time & Work - Evidence: authored-methodology - Description: Convert hours and minutes to decimal hours for payroll and timesheets , and decimal hours back to hours and minutes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Decimal hours = hours + minutes ÷ 60. Decimal minutes = total minutes. The tool converts both directions: time ↔ decimal. - Assumptions: Standard 60-minute hour conversion. | No payroll rounding is applied. | The user converts in either direction. - Sources: https://en.wikipedia.org/wiki/Decimal_time | https://boringtoolskit.com/methodology/ ## Tool: Time Zone Meeting Planner - URL: https://boringtoolskit.com/time-zone-meeting-planner/ - Category: Time & Work - Evidence: authored-methodology - Description: Compare a meeting time across common world time zones using browser time-zone data. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Converts a meeting time in the organizer's zone to each participant's local time using IANA zone offsets, handling daylight saving automatically. - Assumptions: IANA zone names are used. | DST rules apply for the meeting date. | The chosen time is the organizer's local time. - Sources: https://en.wikipedia.org/wiki/Time_zone | https://boringtoolskit.com/methodology/ ## Tool: Timelapse Calculator - URL: https://boringtoolskit.com/timelapse-calculator/ - Category: Photo & Video - Evidence: catalogue - Description: Timelapse calculator: frames and finished clip length from capture interval and duration. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Timezone Converter - URL: https://boringtoolskit.com/timezone-converter/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Convert a time between cities and time zones worldwide with automatic daylight saving adjustment. Compare multiple zones at once, privately, no account. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Converts a wall time in one IANA time zone to another by resolving the instant (UTC) via each zone's offset, including daylight saving adjustments. - Assumptions: IANA zone names are used. | The entered time is local wall time in the source zone. | DST rules are applied for the date in question. - Sources: https://en.wikipedia.org/wiki/Time_zone | https://boringtoolskit.com/methodology/ ## Tool: Tip & Bill Split Calculator - URL: https://boringtoolskit.com/tip-bill-split-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate a tip, split a bill evenly, and make rounding choices explicit. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Per person = (subtotal + tax) × (1 + tip %) ÷ people, optionally rounding each share. The tool supports tipping on subtotal or on subtotal + tax. - Assumptions: The bill is split equally. | Tip and tax are entered as percentages. | The US tipping norm applies unless stated. - Sources: https://en.wikipedia.org/wiki/Gratuity | https://boringtoolskit.com/methodology/ ## Tool: Tire Pressure Calculator - URL: https://boringtoolskit.com/tire-pressure-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Tire pressure calculator: psi change with temperature. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Tire Size Comparison Calculator - URL: https://boringtoolskit.com/tire-size-comparison-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Tire size comparison calculator: diameter difference and speedometer error between two tire sizes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Tire Tread Depth Calculator - URL: https://boringtoolskit.com/tire-tread-depth-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Tire tread depth calculator: remaining life from tread depth. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Title Case Converter - URL: https://boringtoolskit.com/title-case-converter/ - Category: Converters - Evidence: catalogue - Description: Title case converter: convert any text to title case with proper small-word handling. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Titration Calculator - URL: https://boringtoolskit.com/titration-calculator/ - Category: Chemistry - Evidence: authored-methodology - Description: Calculate solution concentrations and equivalence points in titration. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Acid-base titration uses MₐVₐ × H⁺ = M_bV_b × OH⁻ at the equivalence point (moles of H⁺ = moles of OH⁻). - Assumptions: Molarity, volume, and the H⁺/OH⁻ per molecule are entered for the known side. | The calculation applies to the equivalence point of a complete neutralization. | The H⁺ per acid and OH⁻ per base values must be positive (e.g. 1 for HCl, 2 for H₂SO₄). - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Toilet Water Calculator - URL: https://boringtoolskit.com/toilet-water-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Toilet water calculator: gallons used per year. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Toll Cost Calculator - URL: https://boringtoolskit.com/toll-cost-calculator/ - Category: Travel - Evidence: catalogue - Description: Toll cost calculator: weekly and yearly toll spend from per-trip cost. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Torque Converter - URL: https://boringtoolskit.com/torque-converter/ - Category: Converters - Evidence: catalogue - Description: Torque converter: newton-meters, foot-pounds, inch-pounds. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Towing Capacity Calculator - URL: https://boringtoolskit.com/towing-capacity-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Towing capacity calculator: safe trailer weight from rated capacity minus payload and driver. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Transformer Calculator - URL: https://boringtoolskit.com/transformer-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Transformer calculator: output voltage or turns ratio for an ideal transformer. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Trapezoid Area Calculator - URL: https://boringtoolskit.com/trapezoid-area-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Trapezoid area calculator: area from bases and height. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Area = (a + b)/2 × h, where a and b are the parallel bases and h is the perpendicular height. - Assumptions: Standard geometric or arithmetic definitions apply. | Inputs use the units you choose. | Results are estimates, not professional advice. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Travel Budget Calculator - URL: https://boringtoolskit.com/travel-budget-calculator/ - Category: Travel - Evidence: catalogue - Description: Travel budget calculator: daily spending plus flights, hotels, and extras. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Travel Reimbursement Calculator - URL: https://boringtoolskit.com/travel-reimbursement-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Travel reimbursement calculator: mileage, meals and lodging claim. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Triangle Area Calculator - URL: https://boringtoolskit.com/triangle-area-calculator/ - Category: School & Education - Evidence: catalogue - Description: Triangle area calculator: area from base and height. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Triangle Calculator - URL: https://boringtoolskit.com/triangle-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Solve any triangle from its three sides: area, angles, height, inradius, circumradius, and perimeter. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Solves triangles from given sides/angles: area = ½ × base × height, and via Heron's formula from three sides. Angles sum to 180°. - Assumptions: Angles are in degrees. | Inputs satisfy the triangle inequality. | Standard Euclidean geometry applies. - Sources: https://en.wikipedia.org/wiki/Triangle | https://boringtoolskit.com/methodology/ ## Tool: Trig Calculator - URL: https://boringtoolskit.com/trig-calculator/ - Category: Everyday Calculators - Evidence: catalogue - Description: Trig calculator: sine, cosine, tangent of an angle. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: True Shooting Percentage Calculator - URL: https://boringtoolskit.com/true-shooting-percentage-calculator/ - Category: Sports - Evidence: catalogue - Description: True shooting percentage calculator: TS% accounting for free throws. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Tsp to Tbsp Converter - URL: https://boringtoolskit.com/tsp-tablespoon-converter/ - Category: Food & Cooking - Evidence: catalogue - Description: Tsp to tbsp converter: teaspoons, tablespoons, cups, ml. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Typing Test - URL: https://boringtoolskit.com/typing-test/ - Category: Text & Developer Tools - Evidence: authored-methodology - Description: Measure words per minute, accuracy, errors, and progress with a local timed typing test. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Words per minute = (words typed ÷ minutes elapsed). Accuracy = (correct characters ÷ total characters) × 100. The test times a practice passage and reports both. - Assumptions: The user types the passage in order. | WPM is calculated from the completed passage. | Accuracy counts character-level correctness. - Sources: https://en.wikipedia.org/wiki/Words_per_minute | https://boringtoolskit.com/methodology/ ## Tool: Unit Converter - URL: https://boringtoolskit.com/unit-conv/ - Category: Converters - Evidence: authored-methodology - Description: Convert common units instantly across length, area, weight, temperature, volume, speed, and pressure. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Converts between units by scaling to a base unit and then to the target (e.g., inches → meters → kilometers). Supported families: length, area, weight, temperature, volume, speed, pressure. - Assumptions: Standard SI-derived conversion factors are used. | Temperature uses the standard formulas. | Area-length conversions assume a constant width. - Sources: https://en.wikipedia.org/wiki/International_System_of_Units | https://boringtoolskit.com/methodology/ ## Tool: Unit Price Calculator - URL: https://boringtoolskit.com/unit-price-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Unit price calculator: price per unit to compare package sizes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: US to EU Size Converter - URL: https://boringtoolskit.com/us-eu-size-converter/ - Category: Converters - Evidence: catalogue - Description: US to EU size converter: general clothing conversion. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: US Weather Forecast - URL: https://boringtoolskit.com/us-weather-forecast/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Official National Weather Service forecast for US latitude and longitude coordinates. Enter exact coords for the authoritative federal NWS forecast, hourly a. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Pulls official National Weather Service forecasts: geocodes the location, then fetches current conditions and the multi-day forecast from NWS API endpoints. - Assumptions: The location is in the US. | The NWS API is reachable. | The forecast is used for planning, not safety-critical decisions. - Sources: https://en.wikipedia.org/wiki/National_Weather_Service | https://boringtoolskit.com/methodology/ ## Tool: Username Scrambler - URL: https://boringtoolskit.com/username-scrambler/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Generate randomized but memorable username ideas from your real name or email prefix, entirely in your browser. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Generates username variants from a base name using suffixes, numbers, separators, and random elements. - Assumptions: The base name is the user's starting point. | Variants are ideas, not availability checks. | Consistency across platforms is desirable. - Sources: https://en.wikipedia.org/wiki/Username | https://boringtoolskit.com/methodology/ ## Tool: UUID Generator - URL: https://boringtoolskit.com/uuid-generator/ - Category: Text & Developer Tools - Evidence: catalogue - Description: UUID generator: version 4 UUIDs for developers. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: UV Exposure Calculator - URL: https://boringtoolskit.com/uv-exposure-calculator/ - Category: Health - Evidence: catalogue - Description: UV exposure calculator: minutes until sunburn by UV index and Fitzpatrick skin type. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: VA Mortgage Calculator - URL: https://boringtoolskit.com/va-mortgage-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: VA mortgage calculator: VA loan with funding fee, no PMI. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Vacancy Rate Calculator - URL: https://boringtoolskit.com/vacancy-rate-calculator/ - Category: Real Estate - Evidence: catalogue - Description: Vacancy rate calculator: percentage of time a rental sits empty across a year. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Vacancy Rate Impact Calculator - URL: https://boringtoolskit.com/vacancy-rate-impact-calculator/ - Category: Finance & Investing - Evidence: authored-methodology - Description: Stress-test rental cash flow against vacancy. Enter normal cash flow and vacancy rate to see how lost rent eats your return. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Net occupied income = monthly rent × (1 − vacancy rate) − operating costs − fees. Vacancy reduces the rental income the property actually collects, so the metric shows the effective income after vacancy and costs. - Assumptions: Vacancy rate is the proportion of rent not collected, entered as a percentage. | Operating costs and fees are monthly figures. | The result is the effective monthly income after vacancy and direct costs. - Sources: https://www.investopedia.com/terms/v/vacancy-rate.asp | https://boringtoolskit.com/methodology/ ## Tool: Vacation Accrual Calculator - URL: https://boringtoolskit.com/vacation-accrual-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Vacation accrual calculator: PTO hours per pay period and per year. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Variance Calculator - URL: https://boringtoolskit.com/variance-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate sample or population variance from a data set. Enter values to see variance, standard deviation, and the sum of squared deviations. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Variance σ² (population) = Σ(x − mean)² ÷ n. Sample variance s² = Σ(x − mean)² ÷ (n − 1). - Assumptions: Variance needs at least two numbers. | The sample formula (÷ n−1) better estimates a larger population from a smaller sample. | The population formula (÷ n) applies when the data is the complete set. - Sources: https://www.itl.nist.gov/div898/handbook/ | https://boringtoolskit.com/methodology/ ## Tool: Vehicle Depreciation Calculator - URL: https://boringtoolskit.com/vehicle-depreciation-calculator/ - Category: Vehicles - Evidence: catalogue - Description: Vehicle depreciation calculator: projected value after years of ownership at a depreciation rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Velocity Calculator - URL: https://boringtoolskit.com/velocity-calculator/ - Category: Physics - Evidence: authored-methodology - Description: Calculate velocity from distance and time, with km/h and mph conversions. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Velocity (v) = distance ÷ time. Conversions: km/h = v × 3.6; mph = v × 2.236936. - Assumptions: Distance is in meters and time in seconds. | Velocity assumes constant motion over the interval. | Positive values are required. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Vertical Jump Calculator - URL: https://boringtoolskit.com/vertical-jump-calculator/ - Category: Sports - Evidence: catalogue - Description: Vertical jump calculator: jump height from hang time (free-flight physics). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Video File Size Calculator - URL: https://boringtoolskit.com/video-file-size-calculator/ - Category: Photo & Video - Evidence: catalogue - Description: Video file size calculator: estimate file size from bitrate, resolution, frame rate, and duration. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Video Watch Time Calculator - URL: https://boringtoolskit.com/video-watch-time-calculator/ - Category: Social Media - Evidence: authored-methodology - Description: Calculate total video watch hours from views and average duration. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Total watch time in seconds = views × average view duration. Hours = seconds ÷ 3,600. Days = hours ÷ 24. - Assumptions: Average view duration is the user's estimate from analytics. | Watch time is summed across all views. | Retention is assumed constant; real watch time varies by video length and audience. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Vinyl RPM Calculator - URL: https://boringtoolskit.com/vinyl-rpm-calculator/ - Category: Music & Audio - Evidence: authored-methodology - Description: Calculate pitch change when a record plays at the wrong turntable speed. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Pitch change % = (actual speed ÷ standard RPM − 1) × 100. Speed ratio = actual ÷ standard. - Assumptions: The standard speed is 33, 45, or 78 RPM (entered). | Pitch and duration change proportionally with speed. | The actual turntable speed is the user's input. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Vitamin D Calculator - URL: https://boringtoolskit.com/vitamin-d-calculator/ - Category: Health - Evidence: catalogue - Description: Vitamin D calculator: IU to mcg conversion with daily reference. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: VO2 Max Calculator - URL: https://boringtoolskit.com/vo2-max-calculator/ - Category: Health - Evidence: catalogue - Description: VO2 max calculator: estimate aerobic fitness from a 12-minute run or resting heart rate. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: VO2 Max Calculator - URL: https://boringtoolskit.com/vo2max-calculator/ - Category: Health - Evidence: catalogue - Description: VO2 max calculator: estimate from a 12-minute Cooper test. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Voltage Drop Calculator - URL: https://boringtoolskit.com/voltage-drop-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Estimate voltage drop in a wire run based on length, current, and wire gauge. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Voltage drop = 2 × one-way length × resistance per 1,000 ft × amps ÷ 1,000. The tool uses standard wire-gauge resistances and reports the drop as volts and % of supply. - Assumptions: Copper conductors at standard resistances. | The run is the one-way length (doubled internally). | Ambient temperature and load power factor are typical. - Sources: https://en.wikipedia.org/wiki/Voltage_drop | https://boringtoolskit.com/methodology/ ## Tool: Volume Calculator - URL: https://boringtoolskit.com/volume-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the volume of common 3D shapes. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Cube: a³. Sphere: (4/3)πr³. Cylinder: πr²h. Cone: (1/3)πr²h. The tool computes the interior space of the chosen shape. - Assumptions: The shape is a perfect geometric solid. | All dimensions are in the same units. | The result is interior volume (wall thickness ignored). - Sources: https://www.mathsisfun.com/geometry/volume.html | https://boringtoolskit.com/methodology/ ## Tool: Volume Converter - URL: https://boringtoolskit.com/volume-converter/ - Category: Converters - Evidence: catalogue - Description: Volume converter: gallons, liters, quarts, cups, fluid ounces, milliliters. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Wainscoting Calculator - URL: https://boringtoolskit.com/wainscoting-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Wainscoting calculator: panels needed for a wall. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Waist Hip Ratio Calculator - URL: https://boringtoolskit.com/waist-hip-ratio-calculator/ - Category: Health - Evidence: catalogue - Description: Waist to hip ratio calculator: WHR and health risk category. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Waist to Height Ratio Calculator - URL: https://boringtoolskit.com/waist-to-height-ratio-calculator/ - Category: Health - Evidence: catalogue - Description: Waist-to-height ratio calculator: assess abdominal obesity risk from waist and height. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Walking Calories Calculator - URL: https://boringtoolskit.com/walking-calories-calculator/ - Category: Health - Evidence: catalogue - Description: Walking calories calculator: calories burned walking by weight and time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Wallpaper Calculator - URL: https://boringtoolskit.com/wallpaper-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Wallpaper calculator: rolls needed from wall area, roll coverage, and pattern waste. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Wash Sale Calculator - URL: https://boringtoolskit.com/wash-sale-calculator/ - Category: Finance & Investing - Evidence: catalogue - Description: Wash sale calculator: disallowed loss and adjusted basis after a repurchase. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Water Heater Sizing Calculator - URL: https://boringtoolskit.com/water-heater-sizing-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Water heater sizing calculator: first-hour rating from peak hot water uses. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Daily Water Intake Calculator - URL: https://boringtoolskit.com/water-intake-calculator/ - Category: Health - Evidence: catalogue - Description: Daily water intake calculator: estimate hydration needs from body weight and activity. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Water Pressure Calculator - URL: https://boringtoolskit.com/water-pressure-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Water pressure calculator: static pressure from elevation head. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Watts to Amps Calculator - URL: https://boringtoolskit.com/watts-to-amps-calculator/ - Category: Energy & Electrical - Evidence: authored-methodology - Description: Convert watts to amps for DC, single-phase AC, or three-phase AC with voltage and power factor. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: DC: I = P ÷ V. Single-phase AC: I = P ÷ (V × PF). Three-phase AC: I = P ÷ (√3 × V × PF). - Assumptions: Entered watts represent real power. | Three-phase voltage is treated as line-to-line voltage. | Efficiency, starting current, harmonics, and code sizing factors are excluded. - Sources: https://www.nist.gov/pml/owm/metric-si/si-units | https://www.osha.gov/electrical ## Tool: Wave Calculator - URL: https://boringtoolskit.com/wave-calculator/ - Category: Physics - Evidence: authored-methodology - Description: Calculate wave speed from frequency and wavelength (v = fλ). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Wave speed = frequency × wavelength. Units: m/s, Hz, and m. - Assumptions: Frequency is in hertz and wavelength in meters. | The calculation assumes the wave travels in a uniform medium. | Positive frequency and wavelength are required. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: Weather Lookup - URL: https://boringtoolskit.com/weather-lookup/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Current weather and 7-day forecast for any city worldwide. Temperature, feels-like, precipitation, wind, and UV from Open-Meteo. Private, no account. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Pulls live weather from the Open-Meteo API: geocodes the city, then fetches current conditions and a 7-day forecast (temperature, precipitation, wind, and more). - Assumptions: The city geocodes successfully. | Open-Meteo is reachable. | The forecast is used for planning, not safety-critical decisions. - Sources: https://en.wikipedia.org/wiki/Weather | https://boringtoolskit.com/methodology/ ## Tool: Weight Converter - URL: https://boringtoolskit.com/weight-converter/ - Category: Converters - Evidence: catalogue - Description: Weight converter: pounds, kilograms, ounces, grams, and stones. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Weight Loss Timeline Calculator - URL: https://boringtoolskit.com/weight-loss-timeline-calculator/ - Category: Health - Evidence: catalogue - Description: Weight loss timeline calculator: how long a healthy weekly deficit will take. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Weighted Average Calculator - URL: https://boringtoolskit.com/weighted-average-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate a weighted average (weighted mean). Enter values and weights to combine scores or grades that count differently. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Weighted average = Σ(value × weight) ÷ Σ(weight). - Assumptions: The number of values must equal the number of weights. | Weights must sum above zero. | Weights are relative and do not need to sum to 100. - Sources: https://www.itl.nist.gov/div898/handbook/ | https://boringtoolskit.com/methodology/ ## Tool: Weighted Grade Calculator - URL: https://boringtoolskit.com/weighted-grade-calculator/ - Category: School & Education - Evidence: catalogue - Description: Weighted grade calculator: final grade from category scores and weights, with letter grade. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Wet Bulb Temperature Calculator - URL: https://boringtoolskit.com/wet-bulb-temperature-calculator/ - Category: Geography - Evidence: catalogue - Description: Wet bulb temperature calculator: wet-bulb from temperature and humidity (Stull 2011). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Win Loss Percentage Calculator - URL: https://boringtoolskit.com/win-loss-percentage-calculator/ - Category: Sports - Evidence: catalogue - Description: Win-loss percentage calculator: winning percentage with ties counted as half a win. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Win Streak Probability Calculator - URL: https://boringtoolskit.com/win-streak-probability-calculator/ - Category: Gaming - Evidence: catalogue - Description: Win streak probability calculator: odds of winning N games in a row. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Wind Chill Calculator - URL: https://boringtoolskit.com/wind-chill-calculator/ - Category: Geography - Evidence: catalogue - Description: Wind chill calculator: feels-like temperature from air temperature and wind speed. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Wind Turbine Output Calculator - URL: https://boringtoolskit.com/wind-turbine-output-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Wind turbine output calculator: power from blade size and wind speed. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Window Size Calculator - URL: https://boringtoolskit.com/window-size-calculator/ - Category: Construction & Measurement - Evidence: catalogue - Description: Window size calculator: recommended window area for a room. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Wire Size Calculator - URL: https://boringtoolskit.com/wire-size-calculator/ - Category: Energy & Electrical - Evidence: catalogue - Description: Wire size calculator: suggested AWG for a current and run length (copper, 3% drop target). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Word Counter - URL: https://boringtoolskit.com/word-counter/ - Category: Text & Developer Tools - Evidence: authored-methodology - Description: Count words, characters, sentences, and reading time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Word count = tokens split by whitespace (non-empty). Character count = length of the text including spaces. The tool counts instantly as you type or paste. - Assumptions: Whitespace separates words. | Character count includes spaces. | The count updates on paste and typing. - Sources: https://en.wikipedia.org/wiki/Word_count | https://boringtoolskit.com/methodology/ ## Tool: Words Per Minute Calculator - URL: https://boringtoolskit.com/words-per-minute-calculator/ - Category: Time & Work - Evidence: catalogue - Description: Words per minute calculator: typing speed from characters and time. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Work Calculator - URL: https://boringtoolskit.com/work-calculator/ - Category: Physics - Evidence: catalogue - Description: Work calculator: work done by a force over a distance (W = F \u00d7 d). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Work and Power Calculator - URL: https://boringtoolskit.com/work-power-calculator/ - Category: Physics - Evidence: authored-methodology - Description: Calculate mechanical work (W = F·d) and power output (P = W/t). - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Work (W) = force × distance. Power (P) = work ÷ time. Units: joules (J) and watts (W). - Assumptions: Force is in newtons, distance in meters, time in seconds. | Power uses the time entered; if zero it defaults to 1 s for an instantaneous reading. | Positive force and distance are required. - Sources: https://www.nist.gov/pml/owm/metric-si | https://boringtoolskit.com/methodology/ ## Tool: World Clock - URL: https://boringtoolskit.com/world-clock/ - Category: Time & Work - Evidence: authored-methodology - Description: Compare the current local date, time, UTC offset, and daylight-saving context across selected IANA time zones. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Shows the current time in major world cities and time zones simultaneously, applying each zone's offset and daylight saving rules. - Assumptions: The system clock is accurate. | City zones use current IANA offsets. | Times are read at the moment of viewing. - Sources: https://en.wikipedia.org/wiki/Time_zone | https://boringtoolskit.com/methodology/ ## Tool: XP Level Calculator - URL: https://boringtoolskit.com/xp-level-calculator/ - Category: Gaming - Evidence: catalogue - Description: XP level calculator: total XP needed and progress percentage toward the next level. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: XP to Level Calculator - URL: https://boringtoolskit.com/xp-to-level-calculator/ - Category: Gaming - Evidence: catalogue - Description: XP-to-level calculator: experience needed for the next level on linear or quadratic curves. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Yard to Feet Converter - URL: https://boringtoolskit.com/yard-feet-converter/ - Category: Converters - Evidence: catalogue - Description: Yard to feet converter: yards, feet, inches. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Yarn Weight Converter - URL: https://boringtoolskit.com/yarn-weight-converter/ - Category: Converters - Evidence: catalogue - Description: Yarn weight converter: US names to wraps per inch and needle size. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: YouTube Revenue Calculator - URL: https://boringtoolskit.com/youtube-revenue-calculator/ - Category: Social Media - Evidence: authored-methodology - Description: Estimate YouTube revenue from monthly views and RPM. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Estimated revenue = (views ÷ 1,000) × RPM. RPM defaults to $2.00 when left blank. - Assumptions: RPM (revenue per 1,000 views) is the user's estimate; actual RPM varies by niche, geography, ads, and monetization status. | Revenue is gross before platform share and taxes. | The estimate applies to monetized watch-page views only. - Sources: https://boringtoolskit.com/methodology/ ## Tool: Z-Score Calculator - URL: https://boringtoolskit.com/z-score-calculator/ - Category: Everyday Calculators - Evidence: authored-methodology - Description: Calculate the z-score (standard score) for a value. Enter the raw score, mean, and standard deviation to see how many SDs above or below the mean it sits. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. - Formula or method: Z-score = (value − mean) ÷ standard deviation. A positive z means the value is above the mean; negative means below. - Assumptions: Standard deviation must be above zero. | The score is assumed to come from a roughly symmetric distribution for the percentile reading. | The z-score standardizes a value relative to the mean and spread of its data set. - Sources: https://www.itl.nist.gov/div898/handbook/ | https://boringtoolskit.com/methodology/ ## Tool: Z Test Calculator - URL: https://boringtoolskit.com/z-test-calculator/ - Category: Statistics - Evidence: catalogue - Description: Z test calculator: z-score for a sample mean vs a known population. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: ZIP Code Lookup - URL: https://boringtoolskit.com/zip-code-lookup-calculator/ - Category: Converters - Evidence: catalogue - Description: ZIP code lookup: city, county and state for any US ZIP, or ZIPs for a city. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: ZIP Code County Lookup - URL: https://boringtoolskit.com/zip-county-lookup-calculator/ - Category: Converters - Evidence: catalogue - Description: ZIP code county lookup: county, FIPS code, and population for any US ZIP. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: ZIP Code Timezone Calculator - URL: https://boringtoolskit.com/zip-timezone-calculator/ - Category: Converters - Evidence: catalogue - Description: ZIP Code timezone calculator: find the timezone and current local time for any US ZIP. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Zodiac Compatibility Calculator - URL: https://boringtoolskit.com/zodiac-compatibility-calculator/ - Category: Astrology - Evidence: catalogue - Description: Zodiac compatibility calculator: sun-sign match score by element and modality, entertainment only. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Zodiac Element Calculator - URL: https://boringtoolskit.com/zodiac-element-calculator/ - Category: Astrology - Evidence: catalogue - Description: Zodiac element calculator: element, modality, and ruling planet for any sun sign. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request. ## Tool: Zodiac Sign Calculator - URL: https://boringtoolskit.com/zodiac-sign-calculator/ - Category: Astrology - Evidence: catalogue - Description: Zodiac sign calculator: find your sun sign, element, modality, and ruling planet from a birth date. - Privacy: Inputs and results stay in this browser unless the page clearly labels an external request.