BoringToolsKit — everyday calculators & tools
Whatever you need to figure out today — a payment, a fee, a measurement — type it below. 981 free tools, every formula shown, everything runs in your browser.
Live matches appear below · ↑ ↓ selects · Enter opens a tool · search opens all matches
Try an example
One tap opens the tool with a real scenario pre-filled — results appear instantly. Example: 20% of $85.50 = $17.10 tip → $102.60 total → $51.30 each.
Calculator hubs
Grouped collections for the money, home, health, time, seller, construction, and energy decisions people actually run.
New and updated tools, ordered by their authored review date.
Decimal to fraction calculator: convert any decimal into a simplified fraction or mixed number, with the…
Fraction to decimal calculator converts any fraction to its decimal value, with repeating decimals and steps…
Round up/down calculator: nearest multiple in both directions. Free round up down calculator with the formula…
Rounding calculator: round decimals to the nearest tenth, hundredth, ten, hundred, or any place value you…
Significant figures calculator: round any number to your chosen sig figs with step-by-step counting rules…
401k employer match calculator: estimate your contributions, employer match, and unclaimed match you are…
Your tools, in your browser
Picked up where you left off. Nothing is uploaded — this list lives only on this device.
Find your tools by goal
Pick a goal and we'll line up the tools in the order you'll use them. Search still works any time.
🔥 Trending now · 🍂 Seasonal · unmarked = Evergreen — refreshed from analytics and what people are into.
Back to school 2026
Plan the semester: estimate your GPA, work out a school budget, and see what a grade actually takes. Free, no signup, runs in your browser.
Open the calculators →Browse the catalogue or search by the job you need to do.
All 981 available tools load in alphabetical batches as you scroll.
Use it without an app
Add BoringToolsKit to your phone's home screen and every tool you open stays usable with no connection — perfect for flights, commutes, and spotty signal. A pocket calculator that doesn't need to phone home.
How BoringToolsKit works
Every BoringToolsKit calculator runs in your browser — nothing you type is sent to a server. That matters for money, health, and school totals you'd rather keep private. Each tool shows its formula, a worked example, and the assumptions behind the result, so you know what the number assumes rather than trusting a black box. Here's how to get the most from the common decision areas.
Work out a mortgage payment or loan term, check how much you'll actually take home after deductions, or set a savings goal and see the monthly contribution it takes. Start with a payment estimate, then use the amortization and payoff tools to see the cost of a longer term.
From rent affordability to household budgets and energy costs, these tools help you price a decision before you commit. Estimate a bill, compare an appliance's running cost, and see how a renovation or a new purchase changes the yearly number.
Estimate daily calorie needs, BMI and body-fat ranges, and pacing for exercise. These are planning anchors — not medical advice — so read the displayed assumptions and confirm important totals with a professional.
Convert an hourly rate to an annual salary, work out overtime and a pay raise, and plan time for tasks. Good for a quick number before a conversation about pay or a deadline.
Marketplace and payment fees can swallow a margin. Estimate net profit after Amazon, eBay, Etsy, or Shopify fees, work out a break-even, and price a product with the fee structure shown in the result.
Estimate materials and waste for a concrete, flooring, or roofing job; compare energy use and cost; and size up a rental or a flip with cap rate, cash flow, and after-repair value. Each result lists the rate or input it assumes.
Every result is calculated locally with the inputs shown. Verify anything that affects a real commitment against current rates, local rules, or a qualified professional — the tools are planning aids, not guarantees. See the methodology for the formulas and reference cases behind each family.
BoringToolsKit is a free suite of 981 browser-based calculators, converters, and timers for finance, health, cooking, construction, and everyday work. Every tool runs locally in your browser: no signup, no uploads, and nothing you enter is stored or sent to a server. Each result shows the formula and inputs it assumes, so the math is checkable.
Yes — every tool is free with no account required. The site is funded by ads and affiliate links, never by paywalls or data collection.
No. Calculations run entirely in your browser using JavaScript. Your inputs, files, and results never leave your device — nothing is uploaded, logged, or shared.
Each tool shows the exact formula and inputs it uses, and results are verified against worked reference cases documented in the methodology pages. They are planning aids: verify anything that affects a real financial or legal commitment against current rates or a qualified professional.
Most do. Because the logic is client-side, tools keep working once the page has loaded, even if your connection drops. Timers and calculators are fully offline-capable.
Yes — most tools offer a free embeddable widget. Open a tool and look for the Embed option to get a snippet that runs the same private, in-browser logic on your page.
Thanks for coming by.
If a calculator saved you a minute (or seconds), consider a one-off coffee / matcha / lemonade / bottle of H2O / juice box. BoringToolsKit stays free and private either way.
☕ Buy me a coffee