Calculation details
Planning estimate only, not financial, tax, or legal advice. Verify assumptions and current rules before making decisions.
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Use this result
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What does this calculator estimate?
A $10,000 lump sum at 6 percent compounded monthly for 20 years grows to about $33,102. The balance compounds at the annual rate divided by 12 each month, and deposits are applied at the selected timing.
- Monthly compounding uses rate / 12 on the balance each month (Investor.gov).
- Deposit timing at the start of the month earns one extra compounding period versus the end.
- Future value grows exponentially with time because interest earns interest.
What future value tells you
Future value is what a sum of money becomes at a given return — the core of savings and investment planning. It shows the power of compounding: $10,000 at 7% doubles in about 10 years (rule of 72).
Limitations to watch for
The projection assumes a constant return — real investments fluctuate, so treat it as a scenario, not a promise. Inflation isn't subtracted: the nominal value overstates future purchasing power. The tool is for lump sums; add the DCA calculator for contributions.
How to use it in practice
Use it to project savings targets, compare investment options, and understand compounding. Subtract an inflation assumption (2–3%) for a 'real' estimate. Use conservative rates for planning.
['Enter the present value.', 'Enter the expected annual return and years.', 'Choose the compounding frequency and read the future value.']
The future value formula
Future value = present value × (1 + r)^n, where r is the rate per period and n the number of periods. $10,000 at 7 percent for 10 years: 10,000 × 1.07^10 ≈ $19,672. With monthly contributions, each deposit compounds separately and sums — the calculator handles both.
Lump sum vs. contributions
A lump sum grows on the whole balance immediately; contributions add new principal over time. $10,000 today plus $200 monthly at 7 percent for 10 years reaches about $51,000 — $24,000 of contributions and $17,000 of growth. The calculator separates the sources.
Inflation-adjusted value
Nominal future value overstates purchasing power. At 3 percent inflation, $19,672 in 10 years buys about $14,640 in today's dollars. The calculator shows both nominal and real values so the number is honest about what it will buy.
Rate sensitivity
The rate dominates long horizons: $10,000 at 5 percent for 30 years is about $43,200; at 8 percent it is about $100,600. The difference is entirely the rate. The calculator makes the sensitivity visible when you compare scenarios.
A worked example
$5,000 invested monthly at $100 for 20 years at 7 percent: contributions $24,000, growth to about $54,000 total. Starting 5 years earlier with the same $100 monthly adds roughly $20,000 more at the end — time is the biggest input, and the calculator shows exactly how big.
How this calculator works
Formula
Future value = present value × (1 + r ÷ n)^(n × t), where r is the annual return, n the compounding periods per year, and t the years.
Worked example
$10,000 invested at 7% for 10 years grows to about $19,672 (compounded annually).
Assumptions to verify
- A constant rate of return.
- No contributions or withdrawals.
- Compounding at the selected frequency.
Frequently asked questions
What is future value?
What a sum of money becomes at a given return: $10,000 at 7% for 10 years ≈ $19,672.
How is it calculated?
FV = PV × (1 + r/n)^(n×t). The exponent is where compounding does its work.
What is the rule of 72?
72 ÷ rate ≈ years to double. At 7%, money doubles in about 10.3 years.
Does this include inflation?
No — the result is nominal. Subtract 2–3% for a real (purchasing-power) estimate.
Is the return guaranteed?
No — the tool projects math under your assumed rate. Use conservative scenarios.
What about regular contributions?
Use the DCA investment calculator — this tool models a single lump sum.
How do I choose a rate?
Broad index funds have historically returned 7–10% nominal over long periods; use less for conservative planning.
How do I calculate future value?
Present value × (1 + rate)^periods, plus the compounded value of any contributions.
What return should I use?
Historically 6–8% for broad equity portfolios; test a range for sensitivity.
Does inflation matter?
Yes — adjust for inflation to see what the future value will actually buy.
What grows faster, rate or time?
Both compound, but time multiplies every rate — starting early is the strongest lever.
Cite this tool
BoringToolsKit. “Future Value Calculator.” boringtoolskit.com/future-value-calculator/ (reviewed 2026-08-25). Free to reference in articles, syllabi, and answer posts with a link.
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