Investment Calculator
Investment Calculator — calculate future value, total returns, and year-by-year growth for any investment. Free, no signup.
Year-by-year growth
| Year | Annual contribution | Balance | Total return |
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About Investment Calculator
The Investment Calculator projects the future value of any investment using compound interest. Enter a lump sum, a monthly contribution, an expected annual return, and a time horizon — the result shows your projected ending balance, total returns, and return on investment, with a year-by-year breakdown on demand.
How compound interest works
Your balance earns a return each period. Those returns are added to the balance, which then earns returns itself. This compounding effect — interest on interest — is what makes long investment horizons so powerful.
The formula for a lump sum: FV = P × (1 + r/n)^(n×t)
For regular contributions, each payment also compounds from the moment it is made. The total future value is the sum of the lump-sum growth and the accumulated contributions.
Monthly contributions vs lump sum
A single large deposit benefits from the full compounding period. Monthly contributions start small but grow: a $500/month contribution at 8% for 10 years grows to roughly $91,000 — nearly triple the $60,000 invested. The earlier each contribution goes in, the longer it compounds.
Compounding frequency
Monthly compounding (the default) applies interest 12 times a year and is standard for most investment accounts and savings products. Quarterly and annual options are available for fixed deposits or bonds that compound less frequently.
What this calculator does not cover
Results are nominal — not adjusted for inflation, taxes, or fees. For real purchasing power, subtract your expected inflation rate from the return rate. For net-of-fee returns, use your investment’s net return (return after expense ratio). Variable returns (stocks, actively managed funds) will not match a fixed-rate projection exactly; use the calculator as a planning estimate, not a guarantee.
All calculations happen in your browser. No data is sent to TheToolBus. Free, no signup.
Frequently asked questions
Enter your initial investment (lump sum), monthly contribution, expected annual return rate, and investment period. The calculator applies the compound interest formula — future value of lump sum plus future value of contributions — to project your ending balance and total returns. Click Calculate to see the result.
Compound interest is interest earned on both your principal and previously accumulated interest. Each period, your returns are added to the balance and then earn returns themselves. Over long periods this creates exponential growth — a key reason starting early matters more than the amount invested.
Common benchmarks: US equities (S&P 500) ~10% nominal, ~7% real after inflation; global equities ~7–9%; bonds ~2–4%; high-yield savings accounts ~4–5%. For long-term equity projections, 7–8% is a widely used estimate. Past returns do not guarantee future results.
Compounding frequency determines how often interest is added to your balance. Monthly compounding applies interest 12 times a year; quarterly, 4 times; annually, once. More frequent compounding yields slightly higher returns: $10,000 at 8% for 10 years grows to $22,196 with monthly compounding vs $21,589 with annual compounding.