Compound interest calculator●
See how your money grows when interest earns interest, with optional monthly deposits.
The result updates as you type. Nothing you enter leaves this page.
Future value
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Year by year
| Year | Deposits | Interest | Balance |
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Amounts are calculated in this browser tab and are never sent anywhere.
How compound interest works
With compound interest, the interest you earn is added to the balance and starts earning interest too. Without deposits the balance after t years is the starting amount times (1 + r/n) to the power of n times t, where r is the yearly rate and n is how many times a year interest compounds. Monthly deposits are added on top and earn interest from the day they go in. The more often interest compounds and the longer you leave it, the faster the balance grows.
Loan calculator →Common questions
What is the compound interest formula?
A = P (1 + r/n)^(n t), where P is the starting amount, r the yearly rate as a decimal, n the compounding periods per year and t the years. This calculator also handles monthly deposits.
How is compound interest different from simple interest?
Simple interest is paid only on the starting amount. Compound interest is paid on the starting amount plus the interest already earned, so growth speeds up over time.
Does compounding more often make a big difference?
A small one. At 7% a year, monthly compounding ends slightly higher than yearly compounding. Time and regular deposits matter far more.
Does this include inflation, fees or tax?
No. The result is a plain projection at a fixed rate. Real returns change from year to year and are reduced by fees, tax and inflation.
Is anything sent anywhere?
No. The calculation runs in your browser.