Compound Interest Calculator
Enter your starting amount, monthly contribution, expected return, and time horizon to see how far compounding can grow your money. Figures assume monthly compounding with contributions added at month end.
How it works
This uses monthly compounding: your starting amount and each monthly contribution grow by (annual return ÷ 12) every month. The return rate is an assumption, not a guarantee — real market returns vary every year.
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Frequently Asked Questions
How is compound interest calculated here?
This calculator uses monthly compounding: your starting amount and each monthly contribution grow by (annual return ÷ 12) every month.
Is a 7% return realistic?
It is a common rough assumption for long-run stock markets, but not a guarantee. Real returns vary every year and some years are negative.
Does compounding frequency change the result much?
Less than people expect. At the same annual rate, the difference between monthly and yearly compounding is small.
This calculator is an educational estimate, not individual investment advice. It does not account for taxes, fees, or inflation.