Math, Science & Calculators · Free Tool

Compound Interest Calculator

See how savings or investments grow over time — with optional regular contributions and any compounding frequency. Live results, all in your browser.

Starting amount

Annual rate %

Years

Compounding

Regular contribution

Contribution frequency

Final balance

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You put in

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Interest earned

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How it works

Compound interest earns interest on your interest. The starting amount grows by P(1 + r/n)^nt, where r is the annual rate, n the number of times it compounds per year, and t the years. Regular contributions are added each compounding period and grow as an annuity. All maths runs on your device — nothing is sent anywhere.