About Compound Interest Calculator

Compound Interest Calculator shows how money grows when returns earn returns. Enter a starting amount, monthly contribution, expected annual return, and time horizon, then see your final balance, total interest earned, and a year-by-year growth chart instantly.

See compounding, not just totals

The growth chart shows the classic compounding curve: amber is the money you put in, green is what it becomes. A breakdown splits your final balance into starting amount, contributions, and interest earned, with your overall growth multiple.

Flexible compounding

Choose daily, monthly, quarterly, or annual compounding, and toggle the year-by-year table to see contributions, interest, and balance for every year.

Who runs this site

Compound Interest Calculator HQ is built and maintained by Nathan Hays, who makes a family of free, single-purpose web tools. He is not a broker, advisor, or bank and the site sells nothing; its only job is to compute honest projections with math you can check. Questions and corrections are welcome at [email protected].

Private and free

Every calculation runs locally in your browser. Nothing you enter is uploaded, stored, or sent anywhere. No sign-up, nothing to install. For details on the cookies used by advertising, see our Privacy Policy.

Important disclaimer

This calculator is for general informational and educational purposes only. It does not provide, and must not be relied on as, investment advice, tax advice, legal advice, or financial advice.

• Estimates only. Results assume a constant rate of return with no taxes, fees, or inflation. Real investment returns vary year to year and can be negative.
• No guarantees. Past performance never guarantees future results. No projection here is a prediction of what any investment will actually do.
• Taxes and fees. Taxes and fees matter. Investment gains may be taxable (the sister capital gains tax calculator covers that side) and funds charge fees; both reduce real-world results and are not modeled here.
• No professional relationship. Using this site does not create any advisor-client, accountant-client, or attorney-client relationship.
• No liability. We accept no liability for decisions made or actions taken based on this tool's output.

For real investment decisions (retirement planning, choosing funds, asset allocation), consult a qualified, licensed financial advisor.