Compound Interest Calculator
Calculate how an investment grows with compound interest and regular monthly contributions, with a year-by-year breakdown.
This tool runs entirely in your browser.
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How to use the Compound Interest Calculator
- 1Enter the starting amount, monthly contribution, interest rate and years.
- 2Choose how often interest compounds.
- 3Read the final balance and yearly table.
What is the Compound Interest Calculator?
Compound interest earns interest on previous interest. With no contributions, A = P × (1 + r/n)^(n × t). The “rule of 72” estimates doubling time: 72 ÷ annual rate (%) years.
Frequently asked questions
Does it account for inflation or taxes?
No. For a rough real return, subtract the expected inflation rate from the interest rate.
Is the Compound Interest Calculator free and private?
Yes. The Compound Interest Calculator is free, needs no account, and runs entirely in your browser. What you type is never sent to a server or stored.
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