About this calculator
Compound interest is interest on both principal and accumulated interest — the foundation of long-term wealth building.
Formula
A = P(1 + r/n)^(nt)
How to use this calculator
Enter principal, rate, time and compounding frequency.
Frequently asked questions
What is the Rule of 72?
Divide 72 by the annual return rate to estimate years to double your money. At 12% return, money doubles in roughly 6 years.
Are these calculators free to use?
Yes. All calculators are free, require no signup, and run entirely in your browser.
Results are estimates for planning purposes only — not investment, tax or legal advice. Verify rates on official sources before acting. Compare brokers on our best stock brokers guide or use the brokerage calculator.