Calculate compound interest growth with any principal, rate, and compounding frequency. See year-by-year breakdown, total interest earned, and investment multiples. Pure client-side, instant results.
This compound interest calculator helps you visualize how your money grows over time with the power of compounding. Whether you're planning for retirement, saving for a goal, or evaluating an investment, see exactly how much you'll earn with different rates, frequencies, and contribution levels. All calculations happen in your browser — your financial data never leaves your device.
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, compound interest "compounds" over time, leading to exponentially faster growth. This is why Einstein reportedly called it "the eighth wonder of the world."
The more frequently interest compounds, the more you earn. For example, 7% compounded monthly yields slightly more than 7% compounded annually. With continuous compounding, interest is calculated infinitely often, producing the maximum possible return for a given rate.
The standard formula is A = P(1 + r/n)^(nt), where A is the final amount, P is the principal, r is the annual rate, n is the compounding frequency per year, and t is the number of years. For continuous compounding, the formula becomes A = Pe^(rt).
Yes! Enter an optional monthly contribution amount, and the calculator will factor it into the future value using the future value of an annuity formula combined with compound growth.