Compound Interest Calculator
The Compound Interest Calculator shows how your savings or investment grows when interest is earned not just on your principal, but on previously earned interest too.
The compound interest formula
Where A is the final balance, P is the principal, r is the annual interest rate, n is the number of times interest compounds per year, and t is time in years. If you add regular monthly deposits, their growth is calculated separately using the future value of an annuity and added to the total.
Why compounding frequency matters
More frequent compounding (daily vs. annually) results in slightly higher returns because interest starts earning its own interest sooner. The effect is usually small for typical savings rates but can add up over long periods. Compare this with simple, non-compounding growth using our Interest Calculator.