Find out how much your money can grow with the power of compound interest. Enter your starting balance, interest rate, and how often it compounds.
Compound interest is interest calculated on both your original balance and on the interest that balance has already earned. Because each round of interest adds to the amount that future interest is calculated on, growth accelerates the longer money is left invested.
The more frequently interest compounds — daily rather than annually, for example — the faster a balance grows, though the difference between frequencies is usually small compared to the effect of interest rate and time.
This calculator also lets you add a fixed monthly deposit, so you can see how regular contributions combine with compounding to build savings over time.
A = P(1 + r/n)^(nt), where P is principal, r is annual interest rate, n is compounding frequency per year, and t is time in years.
Simple interest is calculated only on the original principal; compound interest is calculated on the principal plus previously earned interest, so growth accelerates over time.
Yes, especially over long time periods — daily or monthly compounding yields more than annual compounding at the same nominal rate, though the difference is usually modest compared to the rate itself.