Watch Your Money Grow with Compound Interest!
Put your savings to work with the power of compounding. Our Compound Interest Calculator helps you see how your investments grow over time with regular contributions and various compounding frequencies.
Put your savings to work with the power of compounding. Our Compound Interest Calculator helps you see how your investments grow over time with regular contributions and various compounding frequencies.
Compare long-term returns with our Rent vs Buy Calculator.
Our compound interest calculator shows how investments grow over time with compounding—earning interest on both principal and accumulated interest.
For a lump sum with no contributions:
A = P(1 + r/n)nt
Where P = principal, r = annual interest rate (decimal), n = compounding frequency per year, t = time in years.
For investments with periodic contributions, we use the future value of an annuity formula. The contribution portion grows as:
FVcontrib = PMT × [((1 + r/n)nt − 1) / (r/n)] × (n / contributions per year)
PMT = contribution amount. Total future value = principal growth + contribution growth. Total interest = final balance − principal − total contributions.
Small rate increases can significantly boost final balance due to exponential growth. Starting earlier—even with less—often outperforms starting later with more.