Compound Interest Calculator
Use this free calculator to see how your savings or investment grows over time with compound interest. Enter the principal amount, annual interest rate, and number of years.
How it works
Compound interest is calculated using the formula A = P × (1 + r)^t, where P is the principal amount, r is the annual interest rate (as a decimal), and t is the number of years. The interest earned is A minus P.
Frequently Asked Questions
What is compound interest?
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods, so your money grows faster than with simple interest.
Does a longer time period increase returns?
Yes — because interest compounds each year, a longer time horizon leads to significantly higher total returns for the same rate.