Compound Interest Calculator
See how money grows when interest earns interest — with optional monthly deposits.
%
—Final balance
—Total interest earned
—Total contributions
—Effective annual rate
—Doubling time (rule of 72)
Year by year
| Year | Contributions | Interest | Balance |
|---|
● Calculations run in your browser. Your numbers are never sent anywhere.
How it works
With compounding, interest is added to the balance and then earns interest itself: A = P(1 + r/n)nt, where n is the number of compounding periods per year (continuous compounding uses Pert). Monthly contributions are added at the end of each month and grow from then on. The effective annual rate shows the real yearly growth after compounding.