Compound Interest Calculator

The compound interest formula

Without contributions the balance is A = P × (1 + r/n)^(n×t), where P is the principal, r the annual rate, n the number of compounding periods per year and t the years. 10,000 at 5% compounded yearly for 10 years grows to 16,288.95.

Adding regular contributions

Each contribution is added at the end of its period and earns interest for the remaining time. Saving 200 a month on top of a 10,000 start makes a dramatic difference over a decade — the yearly table shows exactly how much came from deposits and how much from interest.

Compounding frequency matters

The more often interest is added, the more you earn. 1,000 at 12% for one year gives 1,120.00 compounded yearly and 1,126.83 compounded monthly.