About the Compound Interest Calculator

Compound interest means you earn interest on your interest as well as on your original deposit. Over many years this snowball effect can make a large difference, which is why starting early matters.

This calculator shows the final balance, the total interest earned and a year-by-year table. You can choose how often interest is added, from yearly to daily.

How to use the Compound Interest Calculator

Enter the starting amount (the principal).
Enter the yearly interest rate and the number of years.
Choose how often interest is compounded.
Press Calculate growth to see the final balance and the yearly table.

How it works

The final amount is A = P × (1 + r ÷ n)^(n × t), where P is the principal, r is the yearly rate as a decimal, n is the number of times interest is added each year and t is the number of years. The effective annual yield is (1 + r ÷ n)^n − 1, which shows the true yearly growth after compounding.

The result does not include taxes, fees or inflation, all of which reduce what your money can actually buy.

Frequently asked questions

What difference does compounding frequency make?

More frequent compounding gives slightly higher growth. For example, 10 percent compounded monthly yields a little more than 10 percent compounded yearly.

What is the rule of 72?

It is a shortcut for estimating doubling time. Divide 72 by the yearly rate. At 6 percent, money roughly doubles in 12 years.

Does this include regular deposits?

No. This calculator shows growth of a single starting amount. Regular deposits would increase the result further.