Compound Interest Calculator

See how compound interest grows your investments over time with monthly contributions.

Initial Investment ($)

Annual Interest Rate (%)

Monthly Contribution ($)

Years to Grow

Compound Frequency

Final Balance

Total Contributions

Interest Earned

Growth Over Time

The Power of Compound Interest

Compound interest is often called the "eighth wonder of the world" because of its ability to grow money exponentially over time. Unlike simple interest, compound interest earns interest on both the principal and the accumulated interest.

The Rule of 72: A quick way to estimate how long it takes to double your investment. Divide 72 by your annual interest rate. At 7.2%, your money doubles in about 10 years.

Starting Early Matters: Thanks to compound growth, starting to invest just a few years earlier can result in significantly more wealth over time. Even small monthly contributions add up substantially over decades.