Compound Interest Calculator

Compound interest shows how money grows when interest earns interest over time. This calculator estimates the future value of an initial amount plus regular contributions. It is useful for long-term planning, savings goals, and understanding how time and rate changes affect growth.

The key drivers are the interest rate, the number of years, and the contribution amount. Even a small change in rate or time can have a large effect. By testing multiple scenarios, you can see which levers matter most for your goals.

The calculator assumes a constant annual rate and consistent contributions. Real-world returns can fluctuate, and contributions may vary. The output is an estimate designed to help you think through a plan, not a guaranteed outcome.

You can use the tool to compare scenarios such as: saving $200 per month for 20 years versus saving $300 per month for 15 years, or comparing 5% and 7% rates over a long horizon. These comparisons make the power of compounding more concrete.