Compound Interest Calculator

How does compound interest grow your money?

Compound interest is interest earned on both your original deposit and on previously earned interest. Over time, this creates an exponential growth effect — your money earns money, and that money earns more money.

Why it matters: Starting early makes a huge difference. Someone who invests $200/month starting at 25 will have significantly more at 65 than someone who starts at 35 with the same contribution, even though they only contributed 10 years more.

The rule of 72: Divide 72 by your annual return rate to estimate how many years it takes to double your money. At 7% returns, your money doubles roughly every 10 years.