Free financial decision tools

The Power of Compound Interest

Watch your money grow exponentially. Adjust the inputs and see how time, contributions, and rate work together.

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Your Inputs
Starting point, contributions, and growth rate
Total Future Value
$0
$0
Total Contributed
$0
Interest Earned
0%
Interest as % of Total
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Growth Over Time
Contributions vs compound interest
Your Contributions
Interest Earned
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Year-by-Year Breakdown
Watch the compounding accelerate
YearContributionsInterest EarnedTotal Balance
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How Compound Interest Works

Compound interest means you earn returns not just on your original money, but also on the interest that's already accumulated. This creates a snowball effect — the longer your money compounds, the faster it grows. A 7% annual return doubles your money roughly every 10 years (the Rule of 72). This calculator compounds monthly, which is standard for most investment and savings accounts.