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Compound Interest Calculator
Enter your numbers. Watch compound interest work in real time — results update as you type.
Calculate Compound Growth
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Final Balance—
Total Contributions—
Interest Earned—
Total Return—
Money Doubles Every—
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Year-by-Year Breakdown
| Year | Balance | Contributed | Interest |
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How Compound Interest Works
Compound interest means you earn interest on your interest — not just your original principal. The longer you invest, the more powerful this becomes. Albert Einstein reportedly called it "the eighth wonder of the world."
Rule of 72
Divide 72 by your annual return to find how long it takes to double your money. At 7% return: 72 ÷ 7 = 10.3 years to double. At 10%: just 7.2 years.