Compound Interest Calculator
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multiply over time.
Enter your investment, rate, and time period. See exactly how compound interest grows your wealth.
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📅 Year-by-Year Growth
| Year | Balance | Contributed | Interest Earned |
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Compound interest facts
⏱Rule of 72. Divide 72 by your interest rate to find how many years it takes to double your money. At 7%, money doubles every ~10 years.
📅Starting 10 years earlier is more powerful than doubling your contributions. Time is the most valuable variable in compound interest.
💰S&P 500 historical average: ~10% annually before inflation, ~7% after. Not guaranteed, but a useful benchmark for long-term planning.
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