📈 Compound Interest Calculator
Watch your savings and investments grow over time
Investment Details
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Results
Future Value
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Total Contributions
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Interest Earned
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Interest %
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Year-by-Year Breakdown
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Frequently Asked Questions
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. This "interest on interest" effect causes investments to grow exponentially over time — the longer you invest, the more powerful the effect becomes.
The more frequently interest compounds, the more you earn. Daily compounding yields slightly more than monthly, which yields more than annual. For most savings accounts and investments, monthly compounding is most common. The difference between daily and monthly compounding is usually small.
The Rule of 72 is a quick way to estimate how long it takes to double your money. Divide 72 by your annual interest rate: at 8% per year, your money doubles in approximately 72 ÷ 8 = 9 years.