Compound Interest Calculator
Calculate compound interest with different compounding frequencies, see your APY, and track year-by-year growth.
Understanding Compound Interest
Compound interest is calculated using the formula A = P × (1 + r/n)^(n×t), where P is the principal, r is the annual rate, n is the number of compounding periods per year, and t is the time in years. Unlike simple interest, compound interest earns returns on previously accumulated interest, creating exponential growth over time. The Annual Percentage Yield (APY) reflects the effective annual rate after compounding and is always higher than the stated rate when compounding is more than once per year.
To compare directly with non-compounding scenarios, see our Simple Interest Calculator. If you plan to make regular contributions on top of your initial deposit, the Investment Calculator models annual additions with compound growth.
The compounding frequency makes a meaningful difference: daily compounding yields slightly more than monthly, which yields more than quarterly, which beats annual. For most savings accounts and CDs, monthly compounding is standard. The year-by-year table above shows exactly how your balance grows each year so you can plan your financial goals with confidence.
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For a related calculation, use Simple Interest Calculator to calculate simple interest and compare it side-by-side with compound interest. Alternatively, use Interest Calculator to compute compound and simple interest for savings accounts and investments.
For the underlying method, read Compound Interest Calculator Guide: Compare Rates, Timing, and Compounding or Understanding Compound Interest: The Most Powerful Force in Finance.