Compound Interest Calculator

Compound interest is the interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, which only earns interest on the principal, compound interest allows your money to grow exponentially over time. The more frequently interest compounds (daily, monthly, annually), the faster your investment grows.

Enter your initial investment amount (principal), the annual interest rate, the compounding frequency (daily, monthly, quarterly, or annually), and the investment period in years. The calculator will show you the final amount, total interest earned, and a year-by-year breakdown of your investment growth.

APR (Annual Percentage Rate) is the simple interest rate without compounding, while APY (Annual Percentage Yield) includes the effect of compound interest. APY is always equal to or higher than APR because it accounts for interest-on-interest. When comparing savings accounts, APY gives you the true return.

More frequent compounding leads to higher returns. Daily compounding yields slightly more than monthly, which yields more than annually. However, the difference becomes smaller as you increase frequency. The Rule of 72 is a quick way to estimate doubling time: divide 72 by your interest rate.

Yes, this calculator runs entirely in your browser. No financial data is sent to any server or stored anywhere. All calculations happen locally on your device, ensuring complete privacy for your financial planning.