Compound Interest Calculator

A compound interest calculator helps you determine how your money grows over time when interest is earned on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, which only earns interest on the original amount, compound interest accelerates your wealth growth exponentially.

This free online calculator instantly shows you the future value of your investment, total interest earned, and how different compounding frequencies affect your returns. Whether you're planning for retirement, saving for a goal, or comparing investment options, understanding compound interest is essential for making informed financial decisions.

Albert Einstein reportedly called compound interest "the eighth wonder of the world." The longer your money compounds, the more dramatic the growth becomes. Our calculator lets you experiment with different scenarios to see exactly how time, rate, and compounding frequency impact your wealth.

1. Enter your initial investment — The starting amount you plan to invest.
2. Set the annual interest rate — The expected yearly return percentage.
3. Choose the time period — How many years you plan to keep the investment.
4. Select compounding frequency — How often interest is calculated (monthly, quarterly, etc.).
5. View your results — See the future value, total interest, and share via URL.

The compound interest formula is:

A = P(1 + r/n)^(nt)

Where: A = future value, P = principal, r = annual rate (decimal), n = compounds per year, t = years.

Example: $10,000 at 5% compounded monthly for 10 years: $10,000 × (1 + 0.05/12)^(12×10) = $16,470.09