Compound Interest Calculator
Free online Compound Interest Calculator.
Calculator
How to Use
- Enter the required values
- Click Calculate to see the result
- Review the detailed output
Formula
A = P(1 + r/n)^(nt), where A = final amount, P = principal, r = annual interest rate (decimal), n = compounding frequency per year, t = time in years.
Example Calculations
Long-Term Savings
Input: $10,000 at 7% compounded monthly for 20 years
Result: Final: $40,387.39, Interest earned: $30,387.39
With Monthly Contributions
Input: $5,000 at 6%, $200/month for 10 years
Result: Final: $39,064.28, Total contributed: $29,000
Annual Compounding
Input: $25,000 at 5% compounded annually for 15 years
Result: Final: $51,968.53, Interest earned: $26,968.53
About This Calculator
Free online compound interest calculator. Calculate instantly in your browser with our easy-to-use tool. No sign-up required.
Our compound interest calculator is free, easy to use, and provides instant results. All calculations are performed in your browser for privacy and speed.
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Frequently Asked Questions
What is compound interest?
Interest on both principal and accumulated interest. Formula: A = P(1 + r/n)^(nt).
How does compounding frequency help?
More frequent compounding generates slightly higher returns. The difference grows over long periods.
What is the rule of 72?
Divide 72 by the annual rate to estimate doubling time. At 8%, money doubles in about 9 years.
Compound vs simple interest?
Simple is on principal only. Compound includes accumulated interest, growing significantly faster.
Can compound interest hurt me?
Yes, with debt. Credit cards accumulate interest on both original and unpaid interest, causing rapid growth.
What is continuous compounding?
Interest at every instant: A = Pe^(rt). Maximum possible return for a given rate.