Compound Interest Calculator

Calculate compound interest with different compounding frequencies. See total amount, interest earned, and growth over time.

Last updated: June 1, 2026

Principal Amount

Annual Rate (%)

Time (years)

Compounded

Total Amount

$20,096.61

Total Interest

$10,096.61

Principal

$10,000.00

What is Compound Interest Calculator?

A compound interest calculator shows how money grows over time when interest is earned not only on the original principal but also on previously accumulated interest. This 'interest on interest' effect is the fundamental principle behind investing, savings accounts, and long-term wealth building. Albert Einstein reportedly called compound interest the 'eighth wonder of the world.' This tool calculates your total returns, shows year-by-year growth breakdowns, and lets you compare different rates, time periods, and compounding frequencies to make informed financial decisions.

How It Works

The tool uses the compound interest formula: A = P(1 + r/n)^(nt), where P is the principal, r is the annual interest rate, n is the compounding frequency (daily, monthly, quarterly, annually), and t is time in years. For investments with regular contributions, it adds periodic deposits using the future value of annuity formula. The calculator shows a year-by-year breakdown so you can see how growth accelerates over time — the longer your money compounds, the more dramatic the growth curve becomes. All calculations are instant and update as you adjust any parameter.

Common Use Cases

•Planning retirement savings by seeing how monthly investments grow over 20-30 years
•Comparing savings accounts with different interest rates and compounding frequencies
•Understanding the long-term cost of debt by seeing how interest accumulates on loans
•Setting realistic investment goals by calculating required monthly deposits for a target amount
•Demonstrating the time value of money for financial education and planning discussions
•Comparing investment scenarios — lump sum vs systematic investment over the same period