Compound Interest Calculator

See how your investment grows over time with compound interest. Supports monthly contributions and different compounding frequencies.

Investment Details
Final Balance
Total Invested
Interest Earned
Total Gain

Frequently Asked Questions

What is compound interest?
Compound interest is interest calculated on both the initial principal and the accumulated interest. Unlike simple interest, it grows exponentially — your earnings generate their own earnings.
What is the Rule of 72?
Divide 72 by the annual interest rate to estimate how many years it takes to double your investment. At 7% rate: 72 ÷ 7 ≈ 10.3 years to double.
Why does compounding frequency matter?
More frequent compounding means interest is calculated and added more often, resulting in slightly higher returns. Daily compounding yields marginally more than annual compounding.