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Finance CalculatorsPrivate by design

Compound Interest Calculator

Enter a starting amount, interest rate, time period, and compounding frequency to see how your money grows with compound interest.

How to use this tool

  1. 1Enter your initial investment (principal).
  2. 2Enter the annual interest rate, number of years, and compounding frequency.
  3. 3Optionally add a regular monthly contribution to see its effect.

Frequently asked questions

What's the difference between simple and compound interest?+

Simple interest is calculated only on the principal. Compound interest is calculated on the principal plus any interest already earned, so growth accelerates over time.

How does compounding frequency affect returns?+

More frequent compounding (daily or monthly vs. annually) produces slightly higher returns for the same nominal interest rate, since interest starts earning interest sooner.

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