Interest calculator

Calculate simple and compound interest on your investment with side-by-side comparison. Free in your browser with no signup.

Basic details

Advanced options

Final amount
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Total interest
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Principal
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Comparison: simple vs compound

Simple interest
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Compound interest
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How to use the interest calculator

  1. Choose simple or compound interest and investment type.
  2. Enter principal, rate, duration, and compounding frequency if needed.
  3. Click “Result” to see final amount, interest earned, and comparison.

Interest calculator — frequently asked questions

Yes. The tool is completely free and runs in your browser with no account required.

Simple is calculated on principal only. Compound adds interest to the balance periodically.

Yes. In compound mode you can enter an optional extra monthly deposit.

Yes. It shows a comparison between simple and compound results.

Yes. The tool is responsive and works on phones, tablets, and desktop browsers.