Compound Interest Calculator

See what money grows to with compound interest and regular contributions.

Final balance

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You put in
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Interest earned
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How this was calculated
Runs in your browser. Nothing you type is sent anywhere.
About the Compound Interest Calculator
Compound Interest Calculator shows what savings or investments grow to when interest is added monthly and earns interest itself, with an optional monthly contribution added at the end of each month.
It separates what you put in from the interest earned, so you can see how much the compounding contributed.
How to use it
  1. Enter your starting amount.
  2. Enter a monthly contribution, or 0.
  3. Enter the yearly interest rate and the number of years.
  4. Read the final balance, what you put in and the interest earned.
Example
$5,000 plus $200 a month at 5% a year for 10 years grows to $39,291.50: $29,000.00 contributed and $10,291.50 interest.
Questions
How often is interest compounded?
Monthly: the yearly rate is divided by 12 and applied each month.
Is the return guaranteed?
No. Investments rise and fall. A steady rate is a planning estimate, not a promise.
Does it include tax or fees?
No. Tax on interest and account fees reduce real-world growth.