📈 Compound Interest Calculator
Enter a starting amount, interest rate, and time period to see how compound interest grows your money — with an optional monthly contribution added in.
How the Compound Interest Calculator works
Interest is calculated on your growing balance at each compounding period, not just the original amount, so earnings themselves start earning too — this is what makes compound growth accelerate over time.
Step-by-step calculation
- 1Enter the starting amount.
- 2Enter the rate, compounding frequency and years.
- 3Interest is added to the balance each period.
- 4Read the final amount and total interest.
Worked example
$10,000 at 5% compounded monthly for 10 years grows to $16,470.09.
Compound Interest Calculator examples
| Starting amount ($) | Future value |
|---|---|
| 5,000 | ~$10,048 (estimate) |
| 7,500 | ~$15,072 (estimate) |
| 10,000 | ~$20,097 (estimate) |
| 12,500 | ~$25,121 (estimate) |
| 15,000 | ~$30,145 (estimate) |
Other inputs kept at the calculator's default values. Results calculated by this calculator.
Why use a Compound Interest Calculator?
See how savings and investments grow over time.
Important factors that can affect your results
- Compounding frequency.
- Taxes and fees reduce growth.
- Investment returns are not guaranteed.
Frequently asked questions
What does "compounding frequency" mean?
How often interest is calculated and added to your balance — annually, monthly, or daily. More frequent compounding grows your balance slightly faster.
Are monthly contributions included?
Yes — optionally add a fixed monthly contribution to see its combined effect alongside compound growth.
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Last reviewed November 2026 · How we build and check our tools · Report a problem