Compound Interest Calculator
See how money grows over time when interest earns interest. Enter your starting principal, an optional regular monthly contribution, the annual interest rate, how often interest compounds, and the number of years. The calculator applies the compound interest formula to the principal and the future-value-of-an-annuity formula to your contributions, giving an accurate final balance. It also splits the result into how much you put in versus how much interest you earned, which is the number that shows the real power of compounding over long periods. Changing the rate or the time horizon makes it clear why starting early matters so much. This is an estimate that ignores taxes and inflation, and it all runs locally in your browser.
How to use Compound Interest Calculator
- Enter your starting principal.
- Set the annual rate and compounding frequency.
- Add any regular contribution and the time period.
- Read the future value and interest earned.
Frequently asked questions
How does compounding frequency change the result?
More frequent compounding, such as monthly versus annually, means interest earns interest sooner, so the final balance is slightly higher for the same rate.
Can I include regular contributions?
Yes. You can add recurring deposits and the calculator grows both your starting balance and each contribution over time.
What does "interest earned" mean in the result?
It is the final balance minus everything you put in, showing the growth purely from compounding.
What is Compound Interest Calculator?
See how money grows over time when interest earns interest. Enter your starting principal, an optional regular monthly contribution, the annual interest rate, how often interest compounds, and the number of years.
Is Compound Interest Calculator free to use?
Yes. Compound Interest Calculator is completely free, with no sign-up and no usage limits.
Does Compound Interest Calculator work in a web browser?
Yes. Compound Interest Calculator runs in any modern web browser. There is nothing to download or install.
Is my data private with Compound Interest Calculator?
Yes. Compound Interest Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
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