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Compound Interest Calculator
Compound interest is interest earned on interest — the reason small regular savings grow surprisingly fast over decades. Enter the starting amount, annual rate, time period and how often interest compounds, and see the final amount, total interest earned and a year-by-year growth table.
Use the tool
How to use the Compound Interest Calculator
- Enter the starting amount, annual rate, years and compounding frequency.
- Adjust any optional settings to match your page, business or campaign.
- Click the button to generate your result instantly — nothing is uploaded; the tool runs in your browser.
- Copy the result, or download it as a file where that option appears, and paste it into your site, document or campaign.
Frequently asked questions
What is the compound interest formula?
A = P(1 + r/n)^(nt), where P is the principal, r the annual rate, n the compounding frequency per year and t the years.
Does compounding frequency matter much?
Monthly beats yearly, but the difference is small next to rate and time. Time in the market matters far more than the compounding schedule.
Is tax included?
No. Tax on interest or investment gains depends on your country and situation — treat the result as growth before tax.
What about regular deposits?
This version compounds a single starting amount. For monthly savings, run it once per deposit year, or add deposits to the principal and re-run.