Compound Interest Calculator

Enter a starting amount, interest rate and number of years, choose how often interest compounds and add a monthly contribution if you like. You get the future value, total interest, effective annual rate and a year-by-year table that you can download as CSV.

How to use the Compound Interest Calculator

1. Enter the initial principal and the annual interest rate.
2. Enter the number of years and the compounding frequency.
3. Optionally add a monthly contribution.
4. Press Calculate and download the yearly table if needed.

Features

• Annual, semi-annual, quarterly, monthly, daily or continuous compounding
• Monthly contributions added at the end of each month
• Effective annual rate (APY) for the chosen compounding
• Year-by-year table with CSV export

Benefits

• Understand how time and regular saving multiply growth
• Compare savings accounts quoted with different compounding

Frequently asked questions

What formula is used?

Without contributions, A = P(1 + r/n)^(nt). Contributions are simulated month by month using the equivalent monthly rate for your compounding frequency.

What is the difference between APR and APY?

The nominal rate (APR) ignores compounding; APY includes it. 6% compounded monthly is an APY of about 6.17%.

Are taxes and inflation included?

No. The calculation assumes a constant rate with no taxes, fees or inflation. Results are estimates for planning and education, not financial advice.

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