Interest Calculator
Calculate simple and compound interest on savings or investments. Adjust the rate, time, and compounding frequency to see how your money grows.
How to calculate interest
- Choose simple or compound interest.
- Enter the principal, annual rate, and time in years.
- For compound interest, pick how often it compounds (yearly, monthly, daily).
- See the interest earned and the final balance.
Simple vs. compound interest
Simple interest is calculated only on the original principal. Compound interest is calculated on the principal plus all previously earned interest, so it grows faster over time — the more frequently it compounds, the more you earn.
Frequently asked questions
What’s the difference between simple and compound interest?
Simple interest is earned only on your original deposit. Compound interest is earned on your deposit plus accumulated interest, so it grows faster.
How does compounding frequency affect returns?
More frequent compounding (e.g. monthly vs. yearly) produces slightly higher returns because interest is added to the balance more often.
Is my data uploaded?
No. Every calculation runs entirely in your browser.