Interest Calculator
Calculate simple or compound interest on a principal amount.
Enter a principal, rate, and time period to see interest earned either way — useful for comparing a savings account's compound growth against a simple-interest loan or deposit.
Frequently asked questions
What's the difference between simple and compound interest?
Simple interest is calculated only on the original principal each period. Compound interest is calculated on the principal plus any interest already earned, so it grows faster over time.
Can I set how often interest compounds?
Yes — choose the compounding frequency (e.g. annually, monthly) along with the rate and time period.
What do I need to enter to calculate interest?
Principal amount, interest rate, and time period — the calculator returns the interest earned and the total amount.