Simple Interest Calculator — Interest & Total Amount
Free simple interest calculator. Find the interest and total amount from principal, annual rate and time in years, months or days.
Runs in your browser — your data is never uploaded.
Simple interest is calculated only on the original principal. Enter the principal, rate per year and the time period (years, months or days) to find the interest earned and the total amount. It is useful for short-term loans, personal lending and quick school or exam questions.
How to use the Simple Interest Calculator
- Enter the principal and annual rate.
- Enter the time and choose the unit.
- Read the interest and total amount.
Simple Interest Calculator — frequently asked questions
What is the simple interest formula?
SI = P × R × T ÷ 100, with T in years.
How is it different from compound interest?
Simple interest never adds earned interest back to the principal.
How do I use months?
Choose months as the unit and the tool converts to years automatically.
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