Simple Interest Calculator
Free online simple interest calculator. Enter principal, rate, and time to get the interest earned and the total amount using I = P × r × t.
About This Free Online Simple Interest Calculator
Our free online simple interest calculator works out the interest on a loan or deposit using the classic formula I = P × r × t, where P is the principal, r is the annual interest rate, and t is the time. Enter your principal, the yearly rate, and the time in years and months, and it shows the interest earned or owed plus the total amount (principal plus interest). Simple interest is calculated only on the original principal, not on accumulated interest, which makes it common for short-term loans and some savings products. It runs entirely in your browser with no signup.
Features of Our Simple Interest Calculator
- Interest and total from principal, rate, and time
- Uses the I = P × r × t formula
- Time in years and months
- Clear interest-versus-total breakdown
- Instant results as you type
- 100% free, no signup — runs in your browser
How to Use the Simple Interest Calculator
Using this tool is simple and requires no signup or registration. Follow these steps:
- Enter the principal amount.
- Enter the annual interest rate as a percentage.
- Enter the time in years and months.
- Read the interest and the total amount, then copy or download it.
Frequently Asked Questions About Simple Interest Calculator
What is the simple interest formula?
Simple interest is I = P × r × t, where P is the principal, r is the annual rate as a decimal, and t is the time in years. The total you repay or receive is P + I. This calculator handles the conversion for you.
How is simple interest different from compound interest?
Simple interest is calculated only on the original principal, so it grows in a straight line. Compound interest is calculated on the principal plus previously earned interest, so it grows faster. Use our compound interest calculator for that case.
When is simple interest used?
Simple interest is common for short-term and car loans, some personal loans, and certain savings or bonds. Many longer-term loans and investments use compound interest instead.
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