Simple Interest Calculator
A free, browser-based calculator. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserBasic
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter the principal, the annual rate and the number of years.
- Press Calculate.
How it works
Simple interest is charged only on the original principal: Interest = P × r × t ÷ 100. Unlike compound interest, it doesn't earn interest on interest.
Worked example
$1,000 at 5% for 2 years. Interest = 1,000 × 5 × 2 ÷ 100 = $100, so $1,100 in total.
Frequently asked questions
When is simple interest used?
Some short-term loans and bonds. Most savings accounts and mortgages use compound interest.
Related tools
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.