Simple Interest Calculator
Calculate simple interest on loans or savings using principal, rate, and time.
Total Amount
11,500Interest Earned
1,500
Original Principal
10,000
Related Guide
Simple vs. Compound Interest: What's the Real Difference?
About This Tool
Free simple interest calculator — enter a principal amount, annual interest rate, and time period to instantly calculate the interest earned or owed and the final total amount. Unlike compound interest, simple interest is calculated only on the original principal for the entire term, which makes it common for short-term loans, certain bonds, and some auto loans. This tool shows the interest amount and the final total separately, and works for any time period expressed in years or months. Useful for comparing loan offers, estimating returns on simple-interest savings products, or checking a lender's math. Runs entirely in your browser — no data is ever sent anywhere.
How to Use
- 1
Enter the principal
Type the original loan or investment amount.
- 2
Enter rate and time
Add the annual interest rate and the time period in years.
- 3
See interest and total
View the interest earned or owed and the final total amount instantly.