Simple interest calculator
Calculate interest without compounding.
Interest is calculated on the starting principal only. Fees, taxes, payment schedules and changing rates are excluded. For interest earned on previous interest, use the Compound interest tool. Change the input or settings to update your result. Results update as you type. Up to 1,000,000 characters.
Your result
How to use Simple interest calculator
- Enter the values you want to calculate and choose the relevant units or settings.
- The result updates as you type. Adjust the available settings if needed.
- Review the result, then use Copy result or a download link when available.
Useful next steps
How to use it
Enter the principal, annual percentage rate and number of years. Simple interest is principal × rate × time, with the rate expressed as a decimal.
A worked example
A principal of 1,000 at 5% a year for 3 years earns 150 in simple interest. The final amount is 1,150.
What to know
Interest is calculated on the starting principal only. Fees, taxes, payment schedules and changing rates are excluded. For interest earned on previous interest, use the Compound interest tool.