Simple Interest Calculator
Calculate simple interest earned on an original principal. Review the formula and assumptions before using the result.
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Formula
Simple interest I = principal × annual rate (%) × time in years ÷ 100. This calculator returns interest only, not principal plus interest.
Worked example
A principal of 1,000 at 5% per year for 3 years earns 150 in simple interest.
What the result means
Simple interest is calculated on the original principal each year; previously earned interest is not added to the base.
How to Use Simple Interest Calculator
Enter the requested values
Provide the inputs for this simple interest calculator. Use consistent units where applicable.
Read the simple interest
The result recalculates as you edit the inputs.
Check the simple interest calculator assumptions
Use the simple interest calculator formula and notes below to understand what is—and is not—included.
Key Features & Benefits
Formula and worked example
A principal of 1,000 at 5% per year for 3 years earns 150 in simple interest.
Clear scope
Simple interest is calculated on the original principal each year; previously earned interest is not added to the base.
Frequently Asked Questions
Does the result include the original principal?
No. The displayed result is interest only.
Is interest compounded?
No. Simple interest uses the original principal for the entire term.
Key terms
- simple interest calculator
- Simple interest is calculated on the original principal each year; previously earned interest is not added to the base.