Simple Interest Calculator
Calculate interest earned or owed when interest is not compounded (simple interest).
| Principal amount | |
| Annual interest rate | % |
| Time |
Result
Your result will appear here.
Formula
Simple Interest = Principal × Rate × Time
Total = Principal + Interest
How it works
Simple interest is calculated only on the original principal, not on accumulated interest.
Formula
- I = P × r × t, A = P + I (P principal, r annual rate as a decimal, t years).
Worked example
$2,000 at 4% for 3 years: interest = $240, total = $2,240.
This is an estimate for general information only.
How to use the Simple Interest Calculator
It takes a few seconds, and every figure is calculated in your browser.
- Enter the principal amount.
- Enter the annual interest rate.
- Enter the time.
- Press Calculate — the result appears in the dark panel beside the form.
- Use Copy, CSV, Share or Print under the result if you want to keep it.
Simple Interest Calculator — frequently asked questions
What formula does the Simple Interest Calculator use?
Simple Interest = Principal × Rate × Time Total = Principal + Interest
How does the Simple Interest Calculator work?
Simple interest is calculated only on the original principal, not on accumulated interest.
Can you walk through a worked example?
$2,000 at 4% for 3 years: interest = $240, total = $2,240.
Last updated 10 November 2026 · Formula, worked example and assumptions are documented above, and every result is calculated in your browser.