Interest Calculator
Compute simple interest earned or owed on a principal balance.
Advertisement
Simple Interest Calculator
Calculate simple interest earned or owed on a principal balance over time.
$
%
years
Total amount
Principal
Total interest
Enter your details and press Calculate to see an instant breakdown.
How the simple interest calculator works
Simple interest is calculated only on the original principal — it does not compound over time.
I = P × r × t
- I — interest earned or owed
- P — principal amount
- r — annual interest rate (as a decimal)
- t — time in years
Example: $5,000 at 6% simple interest for 3 years earns $900 in interest, for a total of $5,900.
Use it to: estimate returns on simple-interest instruments like certain bonds, certificates of deposit, or short-term notes.