Enter values and select Calculate to see your result.
Principal, Rate & Time
Simple interest is calculated only on the original principal amount.
View formula
Interest = Principal × Rate × Time
How to use the Simple Interest Calculator
Calculate interest only on original principal using an annual rate and time period.
- Enter principal, annual rate and years.
- Calculate interest and total amount.
- Compare with compound interest when interest is reinvested.
Simple Interest Calculator formula
Simple interest = principal × rate × time; total = principal + interest.
Worked example
Inputs: $10,000 at 6% for 3 years.
What to expect: Simple interest is $1,800 and total is $11,800.
How to read your result
Unlike compound interest, prior interest does not earn additional interest.
Frequently asked questions
Does it compound?
No. It applies the rate only to original principal.
What unit should time use?
Use years when the entered rate is annual.