Simple Interest Calculator

Calculate simple interest and total amount from principal, rate and time. Free online simple interest calculator with clear results.

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How to use the Simple Interest Calculator

Enter the principal amount.
Enter the annual interest rate and the time period.
Press Calculate to see simple interest and the total amount (principal + interest).
Reset to try different values.

How it works

Simple interest is Principal × Rate × Time (with rate as a decimal and time in years). Interest does not compound—each period uses the original principal only.

Often used for short-term loans, basic savings estimates and school math problems.

Examples

Principal 10,000, rate 5% per year, 2 years → interest = 1,000; total = 11,000.
Principal 5,000, rate 8%, 6 months (0.5 year) → interest = 200.
Doubling the time doubles the simple interest for the same principal and rate.

Simple Interest Calculator FAQ

What is the simple interest formula?

Interest = Principal × Rate × Time. Total amount = Principal + Interest.

How is this different from compound interest?

Simple interest does not earn interest on previous interest. Compound interest does.

Is the calculator free?

Yes. No sign-up required.