Simple Interest Calculator
Enter the principal, annual rate and time in years to get the interest amount and the total payable — with the formula shown.
Simple interest is charged only on the original principal, never on accumulated interest, which makes it common for short-term loans and basic savings. This free calculator applies the classic formula — principal times rate times time divided by one hundred — and shows both the interest amount and the total you will pay or receive, with every step visible.
Enter the principal, annual rate and time in years, then press Calculate Interest.
How to use the Simple Interest Calculator
- Enter the principal amount — the sum borrowed or invested.
- Enter the annual interest rate and the time period in years.
- Press Calculate Interest to see the interest amount and the total, with the formula shown.
Simple Interest Calculator — FAQs
Is this simple interest calculator free?
Yes, completely free with no signup and no limits. Run as many calculations as you need for loans, lending or study, and everything is computed privately in your own browser, with no data ever leaving your device.
What is the simple interest formula?
Simple interest equals principal multiplied by rate multiplied by time, divided by 100. For example, Rs 50,000 at 10 percent for 3 years gives Rs 15,000 interest, making Rs 65,000 in total. The calculator shows this exact working under every result.
When is simple interest used instead of compound interest?
Simple interest is common for short-term personal loans, car financing with flat rates, and basic savings products. Compound interest, where interest itself earns interest, is standard for long-term investments and credit cards, and it always costs the borrower more over time.
Is any of my information stored or sent anywhere?
No. The calculator runs entirely in your web browser using JavaScript on your device. Your figures are never uploaded to a server, saved in a database or shared with anyone, and nothing is written to disk.