Simple Interest Calculator
Calculate simple interest, charged only on the original principal.
Interest on the principal alone
Simple interest is calculated only on the original amount, never on accumulated interest, so it grows in a straight line rather than accelerating. This works it out from the principal, rate and time — the model behind some short-term loans and straightforward interest arrangements.
Enter the principal, rate and time to see the interest.
Simple versus compound
The contrast with compound interest is the whole point. Simple interest adds the same amount each period, because it always applies to the original sum; compound interest applies to the ever-growing total, so it pulls ahead and the gap widens over time. Over a short period the two are close, but over years the difference becomes dramatic. Knowing which one applies matters: some loans and bonds use simple interest, while savings and most investments compound. When you are the borrower, simple interest is friendlier; when you are the saver, compound is what you want working for you.
Simple Interest Calculator FAQ
How is simple interest different from compound?
Simple interest applies only to the original principal, so it grows in a straight line; compound applies to the growing total, so it accelerates and pulls ahead over time.
Where is simple interest used?
Some short-term loans and bonds. Savings and most investments compound instead, which favours the saver.
Is anything uploaded?
No. The calculation happens in your browser.