Simple Interest Calculator
Interest on principal only, no compounding.
Enter the values and press Calculate.
How to use Simple Interest Calculator
Simple interest is charged only on the original principal, not on accumulated interest. This tool multiplies principal, rate, and time.
Open Simple Interest Calculator on toolpermarket. It runs entirely in your browser, so you can start without creating an account.
Enter the principal, the annual rate, and the time in years in the fields above, then press Calculate.
Read the result below the form. Change any input and run it again as many times as you like — the math is instant and local.
Worked example. A $1000 loan at 5 percent for 3 years costs $150 in interest.
When to use Simple Interest Calculator. Use it for short-term loans, bonds, or any arrangement that does not compound.
Frequently asked questions
Is Simple Interest Calculator free to use?
Yes. Simple Interest Calculator runs entirely in your browser. There is no account, no upload, and no cost.
Does Simple Interest Calculator work on mobile?
Yes. The layout is responsive, so Simple Interest Calculator works on any phone, tablet, or desktop with a modern browser.
How is simple interest different from compound?
Simple interest ignores interest already earned. Compound interest adds it back, so it grows faster over time.
Can time be in months?
Enter time in years. For months, divide by 12 first, for example 6 months is 0.5 years.