Simple Interest Calculator
Calculate simple interest and total repayment amount for any principal, rate, and time period, instantly in your browser.
How to use the Simple Interest Calculator
- Enter the principal amount.
- Enter the annual interest rate as a percentage.
- Enter the time period in years.
- Click Run to see the simple interest and the total amount (principal plus interest).
How the Simple Interest Calculator works
Simple interest is charged only on the original principal, never on interest already earned:
Interest = P × r × t ÷ 100Total amount = P + Interest
For example, 5,000 at 6% for 3 years earns 900 in interest, for a total of 5,900. Because interest doesn't compound, simple interest grows in a straight line, while compound interest grows faster over time. Simple interest is common for short-term personal loans, car loans in some countries and certain bonds.
Frequently asked questions
- Is this simple interest calculator free?
- Yes. Calculate simple interest at no cost, with no account required.
- What is the simple interest formula?
- Simple interest = P x r x t / 100, where P is principal, r is annual interest rate, and t is time in years.
- How is simple interest different from compound interest?
- Simple interest is calculated only on the original principal, while compound interest is calculated on the principal plus accumulated interest.