Simple Interest Calculator
Calculate simple interest and total amount based on principal, annual rate and time period using the SI = P × R × T / 100 formula.
✓ Runs in your browser · Updated 2026-03-31Enter values and click Calculate Interest to see results
How to Use the Simple Interest Calculator
Enter the principal amount, the annual interest rate and the time period in years. Click Calculate to instantly see the simple interest and total amount you will receive.
What Is Simple Interest?
Simple Interest (SI) is interest calculated only on the original principal amount. Unlike compound interest, the interest does not earn further interest. It is commonly used for short-term loans, car loans, and some savings instruments.
Simple Interest Formula
SI = P × R × T / 100
- P — Principal (initial amount)
- R — Annual rate of interest (%)
- T — Time period in years
Total Amount = P + SI
Simple Interest vs Compound Interest
With simple interest, a ₹1,00,000 deposit at 8% for 5 years earns ₹40,000 interest. With compound interest (yearly), the same deposit earns ₹46,933 — that's ₹6,933 more due to interest-on-interest. For long-term investments, compounding makes a dramatic difference.
Where Is Simple Interest Used?
- Short-term personal loans and car loans.
- Some government bonds and treasury bills.
- Flat-rate EMI calculations (though reducing balance is more common — see our EMI Calculator).
- Academic and school-level math problems.
Frequently Asked Questions
What is the formula for simple interest?
Simple Interest = (P × R × T) / 100, where P is the principal amount, R is the annual interest rate, and T is the time in years.