Simple Interest Calculator

What is Simple Interest?

Simple Interest (SI) is the interest calculated only on the original principal amount for a given period of time. Unlike compound interest, simple interest does not take into account any interest that has already been earned. It is one of the most basic and widely used concepts in finance, commonly applied to short-term loans, fixed deposits, and savings instruments.

Simple Interest Formula

The formula for simple interest is: SI = (P × R × T) / 100, where P is the Principal amount, R is the Annual interest rate (in %), and T is the Time period in years. The total amount at maturity is calculated as A = P + SI.

How to Use This Calculator

1. Enter the principal amount (the initial sum of money).

2. Enter the annual interest rate as a percentage.

3. Enter the time period in years.

4. Click "Calculate Simple Interest" to see the interest earned, total amount, and principal.

Simple Interest vs Compound Interest

In simple interest, the interest is calculated only on the original principal throughout the entire period. In compound interest, the interest earned is added to the principal, and future interest is calculated on this new (larger) principal. Over longer periods, compound interest grows much faster than simple interest. Simple interest is typically used for short-term loans and deposits, while compound interest is used for savings accounts, mutual funds, and long-term investments.

Frequently Asked Questions

Where is simple interest used?

Simple interest is commonly used in personal loans, car loans, short-term fixed deposits, and government bonds. Banks in India often use simple interest for calculating interest on certain savings schemes and short-duration deposits.

Is simple interest better than compound interest?

For borrowers, simple interest is better because you pay less over time. For investors, compound interest is better because your money grows faster. The choice depends on whether you are lending or borrowing money.

Can the time period be in months?

This calculator uses years. To convert months to years, divide by 12. For example, 18 months = 1.5 years. Enter 1.5 in the time period field.