📈Simple Interest Calculator

Calculate simple interest on a loan or investment.

Principal ($)

Annual Rate (%)

Time (years)

About Simple Interest Calculator

Calculate simple interest earned or owed on a principal amount at a fixed annual rate over any time period. Shows total interest, final amount, and a year-by-year breakdown. Useful for short-term loans, bonds, and basic investment return estimates.

How to Use Simple Interest Calculator

1
Enter the principal
Input the starting loan or investment amount.
2
Set rate and time
Enter the annual interest rate (%) and the loan or investment duration in years.
3
View the results
See the interest amount, total value, and annual breakdown table.

Common Use Cases

Estimating interest on a short-term personal loan
Calculating returns on Treasury bills or short-term bonds
Teaching interest concepts in financial literacy courses
Comparing simple vs compound interest scenarios

Frequently Asked Questions

What is the simple interest formula?

Simple Interest = Principal × Rate × Time, where Rate is the annual interest rate as a decimal and Time is the number of years. The total amount is Principal + Simple Interest.

How does simple interest differ from compound interest?

In simple interest, interest is calculated only on the original principal. In compound interest, interest is calculated on the principal plus previously earned interest. Simple interest produces a lower return/cost over time for the same rate.