Simple Interest Calculator
Calculate simple interest quickly using principal amount, annual interest rate, and time period. This free calculator helps estimate total interest earned or owed and the final amount after interest.
Calculate Simple Interest
Enter the details below to calculate the simple interest on your investment.
How to Use the Simple Interest Calculator
- Enter principal amount: Type the starting amount of money you invested or borrowed.
- Add annual interest rate: Enter the yearly interest rate as a percentage, such as 5 for 5%.
- Set time period: Provide a time value and choose years or months.
- Read the results: View the total simple interest and final amount (principal plus interest).
Simple Interest Formula
Interest = Principal × (Rate ÷ 100) × Time
Total Amount = Principal + Interest
Frequently Asked Questions
What formula does this calculator use?
It uses the simple interest formula: Interest = Principal × Rate × Time, where rate is annual and time is converted to years when needed.
Does this tool calculate compound interest?
No. This specific tool calculates simple interest only. Use a compound interest calculator when interest is reinvested over multiple periods.
Can I enter time in months?
Yes. Select months and the calculator automatically converts the value to years for the simple interest formula.
Is this interest calculator free?
Yes. It is free to use and works directly in your browser on desktop and mobile.