Simple Interest Calculator
Calculate simple interest on any principal using SI = P × R × T / 100. Enter principal, rate and time to get the interest amount and total.
What Does This Tool Do?
Calculate simple interest using SI = P × R × T / 100. Enter the principal, annual rate and time period to get the interest amount and final total.
Key Features
SI = PRT/100
Standard simple interest formula.
Total Amount
Principal plus interest shown together.
Formula
Substituted calculation displayed.
Instant
Result immediately.
How to Use
- Enter the principal (the starting amount).
- Enter the annual interest rate as a percentage.
- Enter the time period in years.
- Click Calculate Simple Interest.
Frequently Asked Questions
What is simple interest?▾
Interest calculated only on the original principal — not on accumulated interest. Formula: SI = P × R × T / 100.
How is this different from compound interest?▾
Simple interest charges the same amount each period. Compound interest charges interest on the growing total, so it grows faster over time.
Can I enter time in months?▾
Yes — enter months/12 as a decimal. For 6 months enter 0.5, for 18 months enter 1.5.