Finance & Money
Simple Interest Calculator
Interest = Principal × Rate × Time — no compounding
Simple Interest
SI = Principal × Rate × Time
Result appears here
How it works
How it works
The formula
SI = P × R × T
SI = P × R × T
- PPrincipal (starting amount)
- RAnnual interest rate (as a decimal)
- TTime in years
Example
$1,000 at 5% for 3 years
SI = 1000 × 0.05 × 3 = $150
Total = $1,000 + $150 = $1,150
Simple vs Compound
Simple interest only charges interest on the original principal. Compound interest charges interest on both the principal and accumulated interest — so it grows faster over time.
→ Try Compound Interest CalculatorHow it works▾
How it works
The formula
SI = P × R × T
SI = P × R × T
- PPrincipal (starting amount)
- RAnnual interest rate (as a decimal)
- TTime in years
Example
$1,000 at 5% for 3 years
SI = 1000 × 0.05 × 3 = $150
Total = $1,000 + $150 = $1,150
Simple vs Compound
Simple interest only charges interest on the original principal. Compound interest charges interest on both the principal and accumulated interest — so it grows faster over time.
→ Try Compound Interest Calculator