Simple Interest Calculator
Calculate simple interest, total amount, and monthly loan payments. Uses the formula SI = P × R × T / 100.
SI = P × R × T / 100
What is Simple Interest?
Simple interest is calculated only on the principal amount, not on accumulated interest. It is commonly used for short-term loans, car loans, and savings accounts.
Formula
Simple Interest (SI) = P × R × T / 100
Total Amount = P + SI
Monthly Payment = Total Amount ÷ (T × 12)
Where:
- P = Principal (initial amount)
- R = Annual interest rate (%)
- T = Time period (years)
How to use this tool
- Enter the Principal (P) — the initial loan or investment amount
- Enter the Annual Rate (R%) — the yearly interest rate
- Enter the Time (T years) — the loan or investment duration
- Click Calculate
Example use cases
- Car loan: $15,000 principal at 6% for 3 years → $2,700 interest, $17,700 total
- Savings: $5,000 deposited at 4% for 2 years → $400 interest earned
- Short-term loan: $1,000 at 10% for 6 months (0.5 years) → $50 interest