Simple Interest Calculator
Compute simple interest, solve for any of the four variables, and compare against compound interest.
Interest
1 500,00 $US
Total amount
11 500,00 $US
Compound would be
1 576,25 $US
+76,25 $US vs simple
Interest 1 500,00 $US, total 11 500,00 $US
📐 About This Calculator
Simple interest is charged only on the original principal, so it grows in a straight line — unlike compound interest, which also earns on accumulated interest.
SI = P × R × T ÷ 100
Total = P + SI
4-WAY SOLVE:
P = SI × 100 ÷ (R × T)
R = SI × 100 ÷ (P × T)
T = SI × 100 ÷ (P × R)
Variable Definitions:
- • P = Principal
- • R = Annual rate (%)
- • T = Time in years
✅ Best used for:
- • Short-term loans
- • Fixed-interest deposits
- • Quick interest estimates
⚠️ Limitations:
- • Ignores compounding — understates long-term growth
- • Assumes a constant rate
📖 How Simple Interest is Calculated
Simple vs compound interest
Simple interest stays flat each year; compound interest accelerates because it also earns interest on prior interest. Over long periods the gap becomes large.
Solving for any variable
If you know any three of principal, rate, time and interest, the fourth follows directly from the formula.