Calculate Simple Interest or Compound Interest on any principal amount. Compare both side-by-side.
| Principal (P) | — |
| Annual Rate (R) | — |
| Time (T) | — |
| Simple Interest (I) | — |
| Total Amount (P + I) | — |
I = P × R × T / 100 — Interest is calculated only on the original principal. Best for short-term loans and savings accounts. Example: ₹1,00,000 at 8% for 3 years → Interest = ₹24,000.
A = P × (1 + r/n)^(n×t) — Interest is calculated on principal plus accumulated interest each period. This is how fixed deposits, mutual funds, and long-term investments grow. Monthly compounding gives slightly more than annual.
For the same principal, rate, and time — compound interest always gives a higher amount than simple interest. The difference becomes dramatic over long periods: ₹1,00,000 at 8% for 20 years gives ₹2,60,000 (SI) vs ₹4,92,680 (CI monthly). That's ₹2.3 lakh extra!
Simple interest is used in short-term personal loans, auto loans (in some countries), treasury bills, and some fixed deposits. In India, most bank FDs and recurring deposits use compound interest.
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