💵 Simple Interest Calculator

Calculate simple interest on principal, rate, and time.

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What is a Simple Interest Calculator?

Simple interest is the most basic way of working out what you earn — or owe — on a sum of money, and it's still used in several Indian contexts: some Post Office schemes, short-term loans between individuals, and certain co-operative society deposits. Unlike compound interest, the interest here is calculated only on the original amount deposited or borrowed, never on interest already earned. This calculator gives you the exact interest amount and final maturity value for a given principal, rate, and time period.

Simple Interest Formula

Simple Interest = P × R × T ÷ 100

Where P is the principal, R is the annual interest rate (%), and T is the time in years. The total maturity amount is simply P plus the interest.

Worked Example

Suppose you deposit ₹50,000 at 8% per annum simple interest for 3 years.

Interest = 50,000 × 8 × 3 ÷ 100 = ₹12,000

At the end of 3 years, you'd have earned ₹12,000 in interest, giving a total maturity amount of ₹62,000. Notice the interest earned is identical every single year — ₹4,000 in year one, ₹4,000 in year two, ₹4,000 in year three — because it's always calculated on the original ₹50,000, not on the growing balance.

How to Use This Calculator

  1. Enter the Principal amount.
  2. Enter the Rate of interest per annum.
  3. Enter the Time period in years.
  4. Click Calculate to see the interest earned and total amount.
💡 Tip: If your bank or lender compounds interest quarterly or annually instead of applying simple interest, your actual returns (or dues) will end up higher than what this calculator shows — use the Compound Interest Calculator for those products instead.

To see how the same numbers change once interest starts compounding instead of staying flat, try the Compound Interest Calculator.

📅 Last reviewed: July 2026 · Formulas verified against RBI/SEBI/IT Dept guidelines.