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Finance Calculators

Simple Interest Calculator

Verified formula Updated Jun 2026 Private — runs on your device

Enter details
₹
%
5 years
1 years50 years
Verified formula Private

Total interest

₹30,000

Principal
₹1,00,000
Total amount
₹1,30,000
View chart data
Total interest30000
Principal100000

For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.

How to use the Simple Interest Calculator

The Simple Interest Calculator works out your total interest, along with 2 related figures in an instant. Enter principal amount, interest rate (p.a.) and time period and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.

  1. Enter the principal amount.
  2. Enter the interest rate (p.a.).
  3. Set the time period.
  4. Read off your total interest, together with principal and total amount — the calculator updates automatically, with no button to press.

Formula

The Simple Interest Calculator uses the formula:

Total interest = Principal amount × Interest rate (p.a.) × Time period ÷ 100

Worked example

For example, with principal amount of ₹100,000, interest rate (p.a.) of 6% and time period of 5 years, the total interest is ₹30,000.

Inputs used
Principal amount ₹100,000
Interest rate (p.a.) 6%
Time period 5 years
Results
Total interest ₹30,000
Principal ₹1,00,000
Total amount ₹1,30,000

Results are estimates for educational use, not professional advice.

Key terms explained

Simple interest
Interest charged only on the original principal, calculated as principal × rate × time ÷ 100.
Interest rate
The percentage charged on a loan or paid on savings, usually quoted per year (per annum).
Principal
The original sum of money borrowed or invested, before any interest is added.

Frequently asked questions

Simple interest is interest calculated only on the original principal, not on accumulated interest. The formula is SI = P × R × T ÷ 100, where P is the principal, R the annual rate and T the time in years.

Simple interest is charged only on the principal, so it grows linearly. Compound interest is charged on the principal plus previously earned interest, so it grows faster over time.

It is common in short-term loans, car loans, some personal loans and fixed deposits quoted on a simple-interest basis. Always check whether a product uses simple or compound interest.

Yes. The calculation assumes a constant rate and ignores fees, taxes and any compounding. Use it as a quick estimate, not as financial advice.

The Simple Interest Calculator uses the formula: Total interest = Principal amount × Interest rate (p.a.) × Time period ÷ 100. For example, with principal amount of ₹100,000, interest rate (p.a.) of 6% and time period of 5 years, the total interest is ₹30,000.

Enter the principal amount. Enter the interest rate (p.a.). Set the time period. Read off your total interest, together with principal and total amount — the calculator updates automatically, with no button to press.

The Power of Compound Interest, Explained

Why compound interest is called the eighth wonder of the world — how it works, how it beats simple interest, how compounding frequency matters, and how long it takes to double your money.

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