Simple Interest Calculator

Calculate simple interest on a principal for any rate and period, and see how it compares with compound interest over the same term.

₹1,000₹1,00,00,000
%
0.5%30%
yr
0.5 yr30 yr

Simple Interest

₹40,000

on ₹1,00,000 at 8% for 5 years

Total amount (P + SI)

₹1,40,000

Compound interest, same inputs (annual)

₹46,933

Pin this scenario, change the inputs, and compare side by side.

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Tools that naturally follow this calculation.

Simple vs compound growth

  • Compound (annual)
  • Simple interest
12345₹0₹40 K₹80 K₹1.2 L₹1.6 L

Year-by-year

YearSimple InterestTotal
1₹8,000₹1,08,000
2₹16,000₹1,16,000
3₹24,000₹1,24,000
4₹32,000₹1,32,000
5₹40,000₹1,40,000

Example calculation

₹1,00,000 × 8% × 5 years ÷ 100 = ₹40,000 of simple interest, so the total becomes ₹1,40,000. With annual compounding instead, the interest over the same period would be about ₹46,933.

Simple interest formula

SI = P × R × T / 100

where P is the principal, R the annual interest rate in percent and T the time in years. The total amount is P + SI.

Where simple interest is used

Simple interest appears in short-term loans, some deposit products, informal lending, and as a teaching baseline. Most bank deposits and loans in India actually compound, so always check which method a product uses.

Simple vs compound interest

Simple interest is charged only on the original principal, so it grows in a straight line. Compound interest also earns interest on past interest, so the gap between the two widens every year — the comparison figure above shows this for your inputs.

Assumptions & Limitations

  • Interest is calculated only on the original principal.
  • The rate stays constant for the whole period.
  • Fractional years are allowed and pro-rated linearly.

Frequently asked questions

Please note: Returns and values shown are illustrations based on the assumptions you select and are not guaranteed. This tool is for education only and is not investment, tax, or financial advice.

Methodology last reviewed: 1 June 2026