How is EMI Calculated? Complete Formula Explained

Published March 11, 2026 · 8 min read

If you've ever taken a loan or considered taking one, you've come across the term EMI. But how exactly is that monthly payment number calculated? In this guide, we break down the EMI formula step by step so you can understand exactly what goes into your monthly loan payment.

What is EMI?

EMI stands for Equated Monthly Installment. It is the fixed amount you pay to your lender every month until your loan is fully repaid. Each EMI payment has two components:

• Principal component: The portion that reduces your outstanding loan balance
• Interest component: The cost of borrowing, calculated on the remaining balance

In the early months, a larger portion of your EMI goes toward interest. As the outstanding balance decreases over time, the interest portion shrinks and the principal portion grows. By the end of the loan, almost your entire EMI goes toward principal repayment.

The EMI Formula

For a reducing balance loan (used by all major banks), EMI is calculated using this formula:

Where:

• P = Principal loan amount (the total amount you borrow)
• R = Monthly interest rate = Annual interest rate ÷ 12 ÷ 100
• N = Total number of monthly installments (loan tenure in months)

Step-by-Step Calculation Example

Let's calculate the EMI for a personal loan with these details:

• Loan Amount (P) = ₹5,00,000
• Annual Interest Rate = 12%
• Loan Tenure = 3 years (36 months)

Step 1: Convert annual rate to monthly rate

Step 2: Calculate (1+R)^N

Step 3: Apply the formula

Step 4: Calculate totals

• Total Payment = ₹16,607 × 36 = ₹5,97,852
• Total Interest = ₹5,97,852 − ₹5,00,000 = ₹97,852

How the EMI Components Change Over Time

Here's how the first few and last few EMIs break down for our example loan:

Month	EMI	Principal	Interest	Balance
1	₹16,607	₹11,607	₹5,000	₹4,88,393
2	₹16,607	₹11,723	₹4,884	₹4,76,670
3	₹16,607	₹11,840	₹4,767	₹4,64,830
... (months 4-34) ...
35	₹16,607	₹16,279	₹328	₹16,444
36	₹16,607	₹16,444	₹163	₹0

Notice how in month 1, ₹5,000 goes to interest and ₹11,607 to principal. By month 36, only ₹163 goes to interest and ₹16,444 to principal.

How Each Factor Affects Your EMI

Factor	If It Increases	EMI Impact	Total Interest Impact
Loan Amount	Higher	Increases	Increases
Interest Rate	Higher	Increases	Increases significantly
Tenure	Longer	Decreases	Increases significantly

EMI Reducing Balance vs Flat Rate

There are two interest calculation methods lenders use:

• Reducing Balance (what this formula calculates): Interest is calculated on the outstanding balance each month. Used by all major banks. Results in lower total interest.
• Flat Rate: Interest is calculated on the original loan amount for the entire tenure. Used by some NBFCs and vehicle dealers. A flat rate of 10% is roughly equivalent to a reducing balance rate of 17-18%.

Always ask your lender which method they use and compare offers on an equivalent reducing balance basis.

Key Takeaways

• EMI is calculated using a mathematical formula that considers loan amount, interest rate, and tenure
• Each EMI contains both principal and interest components that change over time
• A shorter tenure increases EMI but dramatically reduces total interest paid
• Even a small difference in interest rate compounds into significant savings over long tenures
• Reducing balance method (used by banks) is more favorable than flat rate method