Every time you take a loan — whether a home loan, car loan or personal loan — the bank tells you a single number: your EMI (Equated Monthly Instalment). But how is that number actually calculated? Understanding the EMI formula helps you plan your finances, compare loan offers, and spot when a lender is overcharging you.
What is EMI?
An EMI is the fixed amount you pay your lender every month until the loan is fully repaid. Each EMI has two parts: the principal (the actual money you borrowed) and the interest (the cost of borrowing). While the total EMI stays the same on a fixed-rate loan, the split shifts over time — early instalments are mostly interest, and later ones are mostly principal.
The EMI Formula
The standard EMI formula used by every bank in India is:
EMI = [P × R × (1+R)N] / [(1+R)N – 1]
Where:
- P = Principal (the loan amount)
- R = Monthly interest rate = (annual rate ÷ 12 ÷ 100)
- N = Loan tenure in months
How to Calculate EMI Manually — Step by Step
Let's calculate the EMI for a ₹30,00,000 home loan at 8.5% annual interest for 20 years.
Step 1 — Convert the annual rate to a monthly rate
R = 8.5 ÷ 12 ÷ 100 = 0.00708333
Step 2 — Convert tenure to months
N = 20 × 12 = 240 months
Step 3 — Calculate (1+R)N
(1.00708333)240 ≈ 5.4406
Step 4 — Plug into the formula
EMI = [30,00,000 × 0.00708333 × 5.4406] / [5.4406 – 1]
EMI = [1,15,615] / [4.4406] ≈ ₹26,035 per month
Over 240 months you pay ₹26,035 × 240 = ₹62.48 lakh, of which ₹30 lakh is principal and about ₹32.48 lakh is interest. That's why understanding EMI matters — you end up paying more than double the borrowed amount in interest over a long tenure.
EMI Examples for Different Loan Amounts
Here's how the EMI changes at 8.5% interest over 20 years:
| Loan Amount | Monthly EMI | Total Interest |
|---|---|---|
| ₹10 Lakh | ₹8,678 | ₹10.83 Lakh |
| ₹25 Lakh | ₹21,696 | ₹27.07 Lakh |
| ₹50 Lakh | ₹43,391 | ₹54.14 Lakh |
| ₹75 Lakh | ₹65,087 | ₹81.21 Lakh |
| ₹1 Crore | ₹86,782 | ₹1.08 Crore |
Skip the manual math — our free EMI Calculator does this instantly and shows a full year-by-year breakup. For specific loans, try the Home Loan EMI Calculator, Car Loan EMI Calculator or Personal Loan EMI Calculator.
How to Calculate EMI in Excel
If you prefer a spreadsheet, use the built-in PMT function:
=PMT(rate/12, tenure_in_months, -loan_amount)
For our example: =PMT(8.5%/12, 240, -3000000) returns ₹26,035. The loan amount is entered as a negative number because it's money going out.
What Affects Your EMI?
- Loan amount — a higher principal means a higher EMI.
- Interest rate — even a 0.5% difference adds lakhs over 20 years.
- Tenure — a longer tenure lowers the EMI but increases total interest paid.
Want a lower EMI? Read our guide on 7 proven ways to reduce your home loan EMI, or learn whether a fixed or floating interest rate suits you better.