EMI Formula Explained (With Worked Examples)

EMI (Equated Monthly Instalment) isn't simply the loan amount split evenly across the number of months. It's calculated so that each instalment is identical in size, even though the mix of interest and principal inside each one changes every month. Here's the actual formula, and what it looks like with real numbers.

The formula

EMI is calculated as:

EMI = [P x R x (1 + R)^N] / [(1 + R)^N - 1]

• P — principal (the loan amount)
• R — monthly interest rate (annual rate ÷ 12 ÷ 100)
• N — number of monthly instalments (loan tenure in months)

Worked example: a car loan

Say you borrow ₹6,00,000 at 9% annual interest for 5 years (60 months).

• P = 600,000
• R = 9 ÷ 12 ÷ 100 = 0.0075
• N = 60

Plugging into the formula gives an EMI of roughly ₹12,451 per month — for a total repayment of about ₹7,47,060, meaning around ₹1,47,060 is interest over the life of the loan.

Worked example: a home loan

A larger, longer loan changes the shape of the numbers a lot. Borrow ₹40,00,000 at 8.5% for 20 years (240 months):

• P = 4,000,000
• R = 8.5 ÷ 12 ÷ 100 ≈ 0.00708
• N = 240

This works out to an EMI of roughly ₹34,700 per month — but because the tenure is so much longer, total interest paid over 20 years comes to well over the original principal, even though the annual rate is lower than the car loan example above.

Why interest is "front-loaded"

Each EMI is the same amount, but the split between interest and principal isn't. Early instalments are mostly interest (since the outstanding principal is still large); later instalments are mostly principal. This is why paying off a loan a few years early saves more interest than the simple "years remaining ÷ total years" math would suggest — you're skipping instalments that were still interest-heavy.

What changes the EMI most

Of the three inputs, tenure has the most counterintuitive effect: stretching a loan from 5 to 10 years roughly halves the EMI, but can nearly double total interest paid, since you're paying interest on the outstanding balance for twice as long.

Rather than working through the formula by hand for every scenario, our EMI Calculator gives you the monthly instalment and the full interest-vs-principal breakdown instantly. If you're instead trying to work backward from an EMI you can afford, the Loan Calculator tells you the maximum loan amount that fits.