How EMI Is Calculated: Formula, Examples and Tips

The EMI formula, step by step

EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1)

P = loan amount (principal)
r = monthly interest rate = annual rate ÷ 12 ÷ 100
n = tenure in months

Three things trip people up:

• r is monthly, not yearly. 8.5% a year becomes 8.5 ÷ 12 ÷ 100 = 0.0070833.
• n is in months. 20 years is 240 EMIs.
• At 0% interest, the formula doesn't apply. The EMI is simply P ÷ n, which is how no-cost EMI offers work on paper.

It's called "reducing balance" because each month's interest is charged only on what you still owe, not on the original loan.

Checking the EMI in Excel or Google Sheets

Spreadsheets have the same formula built in as PMT. For the home loan below, type:

=PMT(8.5%/12, 240, -5000000)

The result is 43,391.16. The loan amount is entered as a negative number because it's money you receive, and the EMI is money you pay out. Leave the minus sign off and you'll get the same figure with a minus in front.

Interest for any single month

You don't need the full formula to check one month. Interest for the month = balance at the start of the month × r. Whatever is left of the EMI after that interest reduces your balance. That simple step, repeated, is the whole amortisation schedule.

Worked example: ₹50 lakh home loan

Loan ₹50,00,000 at 8.5% a year for 20 years:

1. Monthly rate: r = 8.5 ÷ 12 ÷ 100 = 0.0070833
2. Months: n = 20 × 12 = 240
3. (1 + r)^240 = 1.0070833^240 = 5.4412
4. EMI = 50,00,000 × 0.0070833 × 5.4412 ÷ (5.4412 − 1) = ₹43,391

You repay more than twice what you borrowed. Interest alone is about 108% of the loan amount.

Worked example: ₹8 lakh car loan

Loan ₹8,00,000 at 9% a year for 5 years:

1. r = 9 ÷ 12 ÷ 100 = 0.0075
2. n = 60
3. (1.0075)^60 = 1.5657
4. EMI = 8,00,000 × 0.0075 × 1.5657 ÷ 0.5657 = ₹16,607

Total interest is ₹1,96,401, so you repay ₹9,96,401 in all. The shorter tenure keeps interest to about a quarter of the loan, even though the rate is higher than on the home loan.

EMIs on other common loans

Tip: All of these, plus the home and car loans, are presets in our EMI calculator. Pick one and you'll see the same figures, plus a full month-by-month schedule you can download as a CSV.

How interest and principal change over time

Each month, the bank first takes interest on the outstanding balance. The rest of your EMI reduces the principal. Here's the start and end of the ₹50 lakh home loan:

Month 1's interest is simply ₹50,00,000 × 0.0070833 = ₹35,417. That's nearly 82% of the EMI. The principal part doesn't overtake the interest part until month 143, almost 12 years in.

This is why closing a long home loan early saves so much, and why the balance seems to barely move in the first few years.

Effect of tenure and interest rate

Longer tenure: smaller EMI, much more interest

Same ₹50 lakh at 8.5%:

Going from 20 to 30 years lowers the EMI by ₹4,945 a month but adds over ₹34 lakh of interest. Going from 20 to 15 years costs ₹5,846 more a month and saves more than ₹15 lakh.

Higher rate: every 0.5% counts

Same ₹50 lakh over 20 years:

Each 0.5% step adds roughly ₹1,600 to the EMI and ₹3.8 lakh to total interest.

On a floating-rate loan, banks often keep your EMI the same when rates rise and stretch the tenure instead. At 9% rather than 8.5%, an EMI of ₹43,391 would take 268 months to clear the loan instead of 240. Check your loan statement after every rate change.

Prepayment: the biggest lever you control

A prepayment goes straight to principal, so every later month charges interest on a smaller balance.

Say you pay an extra ₹5,00,000 on the home loan after the 60th EMI and keep the EMI unchanged:

• The loan ends after 204 months instead of 240, three years early.
• Total interest falls from ₹54,13,879 to ₹43,44,726, a saving of ₹10,69,153.

Cut the tenure or cut the EMI?

After a prepayment, most lenders let you choose. In the same example, the balance after 60 EMIs is ₹44,06,359. Paying ₹5 lakh brings it down to ₹39,06,359.

• Keep the EMI, shorten the loan: interest saved is ₹10,69,153, as above.
• Keep the end date, lower the EMI: the EMI for the remaining 180 months drops to ₹38,467, which is ₹4,924 less. But interest saved is only about ₹3.86 lakh.

Cutting the tenure saves almost three times as much here. Lower the EMI only if your monthly budget really needs the room.

The earlier you prepay, the more you save, because more of the loan's interest is still ahead of you. Our loan prepayment calculator shows the saving for any amount and timing, with the EMI kept the same so the loan simply ends sooner.

Note: Some lenders charge a fee on prepayment, especially on fixed-rate loans or loans to businesses. Read your loan agreement or ask the lender before you prepay.

Processing fees and other costs

The EMI formula covers only principal and interest. The real cost of a loan also includes:

• Processing fee: often a percentage of the loan, charged once. At 1%, it's ₹50,000 on a ₹50 lakh loan, and GST is usually added on top. Our EMI calculator shows the fee separately and adds it to the total cost (excluding GST).
• Insurance bundled into the loan: if the premium is added to the loan amount, you pay interest on it too.
• Other charges: documentation, valuation or legal fees, and late-payment penalties.

Warning: Watch out for flat-rate quotes. A flat 9% on an ₹8 lakh, 5-year loan charges ₹3,60,000 interest and an EMI of ₹19,333. A reducing 9% gives an EMI of ₹16,607. The flat quote is about the same as paying 15.7% on a reducing balance.

Before you borrow

1. Check how much you can borrow. Lenders cap your total EMIs at a share of your income. Our loan eligibility calculator uses 50% by default, and you can change it.
2. Compare offers on total cost, not just the rate. Put two or three quotes side by side in the loan comparison tool, including their fees.
3. Choose the shortest tenure you can comfortably afford, and plan to prepay when you get a bonus.