By the Tooliday Team. Last updated 14 November 2026.
When a bank says your EMI is ₹20,758 a month, it feels like a fixed fact. It is actually the result of a short formula using three numbers: the amount you borrow, the interest rate and the number of months. Once you see how those three interact, loan offers become much easier to compare.
This guide explains the formula, works through a real example, and shows what actually moves your instalment up or down. You can check any figure with our EMI Calculator.
What EMI means
EMI stands for Equated Monthly Instalment. It is the fixed amount you pay every month until a loan is repaid. Each EMI has two parts: interest on the amount you still owe, and a repayment of part of the principal. The total stays the same, but the split changes every month.
The EMI formula
EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1)
- P is the loan amount (the principal).
- r is the monthly interest rate. Divide the yearly rate by 12 and then by 100. A 9% yearly rate becomes 0.09 ÷ 12 = 0.0075.
- n is the number of monthly instalments. A 5 year loan has 60.
A worked example
Suppose you borrow ₹10,00,000 at 9% a year for 5 years.
- P = 10,00,000
- r = 0.0075
- n = 60
Plug these in and the EMI comes to ₹20,758.36 a month. Over 60 months you pay ₹12,45,501.31 in total, so the interest cost is ₹2,45,501.31.
How the first months are split
In month one you owe the full ₹10,00,000. Interest for that month is 10,00,000 × 0.0075 = ₹7,500. The rest of the EMI, ₹13,258.36, reduces the principal. Your balance becomes ₹9,86,741.64.
In month two the interest is calculated on that smaller balance: ₹7,400.56. So slightly more of your EMI goes to principal (₹13,357.79). This is why early EMIs are interest-heavy and later ones are mostly principal. It is also why prepaying early saves the most interest.
How tenure changes the picture
Same loan, same rate, but 10 years instead of 5:
| 5 years | 10 years | |
|---|---|---|
| Monthly EMI | ₹20,758 | ₹12,668 |
| Total interest | ₹2,45,501 | ₹5,20,109 |
A longer tenure makes the EMI feel lighter but more than doubles the interest you pay. The right choice depends on your budget, but it helps to see both numbers before deciding.
Reducing balance and flat rate are not the same
Some lenders quote a flat rate, where interest is charged on the original amount for the whole term. With a flat 9% over 5 years, the interest would be ₹4,50,000, giving an EMI of about ₹24,167. A reducing-balance loan at the same stated 9% costs ₹20,758. Always ask whether a quoted rate is flat or reducing, and compare the total amount you will repay, not just the headline percentage.
What actually lowers your EMI
- A lower interest rate. Even half a percentage point matters on a large loan, so compare offers and check your credit score before applying.
- A bigger down payment. Borrowing less reduces everything.
- A longer tenure. This lowers the EMI but raises the total interest, as shown above.
- Part-prepayment. Paying extra towards the principal early reduces the interest. Check your loan terms first, because some loans charge a prepayment fee.
Things the formula does not include
The EMI covers principal and interest only. Processing fees, insurance, GST on fees and late-payment charges are separate. Floating-rate loans can also change when the lender’s benchmark rate changes, which alters your EMI or your tenure. Your loan agreement and the lender’s schedule are the final word.
Try it yourself
Enter your own amount, rate and tenure in the EMI Calculator to see the monthly instalment, total interest and total payment. It runs in your browser, so your figures stay with you.
This article is for general information and is not financial advice. Rates, fees and terms differ between lenders. Please confirm details with your lender or a qualified adviser.