How to Calculate EMI: Formula, Worked Example and 7 Ways to Pay Less Interest

An EMI (Equated Monthly Instalment) is the fixed amount you pay your lender every month until a loan is fully repaid. Each EMI has two parts: interest on the money you still owe, and a repayment of part of the loan itself. Knowing how it is worked out helps you compare loans properly instead of choosing the one with the lowest monthly figure.

You can follow along with our free EMI calculator, which shows the monthly EMI, total interest, total payment and a full month-by-month schedule. Everything runs in your browser, so the loan details you enter are not sent anywhere.

The EMI formula

The standard formula for a loan with a fixed interest rate is:

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, then by 100. A 10% yearly rate gives r = 10 ÷ 12 ÷ 100 = 0.008333.
• n is the number of monthly instalments. A 5-year loan has n = 60.

A worked example

Take a loan of ₹10,00,000 at 10% a year for 5 years.

1. Monthly rate: r = 10 ÷ 12 ÷ 100 = 0.008333
2. Number of instalments: n = 60
3. Put these in the formula and the EMI comes to about ₹21,247 a month.
4. Total paid over 60 months: about ₹12,74,823.
5. Total interest: about ₹2,74,823.

So borrowing ₹10 lakh for five years at 10% costs roughly ₹2.75 lakh extra. You can check these figures by entering the same numbers in the EMI calculator.

How the loan tenure changes your cost

The same loan costs very different amounts depending on how long you take to repay it. This table shows a ₹30,00,000 loan at 8.5% a year:

Stretching the loan from 15 to 25 years cuts the EMI by about ₹5,400 a month, but adds roughly ₹19 lakh in interest. A lower EMI feels comfortable, but the total cost is what matters over the long run.

Why the early EMIs are mostly interest

Interest is charged on the balance you still owe, and the balance is highest at the start. On the ₹30 lakh, 20-year loan above, the first month's interest is ₹30,00,000 × 8.5% ÷ 12 = ₹21,250. Your EMI is ₹26,035, so only about ₹4,785 goes towards the principal. Each month the balance falls slightly, so the interest share shrinks and the principal share grows. The amortisation schedule in the calculator shows this month by month.

7 ways to pay less interest

1. Choose the shortest tenure you can comfortably afford

A shorter tenure has a higher EMI but far less total interest. Pick the shortest tenure that still leaves room for your other expenses and an emergency fund.

2. Make a larger down payment

Every rupee you pay upfront is a rupee you do not borrow, and you save the interest on it for the whole tenure.

3. Prepay when you can

Extra payments reduce the outstanding balance, so future interest falls. In our calculator, adding just ₹3,000 a month to the ₹30 lakh, 8.5%, 20-year loan reduces the tenure from 240 to about 187 months and saves about ₹8.3 lakh in interest. Banks apply prepayments in different ways, so treat the saving as an estimate.

4. Compare the rate, not just the EMI

A difference of even half a percentage point adds up over 20 years. Compare offers from several lenders, and ask whether the rate is fixed or floating and how it is linked to a benchmark.

5. Round up your EMI

Paying a slightly higher fixed amount, such as rounding ₹26,035 up to ₹27,000, works like a small regular prepayment without much effort.

6. Watch the fees

Processing fees, documentation charges and insurance can add to the real cost. Ask for a written list of all charges and compare them across lenders.

7. Review the loan when rates change

If your rate is floating and market rates have fallen, ask your lender whether you can reduce your rate, or compare a transfer to another lender after counting any charges.

What an EMI calculator does not show

An EMI calculator works out principal and interest only. It does not include processing fees, insurance, late-payment charges or taxes on fees. If your interest rate is floating, your actual EMI or tenure may change over time. For many floating-rate loans to individuals, lenders are not allowed to charge a prepayment penalty, but the rules depend on the loan type, so read your loan agreement and the Reserve Bank of India's guidelines for borrowers.

Before you sign a loan

• Calculate the EMI and the total interest, not just the monthly figure.
• Check that the EMI is a comfortable share of your monthly income.
• Ask whether the rate is fixed or floating and what can change it.
• Ask about prepayment, part-payment and foreclosure rules.
• Get all fees and insurance charges in writing.

If you are also planning how to grow savings alongside a loan, try the SIP calculator, and use the interest calculator to compare simple and compound interest.