Home Loan EMI Formula: How to Calculate EMI (With a ₹25 Lakh Example)
Short answer: EMI = P × r × (1 + r)ⁿ ÷ [(1 + r)ⁿ − 1], where P is the loan amount, r is the monthly interest rate (yearly rate ÷ 12 ÷ 100) and n is the number of months. For a ₹25 lakh loan at 8.5% for 20 years, r = 0.007083 and n = 240, so the EMI is ₹21,696 a month. A loan quoted at a "flat" rate costs much more than the same rate on a reducing balance.
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 contains two parts: interest on the loan you still owe, and a repayment of some of the loan itself (the principal). The total stays the same, but the split changes every month.
The formula, step by step
EMI = P × r × (1 + r)n ÷ [(1 + r)n − 1]
- P = the loan amount: ₹25,00,000
- r = the monthly rate = 8.5 ÷ 12 ÷ 100 = 0.007083
- n = the number of monthly instalments = 20 × 12 = 240
- Work out (1 + r)n = (1 + 0.007083)240 = 5.4412.
- Top of the fraction: P × r × 5.4412 = 96355.
- Bottom of the fraction: 5.4412 − 1 = 4.4412.
- Divide: EMI = ₹21,696 per month.
Over 240 months you pay ₹52,06,939, of which ₹27,06,939 is interest. You can check any case with the EMI calculator.
How each EMI splits into interest and principal
In the first month, interest is charged on the full ₹25,00,000. So the first EMI is mostly interest. As the balance falls, the interest part shrinks and the principal part grows:
| Month | Interest part | Principal part | Balance left |
|---|---|---|---|
| 1 | ₹17,708 | ₹3,987 | ₹24,96,013 |
| 2 | ₹17,680 | ₹4,015 | ₹24,91,997 |
| 3 | ₹17,652 | ₹4,044 | ₹24,87,953 |
This is why paying extra early in a loan saves the most interest, as we show in our guide on prepaying a home loan.
Flat rate vs reducing rate
Some lenders, especially for two-wheeler and personal loans, quote a flat rate. A flat rate charges interest on the original loan amount for the whole period, even though you keep repaying it. A reducing-balance rate charges interest only on what you still owe. They are not comparable at the same number.
Take ₹5,00,000 for 5 years at 8%:
| Flat 8% | Reducing 8% | |
|---|---|---|
| Monthly EMI | ₹11,667 | ₹10,138 |
| Total interest | ₹2,00,000 | ₹1,08,292 |
The flat-rate EMI is the same as a reducing-balance loan at about 14.1%. So always ask for the rate on a reducing balance, or compare the EMI, and use the bike loan EMI calculator to check a quote.
How much EMI can you afford?
A common guideline, used by many lenders and planners, is that all your loan EMIs together should stay within about 40% of your monthly take-home pay. It is a rule of thumb, not an RBI limit. With a take-home of ₹1,00,000, that is ₹40,000 a month. At 8.5% for 20 years, an EMI of ₹40,000 matches a loan of about ₹46.09 lakh. Remember that you also need money for rent or running costs, savings and an emergency fund, so staying well below 40% is safer. If your income is uneven, use a lower share.
Three ways to lower your EMI cost
- Choose a shorter tenure if you can afford the higher EMI. Total interest drops sharply.
- Make a larger down payment so you borrow less.
- Prepay when you can. Check your loan agreement for charges, since RBI rules on prepayment charges differ by loan type.
Keep reading
- Home Loan Prepayment vs SIP: Which Is Better? (The Math) — Loans, 7 min read
- How to Improve Your CIBIL Score: 9 Practical Steps — Credit, 7 min read
- How Much Emergency Fund Do You Need? A Simple Formula — Money basics, 6 min read
- The 50-30-20 Budget Rule for India: How to Use It on Your Salary — Money basics, 6 min read
Frequently asked questions
What is the formula for EMI?
EMI = P × r × (1 + r)ⁿ ÷ [(1 + r)ⁿ − 1], where P is the loan, r the monthly interest rate and n the number of months.
How do I find the monthly interest rate?
Divide the yearly rate by 12, then by 100. An 8.5% yearly rate is 8.5 ÷ 12 ÷ 100 = 0.007083 a month.
Why is most of my first EMI interest?
Because interest is charged on the outstanding balance, which is highest at the start. As you repay, the balance falls, so the interest part falls and the principal part rises.
Is a flat interest rate the same as a reducing rate?
No. A flat rate is charged on the original amount for the full period, so it costs far more. In our example, a 8% flat rate equals about 14.1% on a reducing balance.
Sources: RBI — Pre-payment Charges on Loans Directions, 2025 · Reserve Bank of India