What's inside an EMI
An EMI, or Equated Monthly Instalment, is a fixed monthly payment with two parts:
- Interest: the cost of the balance you still owe that month.
- Principal: the rest of the EMI, which reduces what you owe.
Each month, the balance is a little lower, so less of your EMI goes to interest and more goes to principal. The EMI itself doesn't change unless your rate or your loan does.
The EMI formula
EMI = P × r × (1 + r)n ÷ ((1 + r)n − 1)
Here, P is the loan amount, r is the annual rate divided by 12 and then by 100, and n is the number of months. You don't need to work this out by hand: every eligibility calculator on this site shows your EMI, and has a repayment schedule you can open under it.
A home loan, year by year
Take a ₹50 lakh loan at 8% over 20 years. The EMI is ₹41,822. In the first month, interest is ₹33,333, so only ₹8,489 reduces your loan.
| Year | Principal paid | Interest paid | Balance at year end |
|---|---|---|---|
| 1 | ₹1,05,683 | ₹3,96,181 | ₹48,94,317 |
| 5 | ₹1,45,385 | ₹3,56,479 | ₹43,76,279 |
| 10 | ₹2,16,601 | ₹2,85,263 | ₹34,47,031 |
| 15 | ₹3,22,702 | ₹1,79,162 | ₹20,62,596 |
| 20 | ₹4,80,777 | ₹21,087 | ₹0 |
Over 20 years you'd pay about ₹50.37 lakh in interest, slightly more than the loan itself. Principal doesn't overtake interest until month 137, more than 11 years in, and half of the loan isn't repaid until month 164. That's normal for a long loan, and it surprises many borrowers who check their balance after a few years.
How tenure changes the cost
A longer tenure lowers the EMI, but it raises the total interest by much more. Here is the same ₹50 lakh loan at 8%.
| Tenure | EMI | Total interest |
|---|---|---|
| 10 years | ₹60,664 | ₹22.80 lakh |
| 15 years | ₹47,783 | ₹36.01 lakh |
| 20 years | ₹41,822 | ₹50.37 lakh |
| 25 years | ₹38,591 | ₹65.77 lakh |
| 30 years | ₹36,688 | ₹82.08 lakh |
Going from 20 to 30 years saves ₹5,134 a month but adds about ₹31.71 lakh in interest. A longer tenure can still be sensible, because it lets you qualify for the loan and gives you breathing room. Just try to prepay when you can.
What prepayment really saves
A prepayment goes straight to the principal, so it cuts all the future interest on that amount. The earlier it's made, the more it saves. Here is a single ₹2 lakh prepayment on the same 20-year loan, keeping the EMI the same.
| When you prepay | Interest saved | Loan ends sooner by |
|---|---|---|
| After 2 years | ₹5.91 lakh | 18 months |
| After 15 years | ₹92,076 | 6 months |
Should you cut the EMI or the tenure?
After a prepayment, lenders often let you lower either your EMI or your remaining tenure. Cutting the tenure usually saves more interest, while cutting the EMI gives you more room each month. If your budget is comfortable, a shorter tenure is usually the better deal. Tell your lender which you want, since it may not ask.
Before you prepay
- Check for charges. RBI directions bar prepayment charges on floating-rate loans taken by individuals for non-business purposes, for loans sanctioned or renewed from 1 January 2026. Fixed-rate loans may carry charges, so check your agreement.
- Keep an emergency fund. Money paid into a loan is hard to get back in a hurry.
- Clear costly debt first. Credit card dues and personal loans usually cost much more than a home loan.
- Get a statement afterwards. Check that the amount has reduced your principal and that your new schedule looks right.
Rates also matter here. See fixed vs floating rates for how a rate change can alter your schedule, and balance transfers if your rate is high.