The short answer
Banks charge interest each month on the outstanding balance at one twelfth of the annual rate. Your EMI pays that interest first and the rest reduces principal. On a ₹50 lakh, 20-year loan at 8.5%, the EMI is ₹43,391, of which ₹35,417 is interest in month 1. Total interest comes to about ₹54.14 L.
The reducing-balance method
Almost every home loan in India charges interest on a reducing balance. Each month the lender works out interest on the principal still outstanding, at one twelfth of the annual rate. Your EMI first pays that interest, and whatever is left over reduces the principal. Next month the balance is a little smaller, so the interest is a little smaller and a little more of the same EMI goes towards principal.
The EMI itself is fixed so that the loan is fully repaid by the last instalment:
EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1)
Here P is the loan amount, r is the monthly rate (annual rate ÷ 12 ÷ 100) and n is the number of monthly instalments. For a loan of ₹50 lakh at 8.5% over 20 years, r is 0.7083% a month and n is 240, which gives an EMI of ₹43,391.
How the first EMI is split
In month 1 the full ₹50 lakh is outstanding. Interest for the month is ₹50,00,000 × 0.7083% = ₹35,417. That leaves only ₹7,974 of the ₹43,391 EMI to reduce the principal, so the balance after the first instalment is ₹49,92,026.
Put differently, 82% of your first EMI is interest. This is why borrowers are often surprised to see how little the outstanding balance has moved after the first year or two. Nothing is wrong with the loan: it is simply how a long reducing-balance loan works when the balance is at its largest.
Interest and principal year by year
The table follows the same ₹50 lakh loan. Each row shows what you pay in that year of the loan, not the running total.
| Loan year | Interest paid | Principal repaid | Interest share of EMIs | Balance at year end |
|---|---|---|---|---|
| Year 1 | ₹4,21,182 | ₹99,511 | 81% | ₹49,00,489 |
| Year 2 | ₹4,12,387 | ₹1,08,307 | 79% | ₹47,92,181 |
| Year 5 | ₹3,81,053 | ₹1,39,641 | 73% | ₹44,06,359 |
| Year 10 | ₹3,07,420 | ₹2,13,274 | 59% | ₹34,99,691 |
| Year 15 | ₹1,94,961 | ₹3,25,733 | 37% | ₹21,14,937 |
| Year 20 | ₹23,202 | ₹4,97,492 | 4% | ₹0 |
- In the first five years you pay ₹20.1 L of interest but repay only ₹5.94 L of principal.
- Principal first exceeds interest in month 143, which is in year 12. From then on the balance falls noticeably faster each year.
- Because the early years are interest-heavy, a prepayment made in the first few years saves far more than the same amount paid near the end.
What a small change in rate or tenure does
Two levers decide your total interest: the rate and the number of years. The table keeps the loan at ₹50 lakh and changes one lever at a time.
| Scenario | EMI | Total interest | Change in interest |
|---|---|---|---|
| 8% for 20 years | ₹41,822 | ₹50,37,281 | −₹3,76,598 |
| 8.5% for 20 years (base) | ₹43,391 | ₹54,13,879 | – |
| 9% for 20 years | ₹44,986 | ₹57,96,711 | +₹3,82,833 |
| 8.5% for 15 years | ₹49,237 | ₹38,62,656 | −₹15,51,223 |
A rise of just 0.5 percentage points adds ₹3.83 L of interest over the life of the loan. Choosing 15 years instead of 20 raises the EMI by ₹5,846 a month but saves ₹15.51 L. If the higher EMI fits comfortably within your budget, the shorter tenure is usually the better choice.
Floating rates and what happens when they change
Most home loans today carry a floating rate linked to an external benchmark, usually the RBI repo rate. Your rate is the benchmark plus a spread fixed by the lender, and it is reset at regular intervals set out in your loan agreement. When the repo rate moves, the interest charged on your outstanding balance moves with it from the next reset.
Lenders usually absorb a rate rise by extending the tenure and keep the EMI unchanged. That feels painless, but it can add years of payments. Ask the lender how it will handle a reset, and request a higher EMI instead if your budget allows.
How to check the interest on your own loan
- Take the outstanding principal, current rate and remaining months from your latest loan statement.
- Divide the annual rate by 12 to get the monthly rate, and multiply it by the outstanding balance to get this month's interest.
- Subtract that interest from your EMI to see how much principal this instalment repays.
- Compare the result with the lender's repayment schedule, and ask for a revised schedule after every rate reset or prepayment.
Frequently asked questions
Why is most of my EMI going towards interest?
In the early years the outstanding balance is at its highest, so the monthly interest on it takes up most of the EMI. The interest share falls every month as the balance reduces.
Is home loan interest calculated daily or monthly?
Most lenders compute interest on a monthly reducing balance, which is what EMI calculators assume. Some calculate it on a daily balance; check the loan agreement or ask your lender.
Does my EMI change when the repo rate changes?
For a loan linked to the repo rate, the interest rate changes at the next reset. Lenders usually change the tenure first and keep the EMI the same, but you can ask to change the EMI instead.
How can I reduce the total interest on my home loan?
Choose the shortest tenure you can afford, prepay whenever you have surplus funds, raise your EMI as income grows, and move to a cheaper lender if the rate gap justifies the switching costs.
What is the difference between a fixed and a floating home loan rate?
A fixed rate stays the same for an agreed period. A floating rate is linked to a benchmark such as the repo rate and changes at each reset, so your interest cost can rise or fall.