Why your first EMI is 82% interest.
On a ₹50.0 L loan at 8.5% for 20 years, your EMI is ₹43,391 — but the first month, ₹35,417 of it is interest and only ₹7,974 repays the loan. You don't cross 50% repaid until around year 14.
The mechanics nobody explains at loan signing
An EMI is engineered to be the same number every month for the full tenure — that's its whole appeal. But underneath that flat payment, two moving parts trade places every single month. Interest is calculated on whatever you still owe; the rest of the EMI goes to principal. Early on you owe a lot, so interest devours the payment. Two decades later you owe little, so nearly the whole EMI chips away at principal. The payment never changes — the composition changes completely.
Run the actual numbers for a typical Indian metro home loan — ₹50.0 L at 8.5% over 20 years. The formula (EMI = P×r×(1+r)ⁿ ÷ ((1+r)ⁿ−1), with r the monthly rate) produces an EMI of ₹43,391. In month one, the bank charges 8.5%÷12 on the full ₹50.0 L: that's ₹35,417 in interest. Your loan shrinks by just ₹7,974. If you total every payment over 20 years, you repay ₹1,04,13,879 — the house costs you ₹54.1 L in interest on top of the principal.
The milestones that matter
| End of year | Still owed | Interest paid so far |
|---|---|---|
| Year 5 | ₹44.1 L | ₹20.1 L |
| Year 10 | ₹35.0 L | ₹37.1 L |
| Year 14 — half repaid | ₹24.4 L | ₹47.3 L |
| Year 15 | ₹21.1 L | ₹49.3 L |
| Year 20 | ₹0.0 L | ₹54.1 L |
Notice the asymmetry: five years in — a quarter of the tenure — you've barely dented the principal, yet you've already handed the bank more than ₹20.1 L in interest. This is why refinancing to a cheaper rate is most valuable early in a loan, and nearly pointless in the final years: the interest is front-loaded, so the savings are too.
The single cheapest trick in home finance
Pay one extra EMI per year — a 13th payment, applied straight to principal. On this loan it shortens the tenure by about 3 years 4 months and saves roughly ₹10.3 L — 19% of the total interest — because a prepaid rupee at year 2 stops accruing 8.5% for the remaining eighteen years. Indian floating-rate home loans carry no prepayment penalty by RBI rule, so the only cost is opportunity cost. Bonus math: prepaying an 8.5% loan is a guaranteed, tax-free 8.5% return — compare that honestly with what your money would otherwise earn.
CFP® with 12+ years in mortgage & retirement planning.