You have a surplus: a bonus, a maturing deposit, or the proceeds of a sale. Your home loan is running at 8.5%. Should the money go into the loan, or into the market?
The usual answer is to compare the loan rate against your expected investment return and pick the higher one. That is a reasonable starting point, and it is incomplete in ways that change the conclusion.
Timing dominates the arithmetic
Because interest is charged on the outstanding balance, and the balance falls slowly at first, prepayment is dramatically more powerful early in the loan than late.
The same rupee prepaid in year three removes interest that would otherwise have compounded across the remaining seventeen years. Prepaid in year eighteen, it removes very little, because most of the interest on that loan has already been paid. Any comparison that ignores where you are in the tenure is missing the largest variable.
Look at your own amortisation schedule before deciding. The interest column tells you immediately whether prepayment is still doing meaningful work.
Compare the right numbers
The return on prepayment is guaranteed and risk-free: you save exactly the loan rate, with certainty. An investment return is expected, not guaranteed, and is taxable on realisation.
So the honest comparison is not 8.5% against an assumed 12% equity return. It is 8.5% guaranteed against a risk-adjusted, post-tax expected return. That gap is narrower than it first appears, and it narrows further if you are still claiming the interest deduction under Section 24(b) under the old regime, which lowers your effective borrowing cost.
Reduce the EMI or the tenure?
When you prepay, most lenders let you choose. Reducing the tenure while keeping the EMI unchanged saves substantially more interest, because you exit the loan sooner. Reducing the EMI improves monthly cash flow but leaves you paying for the full original term.
Unless you need the monthly relief, cutting the tenure is almost always the better choice, and lenders do not always volunteer that this is an option.
Things worth doing before either
- Build an emergency fund of six months' expenses: a prepaid home loan cannot be un-prepaid when you need cash
- Clear every high-cost debt first; credit card revolving balances and personal loans dwarf any home loan rate
- Ensure adequate term and health cover, so an unforeseen event does not force a distress sale
- Confirm your foreclosure terms: floating-rate loans to individuals carry no charges, but fixed-rate loans may
A reasonable default
For most borrowers in the first half of a home loan, with an emergency fund in place and no high-cost debt outstanding, partial prepayment is a sound use of surplus, particularly when directed at reducing the tenure.
In the later years, with the interest component already small, the case weakens considerably and investing the surplus generally makes more sense.
This is general information, not personalised advice. Your tax regime, income trajectory, existing portfolio and risk tolerance all bear on the decision, and a qualified financial adviser can weigh them for your specific situation in a way an article cannot.