Prepay the loan or invest the surplus?

A rupee used to prepay a loan earns a guaranteed saving equal to the interest you no longer pay on that principal (after fees). A rupee invested may earn a return that is uncertain and often taxable.

Rough rule of thumb: if your loan’s effective interest rate (after tax effects, if any) is higher than a realistic after-tax return you expect on the investment — with risk you can accept — prepaying is often attractive. If you can earn more after tax and risk than the loan costs, investing can win. Real life also needs emergency funds and goals.

Use the Loan Prepayment calculator: enter outstanding principal, rate, remaining tenure, and a planned prepay month and amount. Choose reduce tenure (usually larger interest save) or reduce EMI.

Note interest vs the no-prepay baseline. That number is your “guaranteed return” from prepaying (before any prepayment charges). Then ask whether an investment is likely to beat that, after tax and risk, over a similar horizon.

Emergency buffer: do not empty savings to prepay if you would then need high-cost borrowing later.

Lock-in and penalties: some personal loans and older products charge for foreclosure or part-payment — subtract fees from the benefit.

Floating loans: future rate hikes raise the value of prepaying; rate cuts lower it. Stress-test with floating resets plus a prepay.

Behaviour: some people sleep better with lower debt even if pure math is close — that is a valid preference, not a formula.

This is an educational framework. Tax rules, product terms, and your risk capacity differ. Confirm numbers with your lender and a qualified adviser when stakes are high.