Prepaying a loan versus investing the extra EMI

How to compare a prepayment on the EMI calculator with an SIP of the same rupees, including tax on interest saved versus market risk.

By Sachin S Marnur · Software engineer, Bengaluru, India · Last reviewed 29 August 2026

The internet loves a false binary: “never prepay, SIP always wins at 12%.” Home loans in the early years are mostly interest, look at the EMI calculator amortisation so extra rupees in year 3 buy more principal than extra rupees in year 18. Equity SIPs are not a guaranteed 12%. This page is how I compare the two without a motivational quote.

Same rupees, two worksheets

Take ₹10,000 a month you could either put as a regular prepayment (or a higher EMI) or as a SIP. On the EMI tool, note total interest over the full tenure. Then reduce principal (or tenure) by the equivalent of that extra cash and note total interest again. The difference is interest avoided a risk-free-ish return equal to the loan rate, ignoring tax and prepayment fees.

On the SIP calculator, run ₹10,000 at 8% and at 12% with inflation on. The 8% real column is the honest rival to a 8.5% home loan. If 8% real SIP still loses to interest saved, prepay. If you only “win” at 15% expected return, you are arguing with a YouTube thumbnail. The 12% slider is not a forecast.

Tax and 80C muddy home loans

Interest on a home loan can have deduction limits; principal can sit in 80C. Prepaying principal may reduce a deduction you liked. Personal loans usually have no such romance personal loan calculator and 16–24% rates make SIP-as-rival a bad joke. Clear expensive unsecured debt before you debate Nifty.

Emergency cash is not extra EMI

Do not empty the FD emergency sleeve to prepay a 8% home loan. Sequence risk for a household is a job loss plus an EMI, not a chart. Keep the buffer, then split leftover between prepay and SIP if you must do both. A hybrid is allowed. A slogan is not.

Banks differ on part-prepayment charges and on whether they cut tenure or EMI. The calculator will not know your sanction letter. Use it to size the interest, then ask the bank which lever they will actually move.

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