Prepayment: reduce your tenure or reduce your EMI? The math, worked out
Your bank's app asks you to pick one after a prepayment and rarely explains what you're giving up either way. Here's the actual difference.
Published 25 July 2026
Two modes, same lump sum, different outcomes
When you make a lump-sum prepayment, a lender gives you two options: keep the EMI the same and finish earlier (reduce tenure), or keep the tenure the same and pay less each month (reduce EMI). Both apply the same money to the same loan. They do not save you the same amount of interest — and the gap is bigger than most people expect.
The setup
A ₹30 lakh loan at 9%, originally 20 years (240 months), EMI ≈ ₹26,992. Five years in (60 months paid, on schedule, no prior prepayments), the outstanding balance is about ₹26.61 lakh. At this point, a ₹5 lakh lump sum becomes available — say, a bonus — and it goes toward the loan, bringing the balance down to about ₹21.61 lakh with 180 months still nominally remaining.
Left untouched, those remaining 180 months would cost about ₹21.97 lakh in interest. That's the baseline both prepayment modes are measured against.
Reduce tenure: EMI stays at ₹26,992
Holding the EMI constant on the reduced ₹21.61 lakh balance, the loan pays off in about 123 months instead of 180 — roughly 57 months, nearly 5 years, shaved off. Interest paid from this point on: about ₹11.53 lakh, against a ₹21.97 lakh baseline. Total interest saved: roughly ₹10.44 lakh.
Reduce EMI: tenure stays at 180 months
Re-amortizing the same ₹21.61 lakh balance over the same 180 months instead drops the EMI to about ₹21,920 — about ₹5,071 less every month, cash flow you get back immediately. Interest paid over those 180 months: about ₹17.84 lakh. Total interest saved: roughly ₹4.13 lakh.
The same ₹5 lakh, a ₹6.3 lakh difference in outcome
Reduce-tenure saves roughly ₹6.3 lakh more in total interest than reduce-EMI, on the exact same prepayment. That isn't a rounding effect — it's the mechanical result of interest being charged on the outstanding balance every month. Reduce-tenure keeps you paying down principal at the old, higher rate of attack; reduce-EMI spreads the relief out and lets the bank keep charging interest on a balance that shrinks more slowly.
None of this means reduce-EMI is a bad choice. If the ₹5,071 in monthly breathing room is what keeps your budget comfortable — after a job change, a new dependent, rising costs elsewhere — that's a real value the interest-saved number doesn't capture. The point isn't that one mode is right; it's that "how much less will I actually pay" is a very different question from "how much lower is my monthly number," and a lender's app rarely shows you both.
If you have several loans, the order matters too
The same logic extends further when you're not just deciding tenure-vs-EMI on one loan but choosing which of several loans to throw surplus cash at first — pay the highest-rate loan down first (avalanche) and you minimize total interest across the whole portfolio; close the smallest balance first (snowball) and you free up a monthly EMI sooner, which then compounds into faster payoff of what's left. That comparison is what the Loan Repayment Optimizer runs automatically.
Important information
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