Why does a relatively small extra payment save so much interest?

Every extra rupee applied to principal early in the loan removes that rupee from the balance for every remaining month of the original tenure -- since interest is charged on the outstanding balance each month, a rupee paid off in year 2 saves interest for 18+ more years (in a 20-year loan), which is why prepayment savings can add up to several times the extra amount paid in total.

Does prepayment reduce my EMI or shorten my loan term?

In this calculator's model, your EMI stays fixed at its original amount, and the loan simply finishes early once the accelerated payoff brings the balance to zero -- this is the "reduce tenure" approach to prepayment. Some lenders instead offer a "reduce EMI" option that keeps the original tenure but lowers your monthly payment; that produces smaller total interest savings than reducing tenure, since the loan still runs its full original length.

Why does the tool warn about prepayment penalties?

Some loans -- particularly fixed-rate loans in certain markets -- charge a penalty for paying off principal ahead of schedule, since the lender loses expected future interest income. This calculator shows the savings assuming no such penalty; if your specific loan has one, you'd need to net that penalty against the interest savings shown here to know your real benefit.

Would the extra payment be better invested elsewhere instead?

That depends on your loan rate versus your expected investment return -- prepayment is mathematically equivalent to earning a guaranteed, risk-free return equal to your loan's interest rate. If you can reliably invest elsewhere at a meaningfully higher after-tax return, investing may build more wealth; if not, or if you value the certainty and reduced monthly obligation, prepayment is often the safer choice.

Loan Prepayment Savings Calculator

Enter your loan details and an extra amount you could pay each month — see exactly how much time and interest that saves you.

How Loan Prepayment Savings Calculator Works

Paying extra toward a loan's principal each month doesn't just chip away at the balance faster -- it removes that principal from every future month's interest calculation too, which compounds into savings much larger than the extra payment itself. This calculator runs the full month-by-month amortization, with and without your extra payment, to show exactly how much time and interest that discipline actually saves.

Formula & Method

Each month, interest is calculated on the current outstanding balance (balance × monthly rate), and the rest of the fixed EMI -- plus your extra payment -- goes toward reducing principal. This is simulated month-by-month rather than solved with a single formula, because the extra payment changes the balance trajectory in a way a closed-form equation can't capture: the loan pays off early once the balance hits zero, and every month after that needed no further interest. The tool runs this simulation twice -- once with no extra payment (baseline) and once with your entered extra amount -- and reports the difference in total interest paid and payoff time.

Worked Example

A ₹10,00,000 loan at 8.5% over 20 years has an EMI of about ₹8,678. Adding just ₹5,000 extra toward principal every month cuts the payoff time from 240 months down to 104 months (about 11 years 4 months earlier) and reduces total interest paid from roughly ₹10.83 lakh to about ₹4.14 lakh -- a savings of about ₹6.69 lakh, more than the total extra payments made, because each rupee paid early stops accruing interest for every remaining month of the original tenure.

Frequently Asked Questions

Why does a relatively small extra payment save so much interest?: Every extra rupee applied to principal early in the loan removes that rupee from the balance for every remaining month of the original tenure -- since interest is charged on the outstanding balance each month, a rupee paid off in year 2 saves interest for 18+ more years (in a 20-year loan), which is why prepayment savings can add up to several times the extra amount paid in total.
Does prepayment reduce my EMI or shorten my loan term?: In this calculator's model, your EMI stays fixed at its original amount, and the loan simply finishes early once the accelerated payoff brings the balance to zero -- this is the "reduce tenure" approach to prepayment. Some lenders instead offer a "reduce EMI" option that keeps the original tenure but lowers your monthly payment; that produces smaller total interest savings than reducing tenure, since the loan still runs its full original length.
Why does the tool warn about prepayment penalties?: Some loans -- particularly fixed-rate loans in certain markets -- charge a penalty for paying off principal ahead of schedule, since the lender loses expected future interest income. This calculator shows the savings assuming no such penalty; if your specific loan has one, you'd need to net that penalty against the interest savings shown here to know your real benefit.
Would the extra payment be better invested elsewhere instead?: That depends on your loan rate versus your expected investment return -- prepayment is mathematically equivalent to earning a guaranteed, risk-free return equal to your loan's interest rate. If you can reliably invest elsewhere at a meaningfully higher after-tax return, investing may build more wealth; if not, or if you value the certainty and reduced monthly obligation, prepayment is often the safer choice.

Loan Amount

Interest Rate (% per annum)

Loan Tenure (Years)

Extra Monthly Payment

This assumes the extra amount goes entirely toward reducing your outstanding principal each month, and that your bank recalculates interest on the reduced balance immediately (the standard "reducing balance" method most loans use) — check that your lender doesn't charge a prepayment penalty first.

— Interest Saved