How this calculator works
At the defaults, ₹5,000 extra each month ends the loan in Jun 2042 and saves about ₹13.89 lakh in interest.
- Step 1Interest is charged first₹35,417the balance times the monthly rate
- Step 2The rest repays the loan₹12,974principal paid in the first month, including any extra
- Step 3The balance shrinks₹49,87,026next month’s interest is charged on this smaller amount
The yearly rate is divided by twelve. Each month, interest is added to the balance, then your payment is taken off. Early payments are mostly interest; later ones are mostly principal. The final payment is trimmed so the balance lands on exactly zero.
What the result leaves out
- Fees and taxesProcessing charges, part-payment fees, taxes and insurance are not included.
- Rate changesOne fixed rate is used for every month. A floating-rate reset would change the figures.
- Lender timingDue dates, daily-interest rules and rounding can make a lender’s schedule differ slightly.
Worked example
- Monthly rate
i = annual rate ÷ (12 × 100)- Scheduled payment
M = P × i ÷ (1 − (1 + i)^−n)- Each month
interest = balance × i; principal = payment − interest
- Ploan amount ₹50,00,000
- imonthly rate 0.71%
- nnumber of scheduled payments 240
- Scheduled monthly paymentordinary-annuity payment₹43,391
- First month interestbalance × monthly rate₹35,417
- First month principalpayment + extra − interest₹12,974
- Interest with no extra paymentn × payment − P₹54,13,879
- Interest saved by the extra paymentsno-extra interest − plan interest₹13,89,250
The first payment falls one month after the start month. Figures are rounded for display; the calculation keeps full precision.
Reading your result
- Scheduled only20 yearsTotal interest about ₹54.14 lakh.
- With extra payments15 years 7 monthsTotal interest about ₹40.25 lakh; 4 years 5 months earlier.
- Interest, scheduled payments only
- Interest, with extra payments
The yearly table groups the same monthly rows by calendar year. Open the monthly table to see each payment, including the extra part and the closing balance.
Why early payments are mostly interest
Each month's interest is charged on the balance still owed, so the interest share is largest at the start and shrinks every month.
That is why an extra payment early in a loan saves more than the same amount near the end. The loan prepayment calculator compares cutting the term with lowering the EMI after a part-payment.
The EMI calculator gives the payment alone, and the loan tenure calculator works out how long a chosen payment takes. If another lender offers a lower rate, weigh the switch with the loan balance transfer calculator.
Common mistakes
Mistake: Treating the schedule as your lender’s final statement.
Instead: Compare it with the written schedule and check part-payment rules in your loan documents.
Mistake: Entering the full instalment as the extra payment.
Instead: Enter only the amount paid on top of the scheduled payment.
Mistake: Assuming a floating rate will stay fixed.
Instead: Re-run the calculation when your lender changes the rate.
This calculator does not assess affordability or recommend a repayment choice. Use your lender’s written schedule for exact obligations and consult a qualified professional about your circumstances.
Checking the method
A separate script rebuilds every test schedule month by month, and checks the simpler cases against closed-form formulas too.
Read how we test our calculators, or browse more money calculators.