EMI · prepayment · amortisation
What the EMI really costs
The monthly figure is the easy part. The interesting number is the interest you will pay over the whole loan — and how much of it disappears if you add even a little to each payment. Set the loan below; the yearly schedule and the saving update as you type.
Move the numbers, watch the interest
Nothing is sent anywhere. Tenure is in years; the schedule uses monthly compounding, which is how Indian lenders quote home, car and personal loans.
Leave this at zero to see the plain schedule. Any amount here is applied to principal every month, on top of the EMI.
₹21,696
for 20 years · ₹52,06,939 paid in total
- Principal
- ₹25,00,000
- Total interest
- ₹27,06,939
- Interest share
- 52%
Standard reducing-balance EMI. Illustrative only — not a loan offer or financial advice. Your lender's compounding, fees and disbursement schedule will move the real number.
The two numbers that matter
EMI is level. Interest is not.Your instalment stays flat, but its composition flips. In year one most of it is interest; in the final years almost all of it is principal. That is why early prepayments are worth far more than late ones.
Tenure is the real lever.Stretching a loan to lower the EMI raises the total interest, often by more than people expect. Compare two tenures at the same amount and look at the total, not the monthly figure.
Formula used: EMI = P × r × (1 + r)n ÷ ((1 + r)n − 1), with r = annual rate ÷ 12 ÷ 100 and n = months. The schedule is simulated monthly, then aggregated by year for the table and CSV.
Questions about the maths
- How is the EMI calculated?
- Standard reducing-balance formula: EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), where P is the principal, r is the monthly rate (annual ÷ 12 ÷ 100) and n is the number of months. The schedule is then simulated month by month so prepayments behave the way a lender would apply them.
- What does the extra monthly payment actually do?
- It goes straight to principal on top of your EMI, which shortens the tenure rather than reducing the monthly instalment. The tool shows both effects — months cut and interest avoided — because tenure reduction is where most of the saving comes from early in a loan.
- Why does a small prepayment save so much interest?
- Because interest is charged on the outstanding balance, and the outstanding balance is largest in the early years. A rupee of principal repaid in year two stops accruing interest for the remaining eighteen years of a twenty-year loan.
- Does this work offline?
- Yes. There is no server behind it — the maths runs in your browser, so the page keeps working once loaded, and your loan figures are never sent anywhere.
- Is this a loan offer or financial advice?
- No. It is an illustrative calculator. Lenders differ on compounding, processing fees, insurance bundling and disbursement timing, all of which move the real number. Check your sanction letter before making a decision.
More tools: the full list, including the app development cost calculator.