What an EMI is made of
An equated monthly instalment is the same amount every month, but it is not the same money every month. Each payment is split between interest on the balance you still owe and repayment of that balance.
Early on, almost all of it is interest. The outstanding principal is at its largest, so the interest charged on it is too, and very little of your payment reduces the debt. Late in the loan the balance is small, interest is small, and nearly the whole instalment goes to principal.
This front-loading is the single most useful thing to understand about a loan, and the schedule in the calculator above shows it directly. On a twenty-year home loan, a payment made in year three repays a fraction of what the identical payment repays in year eighteen.
The formula
EMI = [P × R × (1 + R)^N] / [(1 + R)^N − 1]
- P is the principal
- R is the monthly interest rate — the annual rate divided by twelve
- N is the number of monthly instalments
Note the convention. Lenders use a nominal monthly rate: 9% a year is 0.75% a month. This differs from the effective monthly rate used for SIP calculations, and using the wrong one here understates every EMI.
On ₹10,00,000 at 9% for five years, the EMI is about ₹20,758. Across sixty payments that totals roughly ₹12,45,501, so the loan costs about ₹2,45,501 in interest — just under a quarter of the amount borrowed.
What each input does to the cost
The rate. Direct and unforgiving. On a ₹50 lakh home loan over twenty years, one percentage point is worth several lakh in total interest. Negotiating the rate, or refinancing later, is usually worth more than any other move available to a borrower.
The tenure. This is where intuition fails. A longer tenure lowers the EMI and raises the total cost, often sharply. Stretching a ₹50 lakh loan from fifteen years to twenty-five cuts the monthly payment noticeably while adding a very large amount of interest over the life of the loan. Use the calculator to see both numbers before choosing a tenure for affordability alone.
The amount. A larger down payment reduces the principal, and the interest saved compounds across the whole term.
Prepayment
Because interest is charged on the outstanding balance, a prepayment removes not only that amount of principal but every future interest payment that principal would have attracted.
A prepayment made in year two of a twenty-year loan saves far more than the same amount in year fifteen. Floating-rate home loans to individuals cannot carry a prepayment penalty under RBI rules, which makes early prepayment one of the most reliable returns available to a borrower — effectively a risk-free return equal to the loan rate, and untaxed.
Most lenders will let you choose whether a prepayment reduces the EMI or shortens the tenure. Shortening the tenure saves more.
How to use this calculator
- Enter the loan amount you intend to borrow.
- Set the rate of interest the lender has quoted. Compare quotes on the annual rate, not the EMI.
- Set the loan tenure in years.
- Read the EMI, principal, total interest and total payable, then open the year-by-year schedule to see the split change over time.
A useful habit: before settling on a tenure, run two. The shorter one usually costs less in total by an amount worth the higher instalment.
What the calculator does not include
The EMI is not the whole cost of a loan. Processing fees, documentation and legal charges, valuation, stamp duty on the mortgage, and compulsory insurance are all separate, and several are charged up front. Ask for the all-in cost rather than the rate.
The calculator also assumes a fixed rate throughout. Most home loans in India are floating and reprice with the external benchmark, which changes either the EMI or the tenure. Re-run the numbers when your rate resets.