ReckonBoxHow the EMI calculator works
An EMI, or equated monthly installment, is the fixed amount you pay a lender every month until a loan is cleared, made up of interest on the balance still owed plus a slice of the principal. This calculator takes your loan amount, the interest rate and the tenure, then shows the EMI, the total interest, a year-by-year schedule, what the same loan would cost at a flat rate, and what paying a little extra each month would save. Enter the rate your bank quotes and it works for a home, car, personal, two-wheeler or gold loan alike.
On the default numbers the cost of borrowing is clear. A Rs 10,00,000 loan at 9% for 10 years has an EMI of Rs 12,668, and across 120 months you repay Rs 15,20,160, of which Rs 5,20,160 is interest. Stretch the tenure and the EMI falls but the total interest climbs, which is the trade every borrower makes.
The EMI formula
EMI is P times r times (1 + r) to the power n, all divided by (1 + r) to the power n minus 1, where P is the loan amount, r the monthly rate and n the number of months. The monthly rate is the annual rate divided by 12 and by 100, so 9% a year is 0.0075 a month. Feed in Rs 10,00,000, 0.0075 and 120 and the formula returns Rs 12,668, the same figure the bank calculators show.
Interest each month is charged only on the balance you still owe, which is why this is called the reducing-balance method. As you chip away at the principal, the interest part of each EMI shrinks and the principal part grows, even though the EMI itself never changes.
The year-by-year schedule
A loan amortization schedule is a table that splits every EMI into its interest and principal parts and tracks the balance falling to zero. Early in the loan the balance is large, so most of each EMI is interest; late in the loan the balance is small, so most of it is principal. On the default loan the first year pays about Rs 86,000 of interest and only Rs 66,000 of principal, while the final year is almost all principal.
The schedule above lays this out one year at a time. It is why paying a home loan for five years and then checking the balance can be a shock: you have paid a lot, but much of it went to interest, and the principal has barely moved.
Flat rate or reducing rate
A reducing-rate loan charges interest only on the outstanding balance, while a flat-rate loan charges interest on the full amount for the whole tenure, so a flat rate always costs more. Lenders sometimes quote a flat rate because the number looks smaller, but it hides an effective cost close to double. This calculator shows both so the gap is impossible to miss.
| Method | EMI | Total interest (Rs 10L, 9%, 10 yr) |
|---|---|---|
| Reducing balance | Rs 12,668 | Rs 5,20,160 |
| Flat rate | Rs 15,833 | Rs 9,00,000 |
A 12% flat rate works out close to a 21% reducing rate, and a 10% flat rate to about 18%. So when a lender offers a flat rate, convert it in your head to the reducing equivalent before comparing it with a home loan quoted the normal way.
What prepaying saves
Because interest is charged on the balance you still owe, any extra you pay cuts that balance and every future interest charge on it, so the loan ends sooner. Add an extra amount to the EMI in the calculator and it shows the months and the interest that disappear. On the default Rs 10,00,000 loan, paying Rs 5,000 extra a month clears it in about 74 months instead of 120 and saves roughly Rs 2,13,700 of interest.
The effect is largest early in the loan, when the balance and the interest on it are highest. A prepayment in year one removes far more future interest than the same amount paid in year eight, which is worth knowing before a bonus lands.
What this does not promise
The EMI here uses the reducing-balance math every bank uses, but a real loan can carry a processing fee, insurance, or a floating rate that moves with the market, none of which are in the monthly figure. Prepayment charges, where a lender levies them, are not modelled either. Loan approval depends on your income, credit history and the lender's rules, so a comfortable EMI on screen is not an offer. This is a planning tool, not financial advice, so confirm the exact terms with your bank and, for a large loan, a qualified adviser.
Frequently asked questions
What is an EMI calculator? An EMI calculator works out the fixed monthly installment on a loan from the amount, the interest rate and the tenure, using the reducing-balance formula that Indian banks apply. A Rs 10,00,000 loan at 9% for 10 years has an EMI of Rs 12,668, with Rs 5,20,160 of total interest.
What is the EMI formula? The EMI formula is EMI = P times r times (1 + r) to the power n, divided by (1 + r) to the power n minus 1, where P is the loan amount, r is the monthly rate (the annual rate divided by 12 and by 100), and n is the number of months. The interest each month is charged on the balance still outstanding, which is why it is called the reducing-balance method.
What is the difference between a flat rate and a reducing rate? A reducing-rate loan charges interest only on the outstanding balance, which falls every month, while a flat-rate loan charges interest on the full amount for the whole tenure. A flat rate therefore costs far more: on Rs 10,00,000 at 9% for 10 years the reducing EMI is Rs 12,668 against a flat EMI of Rs 15,833, and a 12% flat rate works out close to a 21% reducing rate.
How does prepaying a loan save money? Because interest is charged on the outstanding balance, paying extra reduces that balance and every future interest charge on it, so the loan finishes sooner. Adding Rs 5,000 a month to the EMI on a Rs 10,00,000 loan at 9% clears it in about 74 months instead of 120 and saves roughly Rs 2,13,700 of interest.
How is the EMI split between principal and interest? Each EMI is the same, but its make-up changes: early on most of it is interest because the balance is large, and later most of it is principal as the balance shrinks. The year-by-year schedule above shows this split and the balance left at the end of each year.
Does this work for home, car and personal loans? Yes, the reducing-balance EMI math is the same for a home loan, car loan, personal loan, two-wheeler loan or gold loan; only the rate and tenure differ. Enter your loan amount, the rate your bank quotes, and the tenure, and the EMI and schedule apply to any of them.
What EMI can I afford? Lenders often look for the total of your EMIs to stay within about 40% to 50% of your monthly income, though the exact limit is theirs to set. This calculator shows the EMI for a given loan; whether it fits your budget depends on your income and other commitments, so treat the figure as a planning input.