How Is EMI Calculated? The Formula Explained
3 min readUpdated June 7, 2026
EMI stands for Equated Monthly Installment — the fixed amount you pay your lender every month until a loan is fully repaid. It is the standard way home loans, car loans, and personal loans are paid back: one predictable payment, the same size each month, for the whole term.
The key idea is that every EMI is split into two parts: the interest owed on the outstanding balance, and a chunk of the principal you originally borrowed. Early on most of the payment goes to interest; later, as the balance shrinks, more of it goes to principal. The total stays constant, but the mix shifts over time.
The EMI formula
EMI is calculated with a single formula: EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1). It looks dense, but each term is simple.
P is the principal — the amount you actually borrow. r is the monthly interest rate, which you get by taking the annual interest rate and dividing it by 12 and then by 100 (so 8% per year becomes 0.08 ÷ 12 ≈ 0.006667 per month). n is the number of monthly installments — the loan tenure in months, so a 5-year loan is 60 installments.
In plain English, the formula spreads the principal plus all the compound interest evenly across every month, so each payment is identical. The (1 + r)^n term is what compounds the interest over the full term, and dividing by ((1 + r)^n − 1) is what converts that compounded total into one level monthly figure.
A worked example
Suppose you borrow $100,000 at 8% per year for 5 years. First convert the rate: 8% annual becomes a monthly rate of 0.08 ÷ 12 ≈ 0.006667. The tenure of 5 years becomes n = 60 monthly installments.
Plugging P = 100,000, r ≈ 0.006667, and n = 60 into the formula gives an EMI of about $2,028 per month. That is the fixed amount you would pay every month for five years.
To see the cost of borrowing, multiply the EMI by the number of payments: $2,028 × 60 ≈ $121,658 total payable. Subtract the original $100,000 principal and you are left with about $21,658 in total interest. So borrowing $100,000 on these terms costs roughly $21,658 over the life of the loan.
How rate and tenure affect your EMI and interest
Two levers shape every EMI: the interest rate and the tenure. They pull in different directions, which is why the same loan amount can feel very different depending on how it is structured.
A longer tenure lowers your monthly EMI because the principal is spread across more payments — easier on a monthly budget. But because you owe interest for more months, the total interest you pay goes up. A shorter tenure does the opposite: a higher EMI, but less total interest.
A higher interest rate raises both numbers at once. Each month's interest charge is larger, so the EMI climbs and the total interest paid climbs with it. When comparing loan offers, look at the total interest over the full term, not just the monthly payment, so a low EMI from a long tenure does not hide a much larger overall cost.
Fixed vs reducing balance
The standard EMI formula above uses a reducing-balance method: interest each month is charged only on the outstanding principal, which falls as you repay. This is the fair and most common approach for home, car, and personal loans.
Some lenders quote a flat-rate (fixed) scheme instead, where interest is charged on the full original principal for the entire term regardless of how much you have already paid back. A flat rate looks lower than an equivalent reducing rate but usually costs more, so always confirm which method a quoted rate uses before comparing offers.
Frequently asked questions
What is EMI?+
EMI stands for Equated Monthly Installment — a fixed monthly payment that repays a loan over its term. Each payment covers both interest on the outstanding balance and part of the principal.
What is the EMI formula?+
EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), where P is the principal, r is the monthly interest rate (annual rate ÷ 12 ÷ 100), and n is the number of monthly installments.
Does a longer tenure cost more?+
Yes. A longer tenure lowers your monthly EMI but increases the total interest paid, because you owe interest for more months. A shorter tenure raises the EMI but reduces total interest.
Is the EMI the same every month for a fixed-rate loan?+
Yes. For a fixed-rate loan the EMI stays constant for the whole term. What changes is the split inside it: more interest early on and more principal later as the balance shrinks.