How to Calculate EMI in 2027: Formula, Worked Example & Amortisation

Hope Hai — Tue, 10 Nov 2026 04:56:05 +0000

Short answer: EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12), and n is the number of monthly payments. On a $250,000 home loan at 8.5% over 20 years, that works out to $2,169.56 a month — and $270,693.94 of interest over the life of the loan, more than the amount borrowed. The payment stays the same every month, but what it pays for changes: early payments are mostly interest, later ones mostly principal.

EMI stands for Equated Monthly Instalment: the fixed amount you pay your lender every month until the loan is fully repaid. "Equated" is the key word — the payment is equal every month, which is convenient for budgeting but hides how the money is split. In the first month of a long loan, roughly four-fifths of your payment is interest and only a fifth repays the loan itself. By the final month, the split has flipped almost entirely. Once you can calculate an EMI yourself, you can check any loan offer in a minute, compare tenures honestly, and see exactly what an extra payment is worth before you commit to it.

The 60-Second Method

Three steps, in order:

Find your monthly rate: divide the annual rate by 12. At 9% a year, that is 0.09 ÷ 12 = 0.0075 a month. Never use the annual rate directly in the formula — that is the most common mistake, and it roughly multiplies the answer by twelve.
Count the payments: multiply the years by 12. A 15-year loan is 180 monthly payments.
Apply the formula: EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1). With P = $120,000, r = 0.0075 and n = 180, the EMI is $1,217.12 a month.

That is the whole calculation. The (1 + r)^n term is compounding at work: it is the factor by which the loan would grow if you made no payments at all, and the formula uses it to find the fixed payment that exactly clears the debt — interest and principal together — by the final month. To save doing it by hand, try the free EMI calculator — it runs the same formula instantly and shows the month-by-month split, which is where the real insight lives.

The Formula, Explained

EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1)

P — principal: the amount you actually borrow. Not the price of the house or the car — the loan sanctioned after your deposit or down payment.
r — monthly rate: the annual interest rate ÷ 12. A 10% annual rate is 0.10 ÷ 12 = 0.008333 a month.
n — number of payments: the tenure in months. Five years is 60, twenty years is 240.

Two things about the formula are worth understanding rather than memorising. First, it assumes a reducing balance: interest each month is charged only on the amount you still owe, so the interest part of every payment falls as the balance falls. That is how almost every bank loan, mortgage and car loan works. Second, it assumes a fixed rate for the whole tenure. If your rate changes — as it does when a fixed-rate mortgage period ends — the EMI is recalculated on the remaining balance at the new rate. As a sanity check, the formula gives $8,791.59 a month for a $100,000 loan at 10% over 12 months.

Worked Example 1: A $250,000 Home Loan

Take a home loan of $250,000 at 8.5% a year for 20 years. The monthly rate is 0.085 ÷ 12 = 0.007083, and there are 240 payments. Plugging those into the formula:

EMI = 250,000 × 0.007083 × (1.007083)^240 ÷ ((1.007083)^240 − 1) = $2,169.56 a month.

Over 240 months you pay $520,693.94 in total — $250,000 of principal and $270,693.94 of interest. The interest costs more than the loan itself. Here is how the split changes over time:

Month	Interest part	Principal part	Balance left
Month 1	$1,770.83	$398.72	$249,601.28
Month 2	$1,768.01	$401.55	$249,199.73
Month 12	$1,738.64	$430.92	$245,024.43
Month 240 (last)	$15.26	$2,154.30	$0.00

After a full year of payments totalling $26,034.72, you have paid $21,059.11 in interest and only $4,975.58 off the balance — the loan has barely moved. That is the part of a long loan that surprises most borrowers: the balance falls slowly at first because the interest is charged on nearly the full amount. The principal part does not overtake the interest part until month 143, almost 12 years in. By the final month, the split has reversed completely: $15.26 of interest and $2,154.30 of principal.

Worked Example 2: A Car Loan and a Personal Loan

The same formula covers every loan type — only the numbers change. A $25,000 car loan at 9.25% over 5 years (60 months) gives a monthly rate of 0.007708 and an EMI of $522.00. The first payment is $192.71 of interest and $329.29 of principal, leaving $24,670.71; the last is $3.99 of interest and $518.00 of principal. Total interest: $6,319.85 on top of the $25,000 borrowed.

A $10,000 personal loan at 12% over 3 years gives an EMI of $332.14 a month, with total interest of $1,957.15. Notice how the shorter tenure keeps the interest down even at a higher rate: 3 years at 12% costs $1,957 in interest on $10,000, while 5 years at 9.25% costs $6,320 on $25,000. Rate matters, but tenure matters more.

What Does EMI Look Like at Different Rates and Tenures?

This table shows the monthly EMI on every $100,000 borrowed, so you can scale it to any loan — double the figures for $200,000, halve them for $50,000:

Tenure	7% annual	8.5% annual	10% annual
10 years	$1,161.08 (interest $39,330)	$1,239.86 (interest $48,783)	$1,321.51 (interest $58,581)
15 years	$898.83 (interest $61,789)	$984.74 (interest $77,253)	$1,074.61 (interest $93,429)
20 years	$775.30 (interest $86,072)	$867.82 (interest $108,278)	$965.02 (interest $131,605)
30 years	$665.30 (interest $139,509)	$768.91 (interest $176,809)	$877.57 (interest $215,926)

Two patterns jump out. Going from 7% to 10% adds roughly $200 a month per $100,000 on a 10-year loan — rate differences are worth negotiating. And stretching the tenure from 10 to 30 years only cuts the payment by about 43%, while the total interest more than triples. A useful rule of thumb: on a 20-year loan at 8–9%, the EMI runs at roughly 0.85–0.9% of the principal each month — the $250,000 example above is 0.87%.

The Tenure Trap: A Lower EMI Can Cost You a Fortune

Lenders sell longer tenures on the lower monthly payment. Here is what that lower payment actually costs on the $250,000 loan at 8.5%:

Tenure	Monthly EMI	Total interest
10 years	$3,099.64	$121,957.07
15 years	$2,461.85	$193,132.80
20 years	$2,169.56	$270,693.94
25 years	$2,013.07	$353,920.31
30 years	$1,922.28	$442,022.14

Stretching from 20 to 30 years saves $247.28 a month — but costs $171,328.20 more in interest, and you pay for an extra decade. The right tenure is the shortest one whose EMI you can afford comfortably, not the longest one the lender offers. If the 10-year EMI is out of reach, the 15-year loan still saves $77,561.14 of interest versus the 20-year one. Compare offers by total interest, not by monthly payment: two loans with the same EMI can have very different total costs once the tenure differs.

The Flat-Rate Trap: Not Every "EMI" Uses This Formula

Most bank loans use the reducing-balance method above. Some lenders — especially on personal loans and vehicle finance in some markets — quote a flat rate instead: interest is charged on the full principal for the whole tenure, even as you repay it. On the same $250,000 at 8.5% over 20 years, a flat rate gives a monthly payment of $2,812.50 — $642.94 a month more than the reducing-balance EMI of $2,169.56 — and total interest of $425,000 instead of $270,693.94.

Before signing, ask one question: "Is the interest calculated on a reducing balance?" If the answer is flat-rate, the quoted rate is not comparable to a bank's rate at all — an 8.5% flat rate behaves roughly like a 15–16% reducing-balance rate on a long loan. The loan agreement should state the method; if it does not, treat that as a warning sign.

Extra Payments Pay Off Faster Than You Think

Because early payments are mostly interest, anything extra you pay early in the loan cuts the balance — and every future month's interest with it. On the $250,000 example, paying just $100 extra a month clears the loan in 215 months instead of 240: 25 months early, with total interest of $237,229.32 instead of $270,693.94 — a saving of $33,464.62 for $100 a month. The effect is strongest in the first years, when the balance is highest and each extra dollar avoids the most future interest.

Check for a prepayment penalty first: some fixed-rate loans charge a fee for paying extra, though many lenders allow a set amount of overpayment each year free of charge.

Common Mistakes

Using the annual rate as the monthly rate. The formula needs r = annual rate ÷ 12. Using 8.5% instead of 0.7083% a month produces a nonsense payment roughly twelve times too large — and the reverse error, dividing by 100 twice, produces one far too small.
Forgetting the tenure is in months. n is 240 for a 20-year loan, not 20. Using years in the exponent breaks the formula completely.
Comparing EMIs across different tenures. A lower EMI on a longer loan is not a cheaper loan — it is almost always a much more expensive one, as the tenure table above shows. Compare total interest, or compare EMIs only at the same tenure.
Assuming the EMI is the whole monthly cost. Standard EMI calculators show principal plus interest only. A mortgage also needs taxes, insurance and possibly PMI; a car loan may have fees on top. Add those separately when you budget, or the EMI will understate what leaves your account each month.
Treating a flat-rate quote like a reducing-balance rate. An 8.5% flat rate costs far more than an 8.5% reducing-balance rate. Confirm the method before you compare rates between lenders.

UK Note: Monthly Payments, Fixed Rates and Overpayments

The maths is identical in the UK — a repayment mortgage's monthly payment is an EMI by another name, calculated on the same reducing-balance formula. The differences are in the labels and the deal structure. UK mortgages are usually sold with an initial fixed-rate period — two or five years is common — after which the rate moves to the lender's standard variable rate and the monthly payment is recalculated on the remaining balance. A rate rise at that point raises the payment, so the EMI you agree today is only guaranteed for the fixed period.

On overpayments, many UK lenders let you pay up to 10% of the outstanding balance each year without an early-repayment charge — check your mortgage offer for the exact figure, because it varies. The same extra-payment maths applies: overpaying early in a 25-year mortgage saves far more interest than overpaying late, for exactly the reasons the amortisation table shows. And one UK-specific point: the monthly payment on a repayment mortgage always includes principal, unlike an interest-only mortgage, where the payment covers interest alone and the original loan is still owed in full at the end.

FAQs

How do I calculate EMI?

Use EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), where P is the loan amount, r is the annual rate ÷ 12, and n is the tenure in months. A $250,000 loan at 8.5% over 20 years gives an EMI of $2,169.56 a month.

What is the EMI on a $250,000 loan at 8.5% for 20 years?

$2,169.56 a month. You repay $520,693.94 in total — $250,000 of principal and $270,693.94 of interest.

Does a longer tenure lower my EMI?

Yes, but it raises the total interest sharply. On $250,000 at 8.5%, stretching from 20 to 30 years cuts the EMI from $2,169.56 to $1,922.28 — and adds $171,328.20 of interest. Take the shortest tenure whose EMI you can afford comfortably.

Why is my first EMI mostly interest?

Because interest is charged on the balance you still owe, which is at its highest in month one. On the $250,000 example, the first payment is $1,770.83 of interest and only $398.72 of principal. The principal part does not overtake the interest part until month 143.

How much do I save by paying extra on my EMI?

A lot, especially early. An extra $100 a month on the $250,000 example clears the loan 25 months early and saves $33,464.62 in interest. Check for a prepayment penalty before you start.

Try It Yourself

Run your own loan through the free EMI calculator — enter the amount, rate and tenure, add an extra monthly payment, and watch the amortisation table and the interest saved update instantly.

This article is general information, not financial advice: your loan agreement sets the exact rate, method and fees for your loan, and if a payment is unmanageable, speak to your lender before you miss it — most will discuss a revised plan. Adapted from the original article on Sawalify.

DEV Community: Hope Hai