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How Your Loan EMI Is Calculated, and Two Ways to Pay Far Less Interest
Quick Work Studio · 2026-10-01
An EMI, equated monthly instalment, stays the same every month, but what it pays for changes dramatically over the life of a loan. Understanding that is the key to paying less.
The formula
EMI = P × r × (1 + r)n ÷ ((1 + r)n − 1), where P is the loan amount, r is the monthly interest rate (the annual rate ÷ 12 ÷ 100) and n is the number of months. You don't need to work it out by hand, but it shows that the EMI depends on just three things: amount, rate and tenure.
A worked example
Take a home loan of ₹20 lakh at 8.5% for 20 years (240 months). The EMI is about ₹17,356. Over 240 months, you repay about ₹41.66 lakh, so the interest alone is about ₹21.66 lakh, more than the amount you borrowed.
Why early EMIs are mostly interest
Interest is charged on the outstanding balance. In the first month, the balance is the full ₹20 lakh, so about ₹14,167 of your ₹17,356 EMI is interest and only about ₹3,190 reduces the loan. As the balance falls, the interest part shrinks and the principal part grows, until the last EMIs are almost entirely principal. This is why money paid towards the loan early has such a big effect.
Way 1: Choose a shorter tenure if you can
The same ₹20 lakh loan over 15 years has an EMI of about ₹19,695, roughly ₹2,340 more per month. But the total interest falls to about ₹15.45 lakh, saving around ₹6.2 lakh compared with 20 years.
Way 2: Prepay or increase your EMI
- A one-time prepayment of ₹1 lakh at the start of the loan (keeping the same EMI) closes it about 28 months early and saves about ₹3.9 lakh of interest.
- Paying just ₹2,000 extra every month closes the loan in about 187 months instead of 240, over four years early, and saves about ₹5.6 lakh.
For floating-rate home loans taken by individuals, Indian banks generally aren't allowed to charge prepayment penalties, but always confirm your loan's terms.
Beware of "flat" interest rates
Some personal and vehicle loans quote a flat rate, where interest is charged on the original amount for the whole term even as you repay it. A 3-year loan at 10% flat costs about the same as a normal reducing-balance loan at nearly 18%. Always compare loans using the reducing-balance rate or the annual percentage rate.
What the EMI doesn't include
Processing fees, insurance, and charges for late payments are extra. Ask for the total cost of the loan, not just the EMI, before you sign.
Try it: the Loan / EMI Calculator shows your EMI, total interest and total repayment. Use the Simple Interest Calculator to see how a flat rate compares.