If you've ever compared two loan offers with the "same" interest rate and wondered why one EMI is so much higher than the other, the answer almost always comes down to one thing: how the interest is calculated, not just the rate itself. There are two common methods lenders use — reducing balance and flat rate — and the real cost difference between them can be shockingly large.
In the flat rate method, interest is calculated on the full original loan amount for the entire tenure — even though you're paying it down every month. Take a ₹5,00,000 loan at 10% flat, over 5 years: interest works out to ₹5,00,000 × 10% × 5 = ₹2,50,000, making the total payable ₹7,50,000, or an EMI of ₹12,500.
Here, interest is calculated only on the outstanding principal — the amount you actually still owe, which shrinks every month as you make payments. On the same ₹5,00,000 loan at 10% reducing, the EMI works out to roughly ₹10,624/month — noticeably lower than the flat-rate EMI of ₹12,500, even though both were quoted at "10%."
In the flat method, you effectively pay interest on money you've already returned to the lender. Over the full tenure, this can push the real effective interest rate to almost double the advertised rate.
| Flat Rate (10%) | Reducing Balance (10%) | |
|---|---|---|
| EMI | ₹12,500 | ~₹10,624 |
| Total interest paid | ₹2,50,000 | ~₹1,37,000 |
| Effective annual rate | ~18–19% | 10% |
Home loans, most bank personal loans, and car loans: reducing balance — RBI-regulated banks are required to disclose this clearly. Some NBFC personal loans, gold loans, and consumer durable/EMI card schemes: flat rate, often without making the distinction obvious.
A "10% flat" loan and a "10% reducing balance" loan are not the same product — not even close. Run your loan amount through the calculator to see the real EMI and total interest under each method before you decide.
Open the EMI Calculator