Key points
- A flat rate charges interest on the full original loan every year, even as you repay it.
- A flat rate is roughly equal to 1.7–1.9 times the same number as a reducing-balance rate.
- A 10% flat rate on a 5-year loan is equivalent to about 17.3% reducing.
- Compare loans using the APR in the Key Fact Statement, never the flat rate.
Two ways to charge interest
On a reducing-balance loan — the standard for bank home, car and personal loans — interest each month is charged only on what you still owe. As you repay, the interest falls.
On a flat-rate loan, interest is worked out once on the original amount for the whole tenure: interest = loan × flat rate × years. That total is added to the loan and divided by the number of months to get the EMI. You pay interest on money you have already repaid.
Example: ₹5 lakh for 5 years
| 10% flat | 10% reducing | |
|---|---|---|
| Monthly EMI | ₹12,500 | ₹10,624 |
| Total interest | ₹2,50,000 | ₹1,37,411 |
| Equivalent reducing rate | ≈ 17.3% | 10% |
The flat-rate loan costs over ₹1.1 lakh more in interest. Its real cost — the reducing-balance rate that produces the same EMI — is about 17.3% a year.
Flat rate to reducing rate: quick reference
| Flat rate | 3-year loan | 5-year loan |
|---|---|---|
| 6% flat | ≈ 11.1% | ≈ 10.9% |
| 8% flat | ≈ 14.5% | ≈ 14.1% |
| 10% flat | ≈ 17.9% | ≈ 17.3% |
| 12% flat | ≈ 21.2% | ≈ 20.3% |
A rough rule: multiply a flat rate by about 1.8 to estimate the true rate. The flat vs reducing rate calculator gives the exact figure for any rate and tenure.
Where flat rates still appear
- Two-wheeler and used-car finance arranged at dealerships.
- Consumer-durable loans for phones, appliances and electronics.
- Some personal loans from smaller lenders and microfinance loans.
- Gold loans and “low interest” offers in advertisements.
Since October 2024, RBI rules require lenders to give every retail borrower a Key Fact Statement showing the annual percentage rate (APR), which is calculated on a reducing-balance basis and includes fees. Ask for it, and compare that number.
Converting a flat rate yourself
You can work out a flat-rate loan’s true cost in three steps:
- Total interest = loan × flat rate × years. For ₹5 lakh at 10% flat for 5 years: ₹2,50,000.
- EMI = (loan + total interest) ÷ months = ₹7,50,000 ÷ 60 = ₹12,500.
- Find the reducing-balance rate that gives the same EMI on ₹5 lakh over 60 months — about 17.3%. In a spreadsheet: =RATE(60, -12500, 500000) × 12.
The flat vs reducing rate calculator does the conversion instantly and shows the year-by-year split of each EMI.
Reading loan advertisements
- “Interest from 0.8% per month” is usually a flat monthly rate — close to 17%–18% a year on a reducing basis.
- “Zero-interest EMI” schemes usually recover the cost through a processing fee, a higher product price or a lost cash discount.
- “Low EMI” offers often stretch the tenure or add a balloon payment at the end.
- If the advertisement or dealer cannot tell you the APR, ask for the Key Fact Statement before you sign anything.
Frequently asked questions
Is a flat rate ever cheaper?
Not when compared at the same headline number. A flat rate always costs more than the same number as a reducing rate, because interest is charged on money already repaid. A flat rate is only cheaper if its number is low enough — roughly under 55% of the reducing rate you are comparing it with.
Do prepayments help on a flat-rate loan?
Often less than you expect. Some flat-rate lenders calculate foreclosure using the “rule of 78” or charge the remaining flat interest, so check how a prepayment would be treated before you sign.
Do banks use flat rates for home loans?
No. Home loans from banks and housing finance companies are always on a reducing-balance basis. Flat rates appear mainly in dealer and consumer finance.