A car dealer says the loan is "just 6%". A bank down the road says 11%. The dealer sounds cheaper. Often, it is not. The two numbers are measured in different ways. One is a flat rate. The other is a reducing balance rate. This guide shows how each works, how to convert one into the other, and what to ask before you sign.
What is a flat interest rate?
With a flat rate, interest is worked out on the full loan amount for the whole loan period. It does not matter that you repay part of the loan every month.
The sum is simple:
- Total interest = loan amount × flat rate × number of years
- EMI = (loan amount + total interest) ÷ number of months
EMI means equated monthly instalment. It is the fixed amount you pay every month until the loan ends.
What is a reducing balance rate?
With a reducing balance rate, interest is charged only on the amount you still owe. Each EMI pays some interest and some principal (the borrowed amount). As the principal falls, the interest part of each EMI falls too. Home loans and most bank loans in India work this way.
The EMI comes from a standard formula:
EMI = P × r × (1 + r)^n ÷ ((1 + r)^n − 1)
Here P is the loan amount, r is the monthly rate (annual rate ÷ 12 ÷ 100), and n is the number of months. You do not need to do this by hand. Our EMI calculator does it for you.
Why does a flat rate look cheaper than it is?
Take a car loan of ₹5,00,000 for 3 years (36 months).
| Item | 6% flat | 6% reducing |
|---|---|---|
| Total interest | ₹90,000 | ₹47,595 |
| Total repaid | ₹5,90,000 | ₹5,47,595 |
| Monthly EMI | ₹16,389 | ₹15,211 |
At 6% flat, interest is ₹5,00,000 × 6% × 3 = ₹90,000. Add the loan and divide by 36: the EMI is ₹16,389.
At 6% reducing, the formula gives an EMI of ₹15,211. Total interest is ₹47,595. That is ₹42,405 less than the flat-rate loan.
Why the gap? Each EMI repays part of the loan. If the principal is repaid in equal parts, after 24 of the 36 EMIs you have repaid ₹3,33,333 and owe only ₹1,66,667. Yet the flat rate still charges interest as if you owed the full ₹5,00,000 in every month of the loan.
How do you convert a flat rate to a reducing rate?
Ask one question: what reducing rate gives the same EMI? For the loan above, the EMI of ₹16,389 over 36 months matches a reducing rate of about 11.08% a year. So "6% flat" costs about the same as an 11.08% bank loan, before fees.
The answer depends on the flat rate and the tenure, not on the loan amount. We worked these out with the EMI formula:
| Flat rate | 1 year | 2 years | 3 years | 5 years | 7 years |
|---|---|---|---|---|---|
| 5% | 9.10% | 9.32% | 9.31% | 9.15% | 8.97% |
| 6% | 10.90% | 11.13% | 11.08% | 10.85% | 10.58% |
| 7% | 12.68% | 12.91% | 12.83% | 12.50% | 12.16% |
| 8% | 14.45% | 14.68% | 14.55% | 14.13% | 13.69% |
| 10% | 17.97% | 18.16% | 17.92% | 17.27% | 16.66% |
A quick rule: for loans of 1 to 7 years, the reducing rate is roughly 1.7 to 1.9 times the flat rate. Use the table or our calculator for the exact figure.
Where are flat rates usually quoted?
You may hear flat rates for:
- Car and used-car loans arranged at the showroom
- Two-wheeler loans
- Consumer durable loans for phones, TVs and appliances
- Some personal and small business loans, often from smaller lenders
A two-wheeler example: ₹1,00,000 for 2 years at 9% flat. Interest is ₹1,00,000 × 9% × 2 = ₹18,000. The EMI is ₹4,917. The matching reducing rate is about 16.43%.
What does the Key Facts Statement show?
The RBI (Reserve Bank of India) issued rules in April 2024 on the Key Facts Statement, or KFS. Banks and NBFCs (non-banking finance companies) must give a KFS for retail and MSME term loans sanctioned on or after 1 October 2024. The KFS must show the Annual Percentage Rate (APR). RBI defines APR as the yearly cost of credit, including the interest rate and all other charges the lender levies.
Two points help you here:
- The APR is an annual, all-in figure. It lets you compare a "flat" quote with a bank's reducing rate on the same footing.
- Fees not mentioned in the KFS cannot be charged later without your explicit consent.
The KFS rule does not cover credit card dues. Read the full circular on rbi.org.in.
What should you ask the dealer or lender?
- Is this rate flat or reducing? Ask them to write it down.
- What is the APR in the KFS? Compare APRs, not headline rates.
- What are the processing fee, documentation charges and insurance? These add to your cost.
- How many advance EMIs do I pay? Paying EMIs upfront means you borrow less than the stated amount, which raises the real rate.
- Is the rate fixed or floating? A flat-rate loan is usually fixed. This matters if you want to close it early.
- What are the foreclosure charges? Foreclosure means closing the loan before its end date.
Already have a flat-rate loan? Can you lower its cost?
Possibly. Your options:
- Prepay or close it early. Check your loan agreement and KFS for charges. Under RBI's prepayment directions, from 1 January 2026, lenders cannot charge prepayment fees on floating-rate loans taken by individuals for non-business purposes, if sanctioned or renewed on or after that date. For fixed-rate loans, charges follow the lender's own policy, as disclosed to you.
- Refinance with a reducing-rate loan. If a bank offers a lower APR, the saving may cover the foreclosure charge. Do the sum first.
- Ask how the payoff amount is worked out. On a flat-rate loan, ask the lender to show how much principal and interest remain.
Lenders decide whether to offer a better deal. Nothing is guaranteed, but asking costs nothing.
Do it in 10 minutes, free
Open the Flat vs Reducing Rate calculator on LowerMyEMI. Enter the flat rate and tenure the dealer quoted. It shows the true reducing rate and the total interest. You can export the result to Excel or PDF. If you already have a loan, type in its details. LowerMyEMI writes one email per lender asking for a lower rate. You send them from your own email. It is free. We are not a lender or loan agent, and we take no money from lenders.