Flat vs Reducing Rate Calculator

Enter the loan amount, the flat rate you were quoted and the tenure. The calculator finds the reducing-balance rate that gives the same EMI, so you can compare the quote with a bank loan quoted the normal way.

How to use the calculator

1. Loan amount: the amount financed, which is the price minus your down payment, plus any processing fee or insurance added to the loan.
2. Flat interest rate: the yearly rate the dealer or lender quoted.
3. Tenure: the number of years, up to 10.

The result shows the equivalent reducing-balance rate, the EMI, the total interest at the flat rate, what the interest would be at the same rate on a reducing balance, and the extra cost of the flat method.

How a flat rate works

With a flat rate, interest is worked out once on the full loan amount for the whole tenure:

Interest = loan amount × flat rate × years

That interest is added to the loan, and the total is divided by the number of months to give the EMI.

With the defaults, ₹5 lakh at a 10% flat rate for 3 years:

• Interest: ₹5,00,000 × 10% × 3 = ₹1,50,000
• Total to repay: ₹6,50,000
• EMI: ₹6,50,000 ÷ 36 = ₹18,056

The problem is that you repay part of the principal with every EMI, but interest was charged as if you owed the full ₹5 lakh for all three years. On average you owe only about half of it over the tenure, so the real cost is close to double the quoted rate.

How the reducing rate is found

A reducing-balance rate charges interest each month only on what you still owe, which is how banks price home loans and most personal and car loans. The calculator finds the reducing rate that produces the same EMI. In the example, an EMI of ₹18,056 for 36 months on ₹5 lakh corresponds to a reducing rate of about 17.92%.

So a “10% flat” loan costs the same as a loan at about 17.9% from a bank. At a genuine 10% reducing rate, the same loan would cost about ₹80,809 in interest instead of ₹1,50,000, saving ₹69,191.

Typical conversions

Flat rate	Tenure	Equivalent reducing rate	Interest on ₹5 lakh
8%	3 years	14.55%	₹1,20,000
10%	3 years	17.92%	₹1,50,000
10%	5 years	17.27%	₹2,50,000
12%	3 years	21.20%	₹1,80,000

For tenures of two to five years, the reducing rate is a little under double the flat rate. The longer the tenure, the more total interest you pay, even though the equivalent rate barely moves.

Checking the conversion by hand

You can confirm the result without the calculator. Take the EMI from the flat-rate quote, ₹18,056 in the example, and put the loan amount, the tenure and a guessed rate into the EMI calculator. At 17% the EMI comes out a little below ₹18,056, and at 18% a little above. The rate where the two EMIs match is the reducing rate, about 17.92%. This calculator does the same search automatically, testing rates until the EMIs agree to the paisa.

Why the gap is so large

Think of the balance over the life of the loan. On a reducing-balance loan of ₹5 lakh over three years, the balance starts at ₹5 lakh and falls to zero, so on average you owe a little more than half of it. A flat rate ignores that and charges interest on the full ₹5 lakh every month. Paying 10% on twice the money you actually have on average is roughly the same as paying close to 20% on what you do owe. The exact figure is a little lower, 17.92%, because the balance falls slowly in the early months, when more of each EMI is interest.

Where flat rates are still quoted

• Two-wheeler loans at dealerships.
• Consumer durable loans for phones, TVs and appliances.
• Some used-car loans and loans from smaller NBFCs.
• Some microfinance and small-business loans.
• Some gold loan and vehicle loan schemes in rural areas.

The salesperson may quote only the flat rate or only the EMI, because both look better than the reducing rate.

A two-wheeler example

A bike costs ₹1,20,000 on-road. You pay ₹20,000 down and the dealer offers to finance ₹1 lakh at a “9% flat rate” for 2 years. The EMI is ₹4,917 and the total interest ₹18,000.

Enter ₹1,00,000, 9% and 2 years. The reducing rate comes out at about 16.43%. A bank two-wheeler or personal loan at 12% reducing for 2 years would cost about ₹12,976 in interest, about ₹5,000 less. Many dealers also add a processing fee and file charges, which push the real cost higher still. Ask for the APR in the key fact statement and compare it with what your bank offers.

Small-business and weekly repayment loans

Some business loans and microfinance loans are repaid weekly or fortnightly rather than monthly, and are often quoted at a flat rate. Because repayments start sooner and come more often, the average balance falls even faster, so the real rate is higher than the monthly conversion here suggests. Treat the result as a lower limit for such loans. Business loans quoted as a total repayment amount, such as “repay ₹1.25 lakh on ₹1 lakh over a year”, can be converted too: the extra ₹25,000 over one year is a 25% flat rate, which this calculator turns into a reducing rate of about 43%.

Zero-cost EMI offers

“No cost EMI” offers on phones and appliances usually work by giving you a discount equal to the interest, or by building the interest into the price. Sometimes a processing fee is still charged, and GST is charged on the interest component. The cleanest test is to compare the total you will pay with the price if you paid in full at a shop that offers a cash discount. If they are the same, the offer is genuinely interest-free.

What RBI requires lenders to disclose

RBI requires regulated lenders to give borrowers a key fact statement for retail and MSME loans, showing the annual percentage rate (APR) that includes interest and all fees. Ask for the key fact statement before you sign, and compare the APR there with the reducing rate from this calculator. If the APR is much higher still, there are fees you have not been told about.

Paying a flat-rate loan off early

With a reducing-balance loan, prepaying saves the interest for the months you no longer owe money. With a flat-rate loan, the interest was fixed upfront, so the saving depends on how the lender calculates the payoff. Some lenders give little rebate, and fixed-rate loans can carry foreclosure charges. Ask for the foreclosure terms in writing before signing.

How to compare offers

1. Convert every flat-rate quote to a reducing rate here.
2. Compare offers at the same loan amount and tenure.
3. Add processing fees, file charges and compulsory insurance to the loan amount.
4. Check the EMI and total interest in the EMI calculator using the reducing rate.

For the full EMI-by-EMI picture of a reducing loan, use the loan amortization schedule. To see whether your income supports a loan, try the loan eligibility calculator.

The conversion runs in your browser, and the figures you enter are not sent anywhere.

Frequently asked questions

What is the difference between a flat rate and a reducing rate?

A flat rate charges interest on the original loan amount for the whole tenure. A reducing rate charges interest each month only on the outstanding balance. Because you repay principal every month, a flat rate costs much more than the same reducing rate, roughly 1.7 to 1.9 times for typical tenures.

How do I convert a flat rate to a reducing rate?

Enter the loan amount, flat rate and tenure in the calculator. It finds the reducing rate with the same EMI. As a rough guide, multiply the flat rate by about 1.8 for loans of two to five years: 10% flat is about 17.9% reducing over three years.

Is a 7% flat rate cheaper than an 11% reducing rate?

Usually not. Over three years, a 7% flat rate is about a 12.8% reducing rate, so the 11% reducing loan is cheaper. Over one year, 7% flat is about 12.7% reducing. Always convert before comparing, and include fees on both sides.

Why do lenders still quote flat rates?

Flat rates are simple to calculate and look lower. They are common in two-wheeler, consumer durable and small-business lending, where buyers often compare offers by EMI alone. RBI expects lenders to disclose the annual percentage rate so borrowers can see the real cost.

Does a longer tenure make a flat-rate loan cheaper?

No. The equivalent reducing rate falls only slightly with a longer tenure, but total interest rises in line with the years. On ₹5 lakh at 10% flat, interest is ₹1.5 lakh over three years and ₹2.5 lakh over five.

Is flat rate the same as add-on rate?

Yes. Add-on rate is the term used in the United States for the same method: interest calculated on the original amount for the full tenure and added to the loan before splitting it into EMIs.