Flat vs Reducing Interest Rate: Why a Flat 10% Is Really 18%

The man at the bike showroom says the loan is "only 9% interest". The bank's personal loan is 12%. Most people take the 9% without thinking twice, and that is often a mistake, because the two numbers aren't measured the same way. The showroom's 9% is usually a flat rate. The bank's 12% is a reducing balance rate. On ₹1 lakh for two years, that "cheaper" 9% flat costs about ₹5,000 more than the 12% loan.

You can't compare those two numbers until you convert one into the other. Once you know how, that takes about two minutes, and since October 2024 RBI makes regulated lenders do the conversion for you on paper. Here is how the two methods work, what the gap is in rupees, and how to check an offer at the counter.

Same "10%", two very different loans

With a flat rate, interest is worked out on the full loan amount for the full tenure, as if you never paid back a single rupee. Say you borrow ₹1 lakh at a flat 10% for 3 years:

• Interest = ₹1,00,000 × 10% × 3 = ₹30,000
• Total to repay = ₹1,30,000
• EMI = ₹1,30,000 ÷ 36 = about ₹3,611

With a reducing balance rate (also called diminishing balance), interest each month is charged only on what you still owe. Every EMI first pays that month's interest and the rest cuts the principal, so next month's interest is a little smaller. Home loans, bank car loans and almost all bank personal loans work this way.

The same ₹1 lakh at 10% reducing for 3 years has an EMI of ₹3,227 and total interest of ₹16,162. Same loan, same 36 months, same "10%" on paper. One costs ₹30,000 in interest, the other ₹16,162.

Why a flat 10% is really about 18%

The catch is in what you pay interest on. Halfway through a 3-year loan you have repaid a good chunk of the principal. A reducing-rate loan stops charging you on that part. A flat-rate loan keeps charging on the full ₹1 lakh till the last EMI.

So what is the real rate? Take the flat EMI of ₹3,611 and ask: at what reducing rate would ₹1 lakh over 36 months give this same EMI? The answer is 17.92%. Put 17.92% into the EMI calculator for ₹1 lakh and 3 years and it shows an EMI of ₹3,611 and interest of ₹30,004 (the ₹4 is rounding). That 17.92% is the true cost of a "flat 10%" loan, and the number to compare with other offers.

A rough rule: the real reducing rate is close to double the flat rate, usually somewhere between 1.7 and 1.85 times for the rates and tenures you will see in practice.

It works the other way round too. 10% reducing for 3 years costs ₹16,162, which is just 5.39% flat (₹16,162 ÷ ₹1 lakh ÷ 3). So "5.4% flat" for 3 years is the same deal as 10% reducing.

₹1 lakh for 3 years: the full comparison

The same ₹1 lakh, 3-year loan under a flat 10% and a few reducing rates (reducing rows from the EMI calculator):

A personal loan at 14% reducing, which sounds expensive, still costs about ₹7,000 less than the "flat 10%" offer. A 12% reducing loan saves about ₹10,400.

The EMI gap looks small, ₹190 to ₹380 a month. That is exactly why flat rates work so well in a showroom. Nobody walks out over ₹300 a month. The same trick works with tenure: a loan stretched longer can show a ₹200 lower EMI and still cost more in total interest, so look at the total repaid, not just the monthly figure.

Flat to reducing: the conversion table

Each cell is the reducing rate that gives the same EMI as the flat rate on the left, for that tenure. It does not depend on the loan amount.

The real rate dips a little for longer tenures but stays far above the flat number.

Also, a lender saying "2% a month" on the original amount is quoting a flat 24% a year. For a 1-year loan that works out to about 41.7% reducing. Local financiers and some informal lenders talk in exactly these terms.

For a rate or tenure that isn't in the table, the last section shows how to work it out yourself.

Where you still see flat rates

Banks quote reducing rates. Flat rates still turn up in a few places:

• Two-wheeler and used-car loans arranged at the dealer, especially through smaller finance companies.
• Consumer durable loans for phones, ACs, fridges and laptops.
• Some NBFCs and local finance companies, and almost all informal lending.

Often the word "flat" isn't even said. You hear "interest is only ₹9,000 a year", and the EMI is worked out on the full amount.

A car example. You are buying a used car and need ₹5 lakh for 5 years. The dealer's finance partner offers a flat 7.5%. Your bank offers 12.5% reducing.

The offer that sounds 5 points cheaper actually costs about ₹12,500 more. Check bank offers on the car loan EMI calculator before you meet the dealer's finance person. Tenure matters a lot on car loans too, and we compare that in car loan for 3, 5 or 7 years.

The Key Facts Statement: APR in black and white

This is where things have got better for borrowers. Under RBI's Key Facts Statement circular of 15 April 2024, every new retail and MSME term loan sanctioned from 1 October 2024 must come with a Key Facts Statement (KFS). This covers banks (small finance banks included), co-operative banks and all NBFCs, housing finance companies included. Credit card dues are not covered.

What the KFS has to give you:

• The APR (Annual Percentage Rate): the yearly cost of the loan including interest and all other charges, like processing fee.
• A full repayment schedule for the whole tenure.
• Third-party charges the lender collects from you, like insurance or legal fees, counted inside the APR and listed separately.
• A standard format, in a language you understand, valid for at least 3 working days (for loans of 7 days or more) so you can compare.

The strongest line in the circular: a charge not in the KFS cannot be levied at any stage of the loan unless you explicitly agree to it.

For loans taken through apps, the Digital Lending Directions, 2025 add two things. An app showing offers from several lenders must show each one's APR. And you get a cooling-off period of at least one day to exit by repaying the principal and proportionate APR, with no penalty.

So whatever the salesman says, a regulated lender's KFS has to show the APR, and a flat 10% for 3 years shows up there as roughly 18% or more once fees are added. Ask for the KFS before you sign, not after the bike is delivered. It stays valid for at least 3 working days, so there is no need to sign at the counter. Take it home and read it. If a lender won't give one, or the charges later don't match it, complain to the lender in writing first. If there's no reply in 30 days, you can go to the RBI Ombudsman through cms.rbi.org.in. Informal moneylenders don't follow any of this, which is one more reason to avoid them.

Processing fees, insurance and "no-cost EMI"

Even a proper reducing-rate loan costs more than its headline rate once fees come in. Say you take ₹1 lakh for 3 years at 11% reducing. EMI is ₹3,274 and total interest ₹17,859. Now add a 2% processing fee plus 18% GST, so ₹2,360, cut from the loan amount. You receive ₹97,640 but repay EMIs on the full ₹1 lakh.

The APR works out to about 12.66%, 1.66% above the brochure's "11%", from one fee. On a short loan a fee hurts more: the same loan over 1 year has an APR of about 15.5%.

Watch for these:

• Bundled insurance. Some lenders add a loan protection policy and fund the premium from your loan. If the lender collects it, it belongs in the APR. You can usually ask for it to be removed.
• "No-cost EMI". The interest is offset by a discount from the brand or seller, but you may still pay a processing fee, and on credit card EMIs GST is usually charged on the interest part. Check the final charge slip or card statement, not the banner.
• Documentation, stamp duty and "file charges". All of these should appear in the KFS.

Tax doesn't help either. Interest on a personal or consumer loan used for personal spending gets no deduction, so you bear the full APR. If the money goes into a house or a business, rules differ; ask a CA.

Closing a flat-rate loan early

The foreclosure amount on a flat-rate loan surprises people. Back to ₹1 lakh at a flat 10% for 3 years. After 18 EMIs you have paid ₹65,000, half of ₹1,30,000. It feels like you should owe ₹50,000.

You usually owe more. Lenders usually split each EMI using the real rate (17.92% here), so early EMIs carry more interest. On the EMI calculator's year-wise table at 17.92%, about ₹15,700 of the roughly ₹43,300 you pay in year one goes to interest, and the balance after one year is still ₹72,390. After 18 EMIs the principal left is about ₹56,600. Some lenders use an older method called the Rule of 78, which leaves about ₹57,300. Either way, not ₹50,000.

Then there's the foreclosure charge. RBI's Pre-payment Charges on Loans Directions, 2025 ban prepayment charges on floating-rate loans taken by individuals for non-business purposes, for loans sanctioned or renewed from 1 January 2026. Flat-rate loans are almost always fixed-rate, so that ban doesn't cover them. A lender can charge as per its policy, but only if the charge is disclosed in the sanction letter, the loan agreement and the KFS. Anything not disclosed can't be charged.

Before you prepay, ask for a written foreclosure statement. On whether to prepay at all, see prepaying a loan: reduce EMI or tenure.

When a flat rate is actually fine

Flat rates aren't a scam by themselves. They are easy to follow, and you know the total interest from day one. On a very short loan, say 3 to 6 months on a phone, the rupee gap stays small even when the rate gap looks big. And if the lender is honest about the APR, the label doesn't matter at all: a flat 5.4% for 3 years is the same deal as 10% reducing.

The trouble is that the headline number hides almost half the real cost, which is the main reason it is still used. You can't put "flat 9%" next to "12% reducing" without converting first, and prepaying saves less than you expect, often with a foreclosure charge on top.

So compare every loan on APR, or on the total repaid for the same amount and tenure, never on the headline rate. If the flat-rate offer still has the lower APR after fees, take it. Usually it won't.

For small purchases, the cheapest loan is often no loan. A ₹60,000 phone on a 12-month loan costs you interest. Saving ₹5,000 a month in a 12-month RD at 6.5% gives ₹62,143 on the RD calculator, so you earn ₹2,143 instead. For a gadget, waiting a year is usually possible.

Banks don't use flat rates on home loans. Your home loan EMI is already on reducing balance, same as the home loan EMI calculator. To see how that EMI is built month by month, read how EMI is calculated.

Checking any offer in two minutes

Back to the bike showroom. Say the offer is ₹1 lakh for 2 years at "9%", with a ₹1,180 file charge (₹1,000 plus GST) cut from the loan. Your bank has offered a personal loan at 12% reducing, with a 2% processing fee plus GST, so ₹2,360 cut from that one. Here is how to put the two side by side.

1. Ask two things at the counter. "Is this flat or reducing?", in those words, and "Can I see the KFS?" A regulated lender has to print the APR there, and that is the only number you need. For this offer it should read about 17.65%. If the answer is "you'll get it after the paperwork", that tells you something too.
2. No KFS yet? Work out the flat EMI. ₹1,00,000 × 9% × 2 = ₹18,000 interest, so ₹1,18,000 over 24 months, an EMI of ₹4,917.
3. Turn that EMI into a real rate. In Excel or Google Sheets, type =RATE(24,-4916.67,100000)*12 (months, EMI with a minus sign, loan amount). It returns 16.43%. No laptop? Open the personal loan EMI calculator on your phone, enter ₹1 lakh and 2 years, and move the rate up until the EMI reads ₹4,917.
4. Add the fee by shrinking the loan. Use the amount that actually reaches your account: =RATE(24,-4916.67,98820)*12 gives 17.65%. That is the APR. Do the same for the bank, an EMI of ₹4,707 on ₹97,640 received, and you get about 14.4%.
5. Check the total, then the exit. The showroom loan costs ₹1,19,180 all in (EMIs plus fee), the bank loan ₹1,15,336. Then ask what the foreclosure charge is, because fixed-rate loans can carry one.

So the "9%" offer is really 17.65%, and the "12%" bank loan, even with its bigger fee, is about 14.4%. The bank comes out roughly ₹3,800 cheaper on a ₹1 lakh loan. Nothing fancy went into that: one question, one formula, and the amount you actually receive.

The habit worth keeping is simple. Treat any rate quoted without the word "reducing" as flat until someone shows you otherwise, and don't sign on the day you hear the number. The KFS gives you three working days. Use at least one of them.

Written by the Gainly team for general information, not as investment or tax advice. Rates and rules change, so check the latest before you decide; tell us if something here is out of date. Contact