Flat vs Reducing Rate Calculator
See the true effective rate behind any flat quote — and exactly how much extra it carries.
Convert a flat quote
the headline number the lender quotes.
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15.7%
Your 9.0% flat quote on ₹10.00 L over 5 years really charges 1.75× the headline rate
Effective rate = the reducing-balance rate whose EMI matches this flat quote's EMI. Real products may add fees or insurance not modelled here — a planning estimate, not a final quote.
A flat number always hides a much higher real rate. Here's the gap.
A 9.0% flat rate is really about 15.7% on a reducing-balance basis — about 1.75× the headline. Over 5 years, that flat quote costs you ₹2,04,499 more in interest than the same headline rate charged on the outstanding balance — roughly 20% of everything you borrowed, handed over for nothing.
Total interest, flat vs reducing
Same 9.0% headline, same 5 years — charged two ways.
Reducing rate
9.0% honest
Flat rate
9.0% flat
+₹2.04 L
extra interest the flat method extracts (45% more)
What the flat quote costs you
Principal
₹10.00L
what you borrow
Flat interest
₹4.50L
45% of the loan
Total payable
₹14.50L
over 5 years
The flat quote also raises every single instalment — each flat EMI is ₹3,408 more than the honest reducing EMI at the same headline rate.
The effective-rate reveal
Where this 9.0% flat quote really sits on a reducing-balance scale.
Headline flat
9.0%
what's advertised
True reducing rate
15.7%
what you actually pay
Rate multiple
1.75×
effective ÷ headline
Extra on each EMI
+₹3.4K
flat EMI − reducing EMI
The effective rate is found by solving for the reducing-balance rate whose EMI equals this flat quote's EMI — the same standard amortization used by mainstream bank loans. There is no fixed multiplier; longer tenures push the multiple higher because the flat method keeps charging on principal you repaid years ago.
Interest paid over the term, both ways
The amber line (flat) climbs in a straight line; the honest reducing line bends away below it. The gap is the flat penalty, growing every month.
- Flat interest paid
- Reducing interest paid (honest)
Flat total interest
₹4.50 L
Reducing total interest
₹2.46 L
Overpaid by choosing flat
₹2.04 L
Outstanding balance — both ways
How much principal you still owe over the term (charted in the result panel above). The honest reducing loan falls faster; the flat loan repays evenly, so you carry more debt for longer.
Year 1
₹8.34L
Year 3
₹4.54L
Year 4
₹2.37L
Year 5
₹0
Reducing balance left at each milestone year.
Year-by-year balance (honest reducing schedule)
Outstanding balance, cumulative principal repaid and cumulative interest paid at the end of each of the 5 years, on the honest reducing-balance schedule at the same 9.0% headline.
| Year | Outstanding balance | Principal paid | Interest paid |
|---|---|---|---|
| Start | ₹10.00 L | ₹0 | ₹0 |
| Year 1 | ₹8.34 L | ₹1.66 L | ₹83,270 |
| Year 2 | ₹6.53 L | ₹3.47 L | ₹1.51 L |
| Year 3 | ₹4.54 L | ₹5.46 L | ₹2.02 L |
| Year 4 | ₹2.37 L | ₹7.63 L | ₹2.34 L |
| Year 5 | ₹0 | ₹10.00 L | ₹2.46 L |
Change the flat rate or tenure on the same ₹10.00 L and watch the effective rate move.
Flat rate
Effective rate
15.7%
1.75× headline
Flat EMI
₹24.2K
per month
Flat interest
₹4.50L
over 5 years
Extra vs reducing
₹2.04L
overpaid interest
Flat-rate conversion table
On ₹10.00 L over 5 years — what each flat rate really costs.
| Flat rate | Effective rate | Multiple | Flat EMI | Flat interest | Extra vs reducing |
|---|---|---|---|---|---|
| 5.0% | 9.2% | 1.83× | ₹20,833 | ₹2.50 L | ₹1.18 L |
| 6.0% | 10.8% | 1.81× | ₹21,667 | ₹3.00 L | ₹1.40 L |
| 7.0% | 12.5% | 1.79× | ₹22,500 | ₹3.50 L | ₹1.62 L |
| 8.0% | 14.1% | 1.77× | ₹23,333 | ₹4.00 L | ₹1.83 L |
| 9.0%your quote | 15.7% | 1.75× | ₹24,167 | ₹4.50 L | ₹2.04 L |
| 10.0% | 17.3% | 1.73× | ₹25,000 | ₹5.00 L | ₹2.25 L |
| 11.0% | 18.8% | 1.71× | ₹25,833 | ₹5.50 L | ₹2.45 L |
| 12.0% | 20.3% | 1.69× | ₹26,667 | ₹6.00 L | ₹2.65 L |
| 14.0% | 23.2% | 1.66× | ₹28,333 | ₹7.00 L | ₹3.04 L |
Notice the multiple is fairly stable across rates at a fixed tenure — it's the tenure, not the rate, that drives how dear a flat quote becomes.
- The real rate here is 15.7%, not 9.0%.
- The gap equals ~8 extra EMIs — ₹2.04 L for nothing.
- Banks quote reducing; flat lurks in dealer & durable EMIs.
What this means
On a ₹10.00 L loan, a 9.0% flat quote charges ₹4.50 L in interest — against just ₹2.46 L if the same rate were applied honestly on the reducing balance. That gap of ₹2.04 L is the price of the flat method — like handing over 8 extra EMIs (0.7 years of instalments) for nothing. The real cost of borrowing here is 15.7%, not 9.0% — always convert before you sign.
Key takeaways
- Headline flat rate: 9.0%
- True effective rate: 15.7% (1.75× headline)
- Flat EMI: ₹24,167/mo vs reducing ₹20,758/mo
- Total interest (flat): ₹4.50 L
- Extra vs a reducing loan: ₹2.04 L
- Total payable: ₹14.50 L vs ₹12.46 L reducing
What flat-rate lenders don't tell you
Interest is fixed on day one
Computed once on the full ₹10.00 L and split evenly across every month — it never falls, however fast you repay.
You pay on money you've returned
Even in the final year you're charged on the original principal, not the little that's left. That's the trick.
The EMI is higher every month
Each flat instalment is ₹3,408 more than the honest reducing EMI for the same headline rate.
Effective rate ≈ 1.75× the headline
Your 9.0% flat quote behaves like 15.7% on a reducing balance — convert before you sign.
Where you'll meet reducing rates
- Home loans and mortgages
- Bank car loans
- Personal loans from banks & NBFCs
- Education and gold loans (most)
The fair, mainstream way — interest only on what you still owe.
Where flat rates still lurk
- Consumer-durable & no-cost EMI offers
- Dealer car-finance schemes
- Some two-wheeler & short-term loans
- A few informal or chit-style lenders
Often used precisely because the flat number looks smaller next to a reducing quote.
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Your quote: 9.0% flat on ₹10.00 L over 5 years — really 15.7% reducing.
Plan the loan beyond the quote
Turn the converted rate into a decision — check the EMI, or find a cheaper way to borrow.
Every figure is computed from the standard amortization formula — nothing is hardcoded. Real flat-rate products may add processing fees or insurance not modelled here, and any rate shown is illustrative. Treat these figures as a clear planning estimate, not a final quote.
How a flat rate converts to a reducing rate
Flat interest = P × r × n → solve for i where reducing EMI(i) = flat EMI
- P
- loan principal
- r
- flat rate per year
- n
- tenure in years
- i
- the effective reducing rate this page solves for
Worked example
With your inputs — ₹10.00 L at 9.0% flat over 5 years: interest is fixed at ₹4.50 L on day one, giving a flat EMI of ₹24,167 — and the reducing-balance rate that produces the same EMI works out to about 15.7%. A flat rate charges interest as P·r·n — on the full original principal for the entire tenure — so you keep paying on money you have already repaid. The effective reducing rate shown is found by solving for the reducing-balance rate whose EMI equals the flat EMI, the same standard amortization formula used by the /calculators/emi tool.
Flat vs reducing rate questions
A flat interest rate is charged on the full original loan amount for the entire tenure, no matter how much you have already repaid. A reducing-balance (or diminishing) rate is charged only on the outstanding balance, which falls with every instalment. Because the flat method ignores your repayments, the same headline number costs far more under a flat quote than under a reducing one.
Under a flat rate the interest is computed once, on the whole principal, and spread across the term — so you keep paying interest on money you have already returned to the lender. On a reducing basis you only pay interest on what you still owe. That is why a flat rate of, say, 9% behaves like a reducing rate of roughly 16–17%: the true cost is nearly double the advertised figure.
There is no simple multiplier — the conversion depends on the tenure. The exact way is to find the reducing-balance rate whose EMI equals the flat-rate EMI, which this calculator does for you by solving the amortization formula. As a rough guide, for typical multi-year loans the effective reducing rate is around 1.7 to 1.9 times the flat rate, with longer tenures pushing the multiple higher.
Most mainstream bank loans — home loans, car loans and personal loans — are quoted and serviced on a reducing-balance basis. Flat rates still appear in some consumer-durable finance, dealer schemes and a few short-term products, often because the flat number looks smaller. Always ask whether a quoted rate is flat or reducing before comparing two offers.
No. For the same headline rate, a flat-rate EMI is higher than a reducing-balance EMI, because the flat method front-loads more total interest into the loan. This calculator shows the flat EMI and works out the reducing rate that would produce the very same EMI — that reducing rate, not the flat number, is the true cost of the loan.
Flat-rate quoting is not illegal in most markets, but it is widely seen as misleading because the headline looks far cheaper than the real cost. Many regulators require lenders to also disclose an annual percentage rate (APR) or effective rate. When you see a low flat number, convert it first — the effective reducing rate is what you should compare against other offers.
The complete guide to flat vs reducing rates
Why the way interest is charged matters
The way a lender calculates interest matters as much as the rate they quote. With a flat rate, interest is worked out once on the entire amount you borrowed and then divided evenly across the term. You go on paying interest on the original sum even after you have repaid most of it — which is why a flat quote is so much costlier than it first appears. A reducing-balance rate, by contrast, charges interest only on what you still owe, so the interest portion shrinks with every instalment.
How a flat rate is calculated
Flat interest is simply principal × flat rate × years. For a ₹10.00 L loan at 9.0% flat over 5 years, the total interest is fixed at ₹4.50 L on day one and never changes, however fast you repay. That total, plus the principal, is divided by the number of months to give a flat EMI of ₹24,167. Notice the interest doesn't depend on your repayment schedule at all — that's the heart of why it's expensive.
Converting a flat rate to a reducing rate
There is no fixed multiplier — the conversion depends on the tenure. The exact method is to find the reducing-balance rate whose EMI equals the flat-rate EMI, which this calculator solves for you. Here a 9.0% flat rate works out to about 15.7% on a reducing basis — roughly 1.75 times the headline. As a rough rule, multi-year flat loans land around 1.7 to 1.9 times the flat rate, and longer tenures push the multiple higher because the flat method keeps charging on principal you repaid years ago.
Where you'll meet flat rates
Most mainstream bank loans — home loans, car loans and personal loans — are quoted and serviced on a reducing-balance basis. Flat rates still surface in consumer-durable finance, dealer car schemes, some gold loans and short-term products, often precisely because the flat number looks smaller next to a reducing quote. A 7% flat headline can quietly be a 13% effective rate. Whenever you see a flat number, convert it first and compare like with like.
How to use this when comparing offers
Always ask whether a quoted rate is flat or reducing before you compare two loans. If one lender quotes a flat rate and another a reducing rate, convert the flat number to its effective reducing equivalent — only then are you comparing the real cost of borrowing. A flat quote that looks cheaper on paper is frequently the dearer loan once converted.
A note on "no-cost" and zero-percent EMIs
Many "no-cost EMI" offers are flat schemes in disguise — the interest is folded into the price or charged up front as a processing fee, then the balance is split flat across the term. Convert the implied rate the same way and you'll often find a real cost well above zero. Treat any rate here as illustrative and confirm the exact terms, fees and method with the lender before committing — these are projections to inform a decision, not a final quote.