Flat Rate vs Reducing Balance: The Hidden Cost Most Borrowers Miss
A salesperson quotes you "12% flat rate." Your friend got a loan at "21% reducing balance." Who got the better deal? Most people say the 12% loan — but they're wrong. Understanding this difference can save you tens of thousands of rupees on your next loan.
What Is a Flat Rate?
Under the flat rate method, interest is calculated on the original principal for the entire loan tenure, regardless of how much you've repaid. So on a ₹5 lakh loan at 12% flat for 3 years, the total interest = ₹5,00,000 × 12% × 3 = ₹1,80,000, and your monthly EMI = (5,00,000 + 1,80,000) ÷ 36 = ₹18,889.
What Is Reducing Balance?
Under the reducing balance method (used by all scheduled banks for standard loans), interest is charged only on the outstanding principal after every EMI payment. As you repay, the interest component shrinks each month.
A Direct Comparison: ₹5 Lakh, 3 Years
| Method | Quoted Rate | EMI | Total Interest | Effective Annual Rate |
|---|---|---|---|---|
| Flat Rate | 12% | ₹18,889 | ₹1,80,000 | ~21.5% |
| Reducing Balance | 21% | ₹18,763 | ₹1,75,480 | 21% |
The "12% flat" loan effectively costs you 21.5% per annum on a reducing balance basis — and is actually more expensive than the "21% reducing" loan.
Rule of thumb: To convert a flat rate to an approximate reducing balance rate, multiply the flat rate by 1.75–1.85. So 12% flat ≈ 21–22% reducing balance.
The Conversion Formula
where n = number of instalments
For 36 instalments: 12% × (72/37) ≈ 12% × 1.946 = 23.35% (a more precise estimate than the rule of thumb above).
Where Are Flat Rates Still Used?
Flat rates are commonly quoted by:
- Microfinance institutions and cooperative banks
- Vehicle dealers offering in-house financing
- Informal lenders and chit funds
- Some small NBFC personal loan products
Scheduled commercial banks are not permitted to charge flat interest on standard retail loans under RBI guidelines. If a bank representative quotes you a flat rate, ask them to state the Annual Percentage Rate (APR) — they are legally required to provide it.
Always Ask for the APR
The Annual Percentage Rate (APR) is the single number that lets you compare any two loan products on equal terms, regardless of whether they use flat or reducing balance methods. Under the RBI's Key Fact Statement mandate, all lenders must disclose the APR before you sign.
Compare Loan Costs Accurately
Our EMI calculator uses the reducing balance method — the same as all Indian banks — so you always see the true cost.
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