Flat interest rates and reducing balance interest rates are the two important approaches for calculating interest on a personal loan. Selecting between flat and reducing interest rates can significantly influence the overall interest cost, so it’s important to understand these options before signing an agreement for a personal loan.
Interest is calculated on the original full loan amount, every single month, throughout the entire loan tenure.
Even after you have repaid half the loan, the interest continues to be charged on the original amount. You essentially pay for money you no longer owe.
Interest is calculated only on the outstanding loan balance, which reduces with every EMI payment you make.
As your principal reduces each month, the interest component of your EMI also reduces. You pay interest only on what you actually still owe.
| Feature | Flat Interest Rate | Reducing Balance Interest Rate |
|---|---|---|
|
Interest calculated on |
Full original loan amount |
Remaining outstanding balance |
|
Monthly interest amount |
Stays the same throughout |
Decreases every month |
|
Total interest paid |
Higher |
Lower |
|
Transparency |
Less transparent |
More transparent |
|
Effective cost |
Much higher than the stated rate |
Close to stated rate |
|
Common users |
Some NBFCs, short-term lenders |
Most banks (SBI, HDFC, ICICI, etc.) |
|
Suitable for |
Very short-term, small loans only |
Medium to long-term loans |
Flat rate charges interest on what you borrowed. Reducing balance rate charges interest on what you still owe. There is a big difference. This can be understood by following example, in which there is same loan amount, same interest rate, same tenure with a different method of calculating the interest rate.
Loan Details:
| Parameter | Flat Rate @ 12% | Reducing Rate @ 12% |
|---|---|---|
|
Monthly EMI |
~₹11,333 |
~₹9,964 |
|
Total Amount Paid |
₹4,08,000 |
₹3,58,704 |
|
Total Interest Paid |
₹1,08,000 |
₹58,704 |
|
Extra Cost vs Reducing |
₹49,296 more expensive |
— |
Important: A 12% flat rate loan costs you ₹49,296 more than a 12% reducing balance loan on just ₹3 lakh over 3 years. On a larger loan or longer tenure, this gap becomes even wider.
Understanding interest calculation is just as important as comparing Personal Loan Interest Rates.
The reducing balance rate is the better choice in most of the cases, especially for personal loan more than ₹1 Lakh. It is cheaper, more transparent, and the rate you see is genuinely close to the rate you pay. A flat rate loan might be acceptable for a very small, very short-term loan (say ₹20,000 for 3 months) where the absolute rupee difference is minimal, and convenience outweighs cost.
Yes. A 12% flat rate on a ₹3 lakh loan for 3 years works out to an effective cost of approximately 21–22% on a reducing basis. Meanwhile, a genuine 18% reducing rate on the same loan would cost considerably less in total interest. Always compare total repayment amounts, not just the stated rates.
The majority of scheduled commercial banks, including SBI, HDFC Bank, ICICI Bank, Axis Bank, and Kotak Mahindra Bank etc., use the reducing balance method for personal loans. Some smaller NBFCs and informal lenders still use flat rate calculations. Always confirm the method with your specific lender before accepting any loan offer.
Yes. Even if two lenders quote a similar EMI, a flat-rate loan will have a much higher total repayment amount because you are paying more interest over the full tenure. The EMI alone does not tell the complete story. Always look at the total amount payable and the amortisation schedule to compare loans accurately.
Yes. Reducing balance rate, diminishing balance rate, and declining balance rate all refer to the same method. Here, interest is calculated on the outstanding principal balance, which reduces with every EMI payment. Different lenders and documents may use different terms, but the calculation logic is identical.
As a random thumb rule, a flat interest rate is approximately 1.7 to 1.9 times higher than the equivalent reducing balance rate. For example, a 12% flat rate is roughly equivalent to a 21–22% reducing balance rate.
