What Is Reducing Interest Rate?

Updated on Wednesday, September 16th, 2026 | By IndusInd Bank

Interest rates are a key factor in determining the cost of borrowing. But not all interest rates are calculated the same way. While some loans come with a flat interest rate, others use a method called the reducing interest rate—often considered more borrower-friendly in the long run. In this blog, we’ll break down how reducing interest rates work, their advantages, and why they might be a better option for your personal loan.

Understanding Reducing Interest Rate

A reducing interest rate, meaning a diminishing or declining balance interest rate, is a method of calculating interest where the interest is charged on the outstanding loan balance. As you repay the principal amount, the interest is recalculated on the reduced principal amount, leading to a gradual decrease in the total interest paid over the loan tenure.

This type of rate offers better value for borrowers, especially for longer tenures, since the interest payable declines with each EMI.

Here’s a simplified illustration:

• Imagine you take a loan of ₹ 1,00,000 with a reducing interest rate of 10% per annum.
• In the first month, the interest is calculated on the entire loan amount (₹ 1,00,000).
• After your first repayment, the principal reduces.
• In the second month, the interest is calculated on the new, reduced principal amount, and this process continues throughout the loan tenure.

This method is in stark contrast with a flat interest rate, where the interest is calculated on the original principal amount for the entire duration of the loan, resulting in higher interest payments.

How does reducing interest rate work?

The process works in the following way:

1. The lender decides the loan amount, annual interest rate and repayment period.
2. The annual interest rate is converted into a monthly rate.
3. Interest for the first month is calculated on the outstanding principal.
4. Your EMI pays the interest and a part of the principal.
5. The principal reduces after every EMI.
6. Interest for the next month is calculated on the new balance.

For example, if you borrow ₹1,00,000 and repay part of the principal through your first EMI, the next month’s interest will be calculated on the balance that remains. The interest amount gradually falls as you continue making repayments.

The EMI amount depends on the loan amount, interest rate and tenure. A longer tenure generally reduces the monthly EMI but increases the total interest paid over the loan period.

Reducing Interest Rate Formula

Here’s the formula used to calculate the EMI under a reducing interest rate:

EMI = [P × R × (1+R)^N] / [(1+R)^N – 1]

Where:

• P = Principal loan amount
• R = Monthly interest rate (annual rate divided by 12 × 100)
• N = Loan tenure in months

This formula factors in both the principal and the declining interest, offering a realistic picture of monthly outgo.

Benefits of a Reducing Interest Rate

A reducing interest rate offers several advantages, especially for those looking to minimize total interest paid over the loan duration:

Lower Interest Payments

Since the interest is calculated on the diminishing principal, the total interest paid over the loan tenure is significantly lower compared to a flat interest rate loan.

Transparency

Borrowers can easily see how their repayments are reducing the principal and the interest component using a loan repayment schedule. Thus, offering clarity and peace of mind.

Cost-Effective

Particularly for long-term loans, reducing interest rates prove to be more economical than flat interest rates.

Also Read: Understanding Personal Loan Interest Rates

Wrapping Up: Why Reducing Interest Rate Is the Smarter Choice

A reducing interest rate is often more cost-effective because interest is charged on the loan balance that remains after each repayment. The benefit is usually more noticeable when the loan amount or repayment period is larger.

Do not compare loans only by looking at the advertised interest rate. Ask for the total interest, total repayment amount and complete EMI schedule. Also check the processing fee and other charges before signing the agreement.

For a broader explanation, read Flat vs reducing interest rate.

Frequently Asked Questions

Q1. Do all personal loans use reducing interest rate?

No. Some lenders or loan products use a flat interest method, while others use a reducing-balance method. Check your loan agreement and repayment schedule to know how the interest will be calculated.

Q2. Is reducing interest rates good or bad?

A reducing interest rate is generally more favourable than a flat rate when the loan amount, quoted rate and tenure are the same. However, compare the total repayment amount and all charges before choosing a loan.

Q3. How to convert reducing interest to flat rate?

There is no single conversion that works for every loan. The comparison depends on the loan amount, interest rate, tenure and repayment schedule. Ask the lender for the total interest and total repayment under both methods instead of simply multiplying or dividing the rate.