Two lenders offer you the same loan: one advertises "8% flat", the other "14% reducing". Which is cheaper? Many borrowers pick the lower-looking number and later discover they are paying far more than they expected. The two quoting methods are not directly comparable, and knowing how each works can save you real money.
Key takeaways
- Flat rate: interest on the original amount for the whole term.
- Reducing balance: interest on the remaining balance.
- A flat rate is equivalent to a reducing-balance rate of roughly 1.7 to 2 times the stated figure.
- Always compare total repayment and effective rate.
How flat-rate interest works
Total interest = principal × flat rate × years, spread equally over the instalments.
Example: borrow 100,000 for 3 years at 10% flat.
- Interest = 100,000 × 10% × 3 = 30,000
- Total repayment = 130,000
- Monthly payment = 130,000 ÷ 36 = 3,611
Even though you owe less every month, interest is always charged as if you still owed the full 100,000.
How reducing-balance interest works
Each month, interest = outstanding balance × (annual rate ÷ 12). Your EMI is fixed, but the share going to interest falls and the share going to principal rises.
Example: borrow 100,000 for 3 years at 10% reducing balance.
- Monthly EMI ≈ 3,227
- Total repayment ≈ 116,170
- Total interest ≈ 16,170
Same stated number (10%), but the reducing loan costs about 13,800 less in this example. Try the numbers yourself in our EMI calculator.
Side-by-side comparison
| Item (100,000 for 3 years at 10%) | Flat | Reducing balance |
|---|---|---|
| Monthly payment | about 3,611 | about 3,227 |
| Total interest | 30,000 | about 16,170 |
| Total repayment | 130,000 | about 116,170 |
| Effective annual rate | about 17.8% | 10% |
The effective annual rate of the flat loan (the rate that would give the same instalments on a reducing loan) is about 17.8 percent, nearly double the headline.
Rough conversion between flat and reducing
For a quick estimate, the equivalent reducing rate is a little below double the flat rate for typical terms. The exact figure depends on the tenure, so calculate it instead of guessing.
| Flat rate | Approx. equivalent reducing rate (3-year loan) |
|---|---|
| 6% | about 11% |
| 8% | about 14.5% |
| 10% | about 17.8% |
| 12% | about 21% |
These are approximations for a 36-month loan with monthly payments; shorter or longer terms change the result.
How to compare loan offers properly
- Ask for the total amount you will repay over the full term.
- Ask for the effective annual rate (APR, EIR or IRR) including fees.
- List every fee: processing, insurance, documentation, late payment, early repayment.
- Ask for the amortisation schedule showing principal and interest each month.
- Check prepayment terms: penalties, minimum amounts and whether the interest saved is real.
- Compare two offers on the same term and amount.
Where each method is common
- Reducing balance: most home loans, many personal and car loans from banks, and credit lines.
- Flat rate: some consumer-finance loans, hire purchase, microfinance products and shop financing in some markets.
Regulations differ by country, and some regulators require lenders to show an effective rate. Check the rules where you live.
Does early repayment help?
With a reducing-balance loan, paying early cuts the outstanding balance, so future interest falls immediately. With flat-rate loans, the interest may already be fixed, and lenders often apply a formula (such as the "rule of 78") that returns only part of it. Always ask: "If I repay after 12 months, exactly how much will I owe?"
Ways to lower your loan cost
- Shop around and negotiate the rate and fees.
- Choose the shortest term you can afford.
- Make extra payments when allowed: try the prepayment option in the EMI calculator.
- Avoid add-ons you do not need, such as costly insurance bundles.
- Improve your credit profile before applying where credit scores exist.
- Build savings so you borrow less; see the 50/30/20 budget guide and how compound interest works.
Business loans and invoices
Small businesses often borrow for equipment or stock. Compare options with your cash-flow forecast and keep proper records; see how to write a business plan and how to create an invoice.
Disclaimer
This article is general education. Loan terms, regulations and calculations vary by lender and country. Read your contract carefully and consider independent financial advice before borrowing. Need software for loans, billing or finance workflows? Talk to our team.
