Flat Rate to Effective Interest Rate Calculator
A quoted "flat rate" almost always understates what borrowing really costs. Enter a flat-rate loan and see the estimated effective (reducing-balance-equivalent) annual rate, so you can compare like with like.
Estimated result
I help Malaysian SMEs get their numbers — and their systems — right with Bukku accounting software. These calculators are a free resource I share — not financial, credit or property advice.
Message Faiz on WhatsApp →Why flat rate and effective rate differ
Under a flat rate, interest is charged on the full original amount for the entire tenure, regardless of how much you have already repaid. Under a reducing-balance method, interest is charged only on the outstanding balance, which falls each month. Because a flat rate keeps charging on money you have already paid back, its true (effective) cost is roughly 1.8–1.9× the headline flat number for a typical multi-year loan.
How this estimate is calculated
First we compute total interest as loan × flat rate × years, add it to the loan for total repayment, and divide by the number of months for the instalment. We then find the monthly reducing-balance rate that would produce that same instalment on your loan over the same tenure, and annualise it. That annualised figure is the estimated effective annual interest rate based on the repayment assumptions entered.
This is an educational estimate, not a regulated disclosure. An actual product's disclosed effective rate or APR may use a lender-specific methodology (day-count, fees, insurance, timing of payments) that differs from this simplified model.
Where you'll see flat rates in Malaysia
Flat rates have traditionally appeared on some personal financing and older vehicle hire-purchaseproducts. Note that from 1 June 2026, the Hire-Purchase (Amendment) Act 2026 moved new hire-purchase agreements to reducing-balance pricing with an effective interest rate (EIR); flat-rate structures are being phased out for new agreements. Not every product uses the same pricing, so always check your specific offer.
Frequently asked questions
Is the "effective rate" here the same as APR?
Not necessarily. We estimate the reducing-balance-equivalent annual rate from your repayment stream. A lender's regulated APR may include fees and use a specific methodology, so treat this as a comparison estimate.
Why is my effective rate almost double the flat rate?
That is normal. A flat rate charges interest on the full original sum throughout, so the effective cost on the reducing balance is much higher.
Are my figures stored?
No. The calculation runs entirely in your browser and nothing is saved or sent.
Sources & methodology
- Flat vs reducing-balance conversion — standard financial mathematics.
- Association of Banks in Malaysia — hire-purchase move to EIR / reducing balance (effective 1 June 2026).
Disclaimer: Estimates for general information and planning only — not financial advice or a regulated rate disclosure. Actual rates, fees and methodology depend on the relevant financial institution and product terms.