If you’ve ever looked at a home loan advertisement, you’ve seen two numbers sitting next to each other. One is large and bold, the interest rate. The other is smaller, often in fine print, labelled the comparison rate. Most people register the first number and skip straight past the second.

That’s a mistake, and it’s one the law itself was designed to prevent. Here’s what a comparison rate actually is, why every lender in Australia has to show you one, and what it does and doesn’t tell you.

The basic definition

ASIC’s MoneySmart service, the government’s consumer finance guidance arm, describes a comparison rate as a rate that helps you work out the true cost of a loan. It combines the interest rate with most of the fees and charges attached to that loan, and reduces the lot to a single percentage figure (ASIC MoneySmart).

In practice, that means two loans can carry the exact same headline interest rate and still cost you differently once you factor in application fees, ongoing account-keeping fees, and other charges. The comparison rate is meant to surface that difference in one glance, rather than leaving you to add it all up yourself from a fee schedule buried in the product disclosure document.

Why this isn’t a lender’s choice to make

It would be easy to assume the comparison rate is just good practice that lenders have adopted voluntarily. It isn’t. Displaying a comparison rate alongside an advertised interest rate is a legal requirement under Part 10 of the National Credit Code, which sits as Schedule 1 to the National Consumer Credit Protection Act 2009 (ASIC, National Credit Code overview). The requirement applies whenever a credit provider advertises a fixed-term loan used mainly for personal, domestic or household purposes, which covers the overwhelming majority of home loans advertised to everyday borrowers.

The rule exists because of a genuine problem the regulator was trying to solve. Before a national comparison rate regime came into effect in 2010, a lender could advertise an eye-catching low interest rate while charging fees that only became apparent once you were already partway through the application, or worse, after settlement. ASIC’s own description of the regime states its purpose plainly: to inform consumers of the true cost of credit and make it easier to compare products across the market (ASIC, National Credit Code overview).

So when you see a comparison rate next to an interest rate, you’re not looking at a marketing flourish. You’re looking at a federally mandated disclosure that exists specifically to stop a particular kind of misleading advertising that used to be common practice.

The standard example behind every comparison rate

Here’s a detail that trips a lot of borrowers up, and it’s worth understanding before you take any advertised comparison rate at face value.

Every comparison rate you see is calculated using the same standardised example, set out in Regulation 71 of the National Consumer Credit Protection Regulations 2010: a loan of $150,000 over a term of 25 years (Regulation 71, National Consumer Credit Protection Regulations 2010). That standard basis is what makes it possible to compare one lender’s advertised rate fairly against another’s, since every lender is required to run the same calculation on the same hypothetical loan.

The catch is that your own loan almost certainly doesn’t look like that example. Plenty of borrowers are taking out loans well above $150,000, and 30-year terms are now more common than 25-year ones for owner-occupier lending. When a loan is bigger and the term is longer, a fixed-dollar fee like an annual package fee makes up a smaller proportion of the total cost than it would on the standardised $150,000/25-year example. That means the comparison rate you see advertised can overstate the real-world impact of fixed fees on your actual loan amount.

None of this makes the comparison rate useless. It still gives you a fast, standardised way to shortlist lenders before you go further. It just means the advertised figure is a starting point for comparison between lenders, not a precise prediction of what your own loan will cost.

What a comparison rate leaves out entirely

Alongside the standardised example problem, there are real costs that sit outside the comparison rate calculation altogether. ASIC’s own guidance on the National Credit Code notes that a comparison rate does not include every fee and charge associated with a loan (ASIC, National Credit Code overview). In practice, that generally means:

• Government charges, such as stamp duty and mortgage registration fees, which vary by state and by purchase price and sit entirely outside the calculation.
• Discharge or exit fees, which only become relevant if and when you refinance away from that lender, so they’re absent from the number you compared on day one.
• Lenders Mortgage Insurance, which can run into five figures if you’re borrowing above 80% of the property value, and isn’t reflected in the comparison rate at all.

The comparison rate also can’t capture things that make a loan more or less suitable for you personally, rather than more or less expensive in isolation. ASIC notes that the comparison rate only allows comparison based on cost, and won’t reflect features like fee-free offset accounts or flexible repayment options that might make one loan genuinely more valuable to you than a cheaper-looking alternative.

What this means when you’re actually comparing loans

Treat the comparison rate as your first filter, not your final answer. It’s a genuinely useful, legally standardised way to quickly rule out loans that are carrying heavy fees behind an attractive headline rate. From there, the real comparison has to go further than the number on the page.

Two loans with similar comparison rates can still differ substantially once you account for your actual loan size, your actual term, whether you’ll use an offset account, and whether you’re likely to want to refinance again in a few years. A comparison rate calculated on a $150,000 loan over 25 years tells you very little about how a $700,000 loan over 30 years will actually behave, even though it’s the number both lenders are legally required to advertise.

This is really where the distinction between comparing rates yourself and having someone run your actual numbers becomes meaningful. A comparison site can show you rates. Working out your genuine comparison rate, on your loan size, your term, and your circumstances, alongside checking whether you’d actually be approved for it, is a different exercise entirely.

If you’d like your real comparison rate worked out properly, on your numbers rather than the standardised example, get in touch with the hfinance team. We compare across 50+ lenders and can show you what a loan actually costs for your situation, not just what the ad says.

This article is general information only and does not take into account your personal financial situation or objectives. Speak with an hfinance broker before making any lending decisions.