Car Finance

Comparison Rate vs Interest Rate: What's the Difference?

By Joseph Nowland, Director and Senior Finance Broker · 18 July 2026 · 3 min read

Last reviewed 26 July 2026

Two numbers, one loan

Australian credit advertising shows two rates side by side. The interest rate, and a comparison rate that is almost always higher. The interest rate is the percentage used to calculate the interest charged on your balance. The comparison rate is a legally required figure that folds the loan's unavoidable upfront and ongoing charges into a single annualised percentage.

The comparison rate exists because a loan's headline rate can be made to look attractive while the true cost hides elsewhere. By law, credit providers advertising a rate must show the comparison rate alongside it, calculated on a standardised basis so borrowers can compare offers on more than the headline.

What the comparison rate includes, and what it misses

The comparison rate bundles the interest rate with the known, compulsory costs of the loan into one figure. That makes it a far better first filter than the headline rate alone. A loan whose comparison rate sits well above its interest rate is telling you the paperwork carries weight the headline does not show.

It's not a complete answer, though, since the standardised calculation is based on a fixed example, typically $30,000 over five years for personal loans, and your loan will differ in size, term and structure. Costs that depend on how you use the loan, along with optional extras, sit outside it. Two loans can share a comparison rate and still cost you different amounts in practice.

Kitchen bench with a laptop, car keys and a fresh coffee

Where the gap between the two rates comes from

A small gap between interest rate and comparison rate means the loan's fixed costs are light. A large gap means the opposite. When you see a striking headline rate with a comparison rate far above it, the offer is leaning on the headline while recovering cost elsewhere, and the comparison rate is doing exactly the job it was designed for by exposing that.

This is especially worth watching in promotional dealer finance, where a very low advertised rate on a specific model can coexist with a much less exciting comparison rate, and with a vehicle price that quietly absorbs the difference. Compare the whole deal, including the price you are paying for the car and the total cost of the money.

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The number that settles arguments is total amount repayable

For a decision between two specific loan offers, the cleanest figure is the total amount repayable, meaning every repayment plus the balloon, summed over the life of the loan. It reflects your actual amount, term and structure rather than a standardised example, and it makes structural differences visible.

This matters particularly with balloon payments, because a balloon lowers the repayment while raising the total cost. It also matters with long terms, where a lower rate over more years can still cost more than a higher rate over fewer. Rate compares the price of the money. Total repayable compares the actual deal.

Timber desk by a rain-flecked window with car keys, a loan document and a coffee, hatchback parked outside

Using both numbers like a broker does

In practice, use the comparison rate to screen advertised offers, then use the total amount repayable, worked out on your real amount and term, to choose between shortlisted structures. Check both on like terms, and be suspicious of any offer that resists showing the total.

When Morella Finance compares car loans across the panel, offers are presented with rates, terms and total costs side by side before you commit. The two advertised rates are the start of the comparison, not the end of it.