The litre, taken apart
Every weekday the Australian Institute of Petroleum publishes the terminal gate price, which is what the big wholesalers charge a retailer to collect fuel from a terminal in each capital city. It is the closest thing Australia has to a published cost price for fuel, and it already includes both taxes. Here is the national average on 7 October 2026, split into its parts.
| Crude oil (Brent at US$100.98 a barrel, A$1 = US$0.6965) | 91.2c |
|---|---|
| Refining, shipping, insurance, storage and wholesale margin | 72.1c |
| Fuel excise | 53.7c |
| GST (one eleventh of the price) | 21.7c |
| Wholesale price, national average | 238.7c |
| Retail costs and margin, typically | 10–15c |
| A fair pump price | about 249–254c |
The crude figure converts Brent from US dollars a barrel to Australian cents a litre, using 158.987 litres to the barrel. The second line is what is left once the other three are taken out. GST at the pump is a little higher than 21.7c because it is also charged on the retail margin.
Roughly a third of what you pay is tax, a third is crude oil, and most of the rest is the cost of turning that oil into petrol and getting it to Australia.
Crude oil
Australian fuel is priced off Brent, the North Sea crude that serves as the world's benchmark. It is quoted in US dollars a barrel, so what matters here is Brent in Australian dollars. On 7 October that was A$144.98 a barrel, or 91.2c a litre.
This is the most volatile part of the price. Brent averaged US$63.76 in October 2025 and US$101.93 in the first week of October 2026, after the conflict around the Strait of Hormuz. With the dollar a little stronger, that rise alone added about 31c a litre to the cost of fuel, or 34c once GST is counted.
Refining, shipping and the wholesale margin
Australia does not refine most of its own fuel. Only two refineries are left, Ampol's at Lytton in Brisbane and Viva Energy's at Geelong, so most petrol and diesel arrives by tanker, much of it from refineries in Singapore, South Korea and elsewhere in Asia. Wholesalers price it off the cost of refined petrol in Singapore, plus the cost of shipping it here, insuring it, storing it at a terminal and their own margin.
In normal times this slice is modest. In February 2026, before the crisis, wholesale petrol sat about 25c a litre above the cost of the crude it was made from. By October the gap was about 72c, because refined fuel became scarce faster than crude did. We look at that in detail in why wholesale fuel rose faster than oil this year.
Fuel excise
Excise is a flat amount per litre, the same for petrol and diesel, set by the ATO and raised in line with inflation every February and August. From 3 August 2026 it is 53.7c a litre. Because it is fixed, it does not grow when oil gets dearer, but it does make up a smaller share of the price when fuel is expensive and a bigger share when fuel is cheap.
Excise was cut to 20.6c from 1 April to 30 June 2026 and to 36.6c in July. What happened to wholesale prices on each of those days is in what the 2026 excise cut did to prices.
Businesses that use fuel off-road, such as farms and mines, can claim most of the excise back through fuel tax credits. Households cannot.
GST
GST is 10% of the price before GST, which makes it one eleventh of the price you pay. It is charged on everything above, including the excise, so you pay a little tax on a tax. At $2.50 a litre the GST is 22.7c.
The servo's margin
The difference between the terminal gate price and the pump price covers freight from the terminal, running the site, card fees and the retailer's profit. In the capitals it has typically been 10 to 15c a litre over time, which is why we use that range for a fair pump price. It is not fixed. In cities with price cycles the margin swings from close to nothing at the bottom of a cycle to well over 30c just after prices jump.
What a move in oil or the dollar does to the price
Two rules of thumb cover most weeks.
- Each US$10 a barrel on Brent is worth about 10c a litre at the pump, with the dollar near 70 US cents. US$10 is A$14.29 a barrel, which is 9.0c a litre, and GST takes it to 9.9c.
- Each one-cent move in the Australian dollar is worth about 1.4c a litre with Brent at US$100. A weaker dollar makes fuel dearer; a stronger one makes it cheaper.
Neither shows up immediately. Wholesale prices follow refined fuel prices in Asia, which follow crude, and the ACCC's rule of thumb is that a change in international prices takes one to two weeks to reach the pump. Retail prices tend to follow faster on the way up than on the way down.
What if oil or the dollar moves?
Compared with Brent at US$100.98 and the dollar at 69.65 US cents on 7 October 2026. It assumes refining and shipping costs stay where they are, which they often don't.
What this means when you fill up
- Watch Brent in Australian dollars, on our market page, rather than in US dollars. It tells you where wholesale prices are heading over the next fortnight.
- Check the terminal gate price for your city. Anything more than about 15c above it is more than a normal margin.
- Tax is a fixed 53.7c plus GST. At $1.30 a litre that would be half the price, which is where the idea that petrol is "half tax" comes from. At $2.50 it is about 30%.
Where these figures come from
Wholesale prices are the terminal gate prices published each weekday by the Australian Institute of Petroleum, which we hold back to 2004. The national figure is AIP's own average where it has published one, and our weighted calculation in between, which matches AIP's to within 0.1c. Oil and currency prices are delayed market closes. Excise rates are the ATO's. We check every figure against that data before publishing and correct mistakes in the update log. Spotted one? Email hello@thepetrolprice.com.