Explainer: Where your $100 petrol fill-up actually goes
Petrol prices begin with crude oil, but that is only the start. Benchmark Analytics traces a $100 fill-up through refining, shipping, wholesale terminals, tax and the service station.
At the current average price across Australia's five largest cities, $100 buys about 45 litres of regular unleaded petrol. But the money does not simply go to the service station.
The price is built through a chain stretching from the international crude-oil market to an Australian petrol pump.
Start with crude oil. In the week to 9 September, Brent crude was equivalent to about 93 Australian cents per litre. On our $100 fill-up, that represents approximately $41.82. Brent is a benchmark rather than the literal crude barrel from which each litre of Australian petrol was produced, but it provides the upstream reference price.
Crude must then be refined into petrol. Australia's relevant benchmark is Singapore Mogas 95, which was about 114 cents per litre in that week. The 21-cent difference between Brent and Mogas — around $9.44 of our $100 — is the international refining spread. It reflects the market value added in converting crude into petrol and changes with refinery capacity, petrol demand and crude supply. It should not be interpreted as Australian refinery profit.
Next comes the import and wholesale chain. The petrol must be shipped or supplied domestically, meet Australian fuel specifications, insured, unloaded, stored and moved through terminals. The ACCC's wholesale category includes international shipping, fuel-quality premiums, insurance and losses, wharfage, terminal operations and wholesale marketing margins. Public data do not reliably separate those individual items. On the current numbers, this combined component is approximately $8.83 per $100.
Then government enters the price.
Fuel excise has been fully restored to 53.7 cents per litre. That represents about $24.15 of a $100 fill. GST adds another $9.09, because GST is one-eleventh of the final GST-inclusive price. Together, Commonwealth taxes account for approximately $33.24 of the $100.
Finally comes the journey from the terminal to the motorist. Terminal-gate prices exclude transport to the service station and retail operating costs. The residual must fund road transport, service-station wages, rent, electricity, administration and other operating costs — plus retailer profit. Using a seven-day wholesale lag gives this final retail-stage bundle an estimated $6.68 per $100.
That last figure is emphatically not a $6.68 retailer profit. The ACCC's longer-run gross retail measure includes both costs and profit, and can move substantially with petrol-price cycles and the timing of wholesale price changes. In 2025, for example, the five-city average gross indicative retail difference was 16.3 cents per litre.
The striking conclusion is that the service station controls only the final part of the chain. International crude and refining markets account for roughly half the current $100 fill, taxes about one-third, with wholesale logistics and the domestic retail system accounting for the remainder.