The month in numbers
| National wholesale, c/L | Petrol | Diesel |
|---|---|---|
| 1 September | 196.0 | 236.7 |
| 30 September | 231.0 | 264.1 |
| Change over the month | +35.0 | +27.4 |
| September average | 216.7 | 256.2 |
| August average | 195.9 | 239.5 |
| Highest | 231.9 23 Sep | 276.1 22 Sep |
Petrol rose on 17 of September's 22 trading days. By the end of the month the national wholesale price was 18% higher than at the start.
What drove it
Brent crude averaged US$100.99 a barrel in September, up from US$88.24 in August, as renewed US–Iran strikes around the Strait of Hormuz from 9 September pushed it back above US$100 for the first time since late July. Saudi Arabia's East-West pipeline went offline in mid-September, removing one of the main routes that bypass the Strait. The Australian dollar was steady at about 71 US cents across both months, so the rise came through in full.
In Australian cents, Brent rose by 11.3c a litre on average between August and September. Wholesale petrol rose 20.8c on average, before counting GST about 18.9c. So roughly 7c a litre of September's rise was not crude at all but the extra cost of refined fuel, the gap we track in why fuel rose faster than oil in 2026. That gap for petrol widened from 46c to 54c a litre.
The steepest stretch was between 14 and 18 September, when national wholesale petrol rose 12.8c and diesel 20.2c. Diesel then turned. It peaked on 22 September and fell on each of the six trading days left in the month, finishing 12c below its peak, even as talk on 24 September of a possible US ban on diesel exports raised fears of a shortage. Petrol barely moved in the last week, then started rising again in early October.
City by city
| City | Petrol 30 Sep | Change in Sep | Diesel 30 Sep | Change in Sep |
|---|---|---|---|---|
| Perth | 228.7 | +34.0 | 257.2 | +26.1 |
| Adelaide | 229.1 | +34.3 | 263.1 | +27.2 |
| Melbourne | 230.8 | +35.6 | 264.2 | +25.6 |
| Brisbane | 231.7 | +34.7 | 267.1 | +28.8 |
| Sydney | 232.2 | +35.6 | 266.5 | +28.3 |
| Hobart | 234.6 | +35.4 | 265.3 | +27.7 |
| Darwin | 238.0 | +34.3 | 273.0 | +25.7 |
Terminal gate prices, cents a litre, from 1 to 30 September, from the Australian Institute of Petroleum.
The rise was almost identical everywhere, between 34c and 36c for petrol, which is what you would expect when the cause is international. Perth stayed the cheapest capital for both fuels, and Darwin the dearest, 9.3c above Perth for petrol and 15.8c for diesel.
What it meant at the pump
With a normal 10 to 15c retail margin, the fair pump price for regular unleaded across the capitals went from about 206 to 211c at the start of the month to about 241 to 246c at the end. For a household filling a 50-litre tank once a week, the month's rise adds $17.50 a fill, or about $900 a year if prices stay here.
Rises this fast also disturb the price cycles in the big cities. Servos raise prices to keep up with wholesale costs rather than waiting for the next jump, so the usual slide down never properly arrives. In a month like September, the useful question is how far a servo is above today's wholesale price, and our city pages answer it each weekday.
Into October
National wholesale petrol rose a further 7.7c in the first week of October, to 238.7c on 7 October, with Brent back near US$104. Diesel held steady at about 263c to 264c. The government has ruled out a second excise cut. What happens next depends mostly on the Strait of Hormuz and on whether refined fuel supply in Asia loosens; we will cover it in the October report in early November.
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.