Brisbane petrol and diesel after Brent hit US$110: how much, how fast

TL;DR: About 3.9 c/L. That is what Brent’s jump to US$109.86 on Friday 16 October is worth at the bowser if it holds and wholesale takes it in full. As of Sunday it isn’t in the Brisbane gate price, and Tuesday 20 October’s file is the first likely to show it. Diesel: if the gate takes all 3.9, my estimates put between almost nothing and about 3.6 c/L at the Brisbane pump within two weeks of the gate moving. Petrol: the pump has 3.5 c/L of cushion over wholesale, and the last rise like this mostly didn’t reach it.

“There is no good reason for fuel companies to be increasing their prices just days after conflict broke out… that usually takes around two weeks to flow through to bowsers here in Australia, not two days.” — Dr Ian Jeffreys, RACQ, March 2026

The question is back. On 16 October Brent touched US$110 for the first time since May and settled at US$109.86, up US$3.94 or 3.7% on the day and nearly 5% for the week, on Iranian attacks around the Strait of Hormuz and Ukraine’s vow to hit Russian refineries (CNBC, The National). It isn’t new territory for readers here. My 16 September post had Brent around US$109, and on 23 September I followed that surge into the diesel price.

The claim

Brent’s jump reaches your bowser in about two weeks. That is Jeffreys’ “around two weeks”. The other half of the question is how much: does it arrive cent for cent? I checked both.

What we checked

Two public series. The pump side is what Brisbane stations report to the Queensland Government feed: 438 stations within 30 km of the CBD reporting regular unleaded (91), 472 reporting diesel, taken as a daily median. The wholesale side is the Brisbane terminal gate price, or TGP, from the Australian Institute of Petroleum, GST included. Brent is from CNBC and The National; the exchange rate is the Reserve Bank’s daily rate.

The conversion works for any Australian driver. A barrel is 158.987 litres. At 69.47 US cents to the dollar (RBA, 16 October), US$1 a barrel is 0.91 c/L before GST, about 1.0 c/L with it. Friday’s move was US$3.94, so 3.9 c/L. Excise is a fixed amount per litre and doesn’t move with crude.

That 3.9 holds anywhere in Australia. Everything below about the gate price and the pump is Brisbane metro, within 30 km of the CBD, only. Regional Queensland is supplied from terminals AIP doesn’t publish, as I noted on 11 October.

What the data shows

It isn’t in wholesale yet. AIP says gate prices are “generally collated each weekday morning”. Friday 16 October’s Brisbane gate price was 235.4 c/L for unleaded and 264.8 for diesel, both set before Brent moved. The gate follows Singapore prices for refined fuel, and Singapore’s trading day ends before London and New York, where Brent settles. Monday 19 October’s file is collated before Singapore trades on Monday, so it can only carry what Singapore had priced by Friday’s close. Part of Friday’s rise may have come during Asian trading hours, so Monday’s file could show some of it. Tuesday 20 October’s is the first file that can realistically reflect the whole move. If Monday’s shows little, or only some of it, the trading hours are why. You can check both on AIP’s site yourself.

The gate doesn’t follow Brent directly. The plainest example is the past month. On 16 September Brent was around US$109 and the dollar 0.7133 (RBA): about A$153 a barrel. The next day’s Brisbane diesel gate price was 267.5. Friday’s 264.8 was set before the jump, with Brent near Thursday’s settle of about US$105.9 and the dollar at 0.6955: about A$152 a barrel. Same one-day lag both times, roughly the same barrel in Australian dollars, and a diesel gate 2.7 cents lower. Shift the September date and the answer moves: against the 16 September gate (262.7), Friday’s is 2.1 higher; against the 18th (273.1), 8.3 lower. The gate was climbing fast that week. The honest reading is that the same barrel has come with a diesel gate anywhere from about 2 c/L higher to 8 c/L lower, depending on the day.

After Friday, at US$109.86 and 0.6947, the barrel is about A$158. That is dearer than in September by about 3.7 c/L with GST, not the same. The week to 16 October doesn’t line up neatly either. Up to Thursday’s settle, the last close Friday’s gate could have seen, Brent was up only about 1% on the week, while the unleaded gate price fell 7.1 from its 12 October high of 242.5 and the diesel gate price was flat. I don’t hold a Singapore series, so I won’t guess why.

Brent may be the wrong ruler for diesel. Brent is crude. The IEA said wholesale diesel in Singapore passed US$200 a barrel this week (as reported by The National), so a cent-for-cent Brent figure may understate what the diesel gate does next.

The dollar cuts both ways, depending on the date. The RBA had the Australian dollar at 0.6947 US on 16 October. A year earlier, on 16 October 2025, it was 0.6492. Against that, the dollar is 7.0% stronger, and US$110 Brent costs about 7.7 c/L less with GST than it would at last year’s rate. The past month runs the other way. My 16 September post had the dollar at about 72 US cents; the RBA’s rate that day was 0.7133, so 72 was rounded up. From 16 September to 16 October it fell 2.6%, which adds about 2.9 c/L at US$110. That is close to Friday’s whole move, and it is a cost on top, not a cushion.

Diesel follows the gate, eventually. Week to week, Brisbane’s diesel median tracks the diesel gate price with a correlation of 0.88 since January 2025. In my July post on the lag it was 0.80, over a shorter window to 23 July; the three months since lift it. Unleaded’s is 0.19. The diesel pump sits 20.1 above its gate price. My 11 October post held that gap against three yardsticks, and it still depends which one you pick. Against the 22.7 I used in July, it is 2.6 under. Against the 20.5 median since January 2024, 0.4 under. Against the 19.0 median of the 30 days to 11 October, 1.1 over. None of the three shows a wide cushion to soak up a rise, and none shows a cut owed. I’m still not letting one win by default.

How fast it lands is uncertain. If the diesel gate takes the full 3.9, the July lag curve (a 13.8-day half-life) puts about 1.2 c/L at the pump after one week, 2.0 after two and 2.5 after three. A weekly re-run on the panel to 16 October puts 2.7, 3.6 and 3.9. Those are the two headline fits. Other windows spread both ways. The July post’s own window, re-run on today’s panel, gives an 11.6-day half-life (about 1.3, 2.2 and 2.8 c/L at one, two and three weeks). The window to 16 October gives 8.7 (about 1.7, 2.6 and 3.2). The window from 15 January 2025 to 30 June 2026 gives 30.3 (about 0.6, 1.1 and 1.5). That last one stops just before July, when the diesel gate went from 160.8 on 30 June to 213.4 on 23 July, including the 1 July excise step. A run of big one-way wholesale moves entering the window is the most likely reason the later fits come out faster. And the July post found that over a two-week look, up moves passed through roughly 0% while down moves passed through about 56%, on a thin sample. This is an up move. So at two weeks the range runs from close to nothing to about 3.6. On today’s 284.9 c/L metro median, and only if the gate takes the full 3.9, nothing else moves and the pump keeps its current 20.1 gap over the gate, that is somewhere between about 285 and 289 by early November. That gap is under the July yardstick, so it could also widen. The clock starts when the gate moves: Monday 19 October at the earliest, more likely Tuesday.

Petrol: 3.5 cents of cushion. Brisbane’s petrol cycle usually moves about 45 c/L from peak to trough (Dan’s July figure). It isn’t moving now. The regular unleaded median has sat between 236.9 and 240.9 since 19 September, and as I wrote on 11 October, no discount phase has started. The pump is 3.5 above its gate price, against a median gap of 15.7 since January 2024. A full 3.9 rise would lift the gate to about 239.3, 0.4 above today’s 238.9 median, and put the pump back under the gate price, as it was from 7 to 13 October. The last rise like this, 2 to 9 October, saw the gate go from 233.3 to 241.6 and the pump up 3.0, and the pump finished under the gate price. The gate is a published list price, though. Retailers may buy on contract and still be selling older stock, so being under it does not mean selling at a loss. Whether the pump holds back on a rise twice is the open question. Petrol’s week-to-week link to the gate is weak, so I won’t put a number on the pump. In a market this flat, though, 3.9 is about as wide as the whole month’s range.

The verdict

Partly true, and not yet. From the gate price, two weeks gets anywhere from almost none to nearly all of a diesel move to the Brisbane pump, depending on the fit; the July curve’s middle reading is about half, and rises have passed through slower than falls. Brent-to-gate adds at least a couple of trading days on top, which I can’t measure. On how much, it is cent for cent only if the gate takes the full move, and the gate follows Singapore, not Brent: the same barrel in Australian dollars has come with a diesel gate anywhere from about 2 c/L higher to 8 c/L lower than Friday’s, depending on the day. About 3.9 c/L if it holds, which is a big if. Risk premiums can unwind as fast as they arrive, and if this one does, the effect is close to zero. The risk runs the other way for diesel. With Singapore diesel past US$200, if refining margins widen on top of crude, the diesel gate can rise by more than the crude move.

What it means for your next fill

• Diesel: if the gate takes the full 3.9, that is $2.73 on a 70 L tank, spread over the next few weeks. The gap between the cheapest servo and the median today is $13.58, about five times as much. Where you fill is worth more than Friday’s oil move. On 50 L it’s $1.95 against $9.70.
• Petrol: if Friday’s move reached the pump in full, that’s $1.95 on 50 L, and the last rise like this mostly didn’t. With no cycle running there is no trough to wait for. The cheapest regular unleaded in Brisbane now is 223.5, at U-Go Park Ridge (reported 8.02am Sunday 18 October) and United Crestmead (reported 2.10pm Thursday 15 October). That is 11.9 under Friday’s gate list price and 15.4 under the 238.9 median, $7.70 a tank.
• Every price above is what stations report to the Queensland Government, not a crowd submission. The live list is on Pinly Fuel. Some stations last reported days ago, so check before you drive.

How we measured and honest limits:

• Grades. Unleaded is regular unleaded (91, ULP). Diesel is the diesel family: the cheapest of standard and premium diesel at each station, because many metro sites report diesel only under the premium code.
• The panel. Each station’s last reported price is carried forward if it was reported within the 45 days up to the end of that day, and the median is taken across stations within 30 km of the Brisbane CBD. The 1 March to 27 April 2026 data gap is excluded, as in my earlier posts. Gate prices are AIP’s Brisbane file to 16 October; weekends are carried at Friday’s.
• The speed estimates. The 1.2, 2.0 and 2.5 are the July error-correction curve. The 2.7, 3.6 and 3.9 are a weekly distributed-lag fit on the panel from 15 January 2025 to 16 October 2026. The half-lives of 11.6, 8.7 and 30.3 days are the same error-correction model re-run on today’s panel over three windows: 1 January 2025 to 23 July 2026 (the July post’s), 15 January 2025 to 16 October 2026, and 15 January 2025 to 30 June 2026. The c/L at one, two and three weeks follow from each half-life as 3.9 × (1 − 0.5^(days ÷ half-life)), and match the model’s own pass-through shares. Re-run on today’s panel for the July window, the weekly diesel correlation is 0.82, not 0.80. The 0% and 56% for rises and falls are from the July post and rest on 66 to 103 events a side. I can’t measure how long Brent takes to reach the gate price; I have no crude or Singapore history.
• Two kinds of correlation. Unleaded’s 0.19 here is a week-to-week correlation of price changes. The 0.13 in my July post was a correlation of price levels at a two-day lag. They measure different things, so the gap between them is not a change in the market.
• The diesel yardsticks. The 22.7, 20.5 and 19.0 are the three from my 11 October post. The 30-day window rolls: for the 30 days to 16 October the median is 21.0 (mean 19.7), against which 20.1 is 0.9 under. That doesn’t change the reading.
• The quote. Dr Ian Jeffreys of the RACQ said this in March 2026, about the price spike after conflict broke out then, not about this month’s move. I first quoted it in how the oil price reaches your bowser. It’s here for the timing claim only.
• The September comparison. The diesel gate was 262.7 on 16 September, 267.5 on the 17th and 273.1 on the 18th. I compare each barrel with the next day’s gate (16 September Brent with the 17th’s gate; Thursday 15 October’s with Friday’s), because the gate trails the barrel by at least a day. The US$105.9 is Thursday’s settle worked back from Friday’s 3.7% rise. The A$ barrel figures are Brent divided by the RBA rate for that day and are approximate.
• The Singapore timing. I don’t know any wholesaler’s pricing formula. “Tuesday, realistically” is my reading of the trading hours, not something AIP states, and the move could take longer to show.
• The petrol figures. The 45 c/L is Dan’s July figure, a median peak-to-trough drop of 46.5 across 12 swings. The 15.7 is the median pump-minus-gate gap since January 2024, as in my 11 October post. The 3.9 for petrol is a crude-cost bound, not a pump forecast. The gate price is an average of what wholesalers post for the day; I have no data on what any retailer paid.
• External figures. Brent’s settle, daily move and “first time since May” are from CNBC and The National, 16 October; the weekly “nearly 5%” and the Singapore diesel figure are from The National, citing the IEA. The dollar is the RBA’s daily rate (table F11): 0.6947 on 16 October 2026, 0.6955 on 15 October, 0.7133 on 16 September and 0.6492 on 16 October 2025. Through September it ran between 0.6977 and 0.7232, so the size of the fall depends on the day you start from; 2.6% is 16 September to 16 October. MTFX had Friday’s close at 0.6946. The c/L conversions include GST.
• The floors. Live prices pulled at 4:39pm AEST on Sunday 18 October, stations marked available only. They go out of date within hours. A station reports when its price changes, so an older timestamp is not a wrong price, but check before you drive. The chart’s dearest figure uses only stations that reported in the past week. If you’re reading this on Monday 19 October or later, AIP’s newer files may already have moved.

— Tom