TL;DR: Diesel got hit harder than petrol this July, and it wasn’t your imagination. Here in Brisbane the metro diesel median is up 52.0 c/L since 30 June (179.9 → 231.9 on our daily panel), against ULP’s 36.0 (153.9 → 189.9) — so diesel rose about 16 c/L more than petrol locally. Nationally the ACCC reported the same shape: diesel up 41.4 c/L over the month against petrol’s 28.0 — a five-city monthly average, not a Brisbane number, so read it as “the same direction, hotter here”. Three things stacked: the fuel-excise relief step on 1 July, a rising crude and distillate leg on top, and Brisbane’s own cycle timing. The 1 July step shows up as a +15.2 c/L move in the wholesale price, consistent with the 16 c/L excise change measured ex-GST. The excise floor moves again on 1 August, when the current 16 c/L cut comes off and the bowser steps up about 17.6 c/L once GST stacks — it’s fixed, and you can’t dodge it by waiting for a cheap day. The live metro diesel median is 231.9 c/L, and the gap to ULP is 42.0 c/L. What you can still do: the diesel spread across nearby servos is 21.2 c/L within 4 km right now — about $28 on a 130 L ute tank — and no amount of policy touches that. Drive to the cheap one.
I drive a diesel D-Max, so when a tradie leans on the ute at the servo and says “mate, why’s diesel up more than petrol all of a sudden”, I get the question straight to the tank. One of you put it plainer than I could, in a review of the other app:
“Bad luck for Diesel owners who thought the better economy on Diesel would be great. An extra 50c/L wipes that out.” — ‘Pavlov’, Whirlpool
That’s the month in one line. Here’s what actually moved it, and what the 1 August date means for your next fill.
The claim
Diesel got hit harder than petrol this July, and it’s not one thing — it’s three things landing at once. Sorting them out matters, because two of them you can’t do anything about, and one you can.
What we checked
Brisbane metro — every station within 30 km of the CBD — using each station’s latest price reported to the Queensland Government feed. For the month’s move I carried each station’s last price change forward day by day (a LOCF daily panel) and took the median across stations, the same method the companion diesel piece uses; 473 stations quote a diesel that way, 440 quote ULP. Diesel here means the diesel family: standard plus premium diesel, because roughly 360 metro stations file a price under the premium-diesel code (180 file the plain code, 66 file both) — the same feed labelling I unpicked in the 1-August excise post. Read the standard code alone and you’d see far fewer stations and a wrong answer, so I union the two per station the way the app does. I ran ULP the same way as the petrol control, and lined both up against the Brisbane wholesale price — the Terminal Gate Price, or TGP — from 30 June to now. The national numbers (the ACCC’s month, the crude leg, the 1 July / 1 August excise change) are cited as given, not pulled from our feed.
What the feed shows
Diesel outran petrol, locally by about 16 cents. Since 30 June the Brisbane metro diesel panel median is up 52.0 c/L (179.9 → 231.9). ULP over the same window is up 36.0 (153.9 → 189.9). That’s the same shape the ACCC reported nationally — diesel +41.4, petrol +28.0 — but don’t equate the two figures: theirs is a five-city average over a fixed calendar month, ours is Brisbane-only and current, which is why ours runs hotter. Read ours as “in Brisbane right now” and theirs as “nationally over the month”. The live gap between the two fuels at the board today is 42.0 c/L — diesel 231.9, ULP 189.9.
One reconciliation, because this masthead ran a diesel number three days ago. On 24 July the economy post read the diesel board median at 225.9; our panel on the same day sits at 227.9, and carries forward to 231.9 on 27 July. So diesel isn’t up 6 cents in three days by magic — it’s the same wholesale-driven climb those posts described, read three days further along. On our panel diesel walks 179.9 (30 Jun) → 214.9 (20 Jul) → 227.9 (24 Jul) → 231.9 (27 Jul), and ULP grinds up its cycle to a fresh peak alongside it. No cycle trough has landed to pull petrol back down yet, which is why both keep reading higher.
The excise step is the one clean-ish piece. On 1 July the fuel-excise relief stepped, and it shows up sharp in the wholesale price: Brisbane diesel TGP went 160.8 → 176.0 c/L in a single day — a +15.2 c/L wholesale move, consistent with the 16 c/L excise change measured ex-GST. Keep two numbers separate here, because they get muddled: the excise change is 16 c/L ex-GST (which is what shows in a wholesale price like the TGP), and the same change at the bowser is about 17.6 c/L once GST stacks on top. The 1 July step and the 1 August step are two halves of the same 16 c/L ex-GST measure — so they carry the same ex-GST magnitude, and both land as roughly 17.6 c/L at the pump. I’m not calling that +15.2 a clean excise readout, though: a single-day wholesale move also carries ordinary daily noise, so read it as a +15.2 c/L wholesale step consistent with the 16 c/L ex-GST excise change, not a pure meter reading of it. After that step it’s a steady crude-and-distillate climb: 176.0 on 1 July up to 217.0 by 24 July. That’s the chart below.
Retail followed wholesale, not a cheap Tuesday. Diesel doesn’t run the petrol sawtooth, so the day-of-week timing trick that works for petrol is weak here — retail and TGP rise and fall together, with the pump lagging wholesale by a couple of weeks (the wholesale-lag post measures that drag). That’s why “wait for the dip” is petrol advice: diesel has no weekly dip to wait for, it just drifts with wholesale. It still moves — I’m not saying diesel never changes — but it moves with the barrel, not the calendar.
The three forces, honestly. The 52 c/L local move is excise (the +15.2 c/L wholesale step on 1 July, consistent with the 16 c/L ex-GST excise change), plus rising crude and distillate, plus wherever Brisbane sits in its own cycle. I can attribute the excise slice to policy. I can’t cleanly split the rest at the bowser, and I won’t pretend to. And one more: the crude leg has a one-to-two-week lag to the bowser, so part of the recent jump is the July crude rise still working through, with more possibly still to land.
The verdict
Diesel got hit harder because three things stacked in one month: a policy step, a crude climb, and cycle timing — and diesel, tracking wholesale directly, took the crude leg full in the face while petrol’s discount cycle softened its month. The 52 c/L here (41 nationally) is real and mostly here to stay while wholesale sits high.
So what does that mean for your tank?
Two of these you can’t beat. The excise portion is fixed policy, and it moves again on 1 August, when the current 16 c/L cut (ex-GST) comes off and the bowser steps up about 17.6 c/L once GST stacks — I’ve done that tank maths in full in the 1-August excise post. That’s a dated fact, not a reason to panic-fill: the excise step is the same at every servo and can’t be dodged by timing. Topping up a day early saves you nothing on that piece.
What you can still beat is the spread across servos, and on a diesel tank it’s the whole game. For each metro station I take the gap between the dearest and cheapest diesel among its neighbours, then the median of those per-station spreads. Within 4 km of a typical metro station (median about 17 neighbours) that spread is 21.2 c/L right now — about $28 on a 130 L ute, $32 on a 150 L long-range or caravan rig. Widen to 10 km (median about 84 neighbours) and it’s 27.8 c/L, roughly $36 to $42 a fill. Metro-wide, cheapest to dearest is 203.9 versus 256.0 — 52.1 c/L apart. That spread is bigger than a fortnight of wholesale drift, and no policy or barrel move touches it. Pick diesel on fill.pinly.com.au, see the spread on the map, drive to the cheap one — and every price there is the one that station reported to the Queensland Government feed, not a stranger’s guess at the bowser (the exact thing that gets you caught out).
One honest limit
The 52 c/L local move blends three forces I can’t split cleanly at the pump — I’ve pinned the excise slice to the +15.2 c/L wholesale step on 1 July (consistent with the 16 c/L ex-GST excise change), and left the rest to the market, and even that step carries some ordinary daily wholesale noise on top of the excise. The ACCC’s 41.4 c/L is a five-city monthly average, ours is Brisbane-metro current: they’re consistent in direction, not the same number, so don’t read one as contradicting the other. The 225.9 board read from the 24 July post and this post’s 231.9 panel are a board-to-panel and three-days-later read, not a fresh jump — same wholesale climb, further along. The tank-dollar figures assume a 130 L ute and a 150 L rig — an assumption, not measured off your fills. And the July crude leg may still have more to land after this window closes.
Scope: Brisbane metro (473 stations within 30 km of the CBD reporting fresh diesel on the daily panel; the live board read on 27 July had 469 quoting diesel and 428 ULP), diesel family (standard + premium diesel) with ULP as the petrol control, Queensland Government price feed. The month’s move is a LOCF daily panel median, 30 June to 27 July 2026; live board reads are the latest price each station reported, sentinel prices above 400 c/L filtered out. Wholesale is the Brisbane-region Terminal Gate Price for diesel. Local spreads are per-anchor max-minus-min across neighbours within 4 km (median ~17 neighbours) and 10 km (median ~84), then the median of those spreads. National macro items — the ACCC’s report, the crude leg, the 1 July / 1 August excise change — are cited as given, not derived from our feed. The March–late-April 2026 data gap sits outside every window used here.