Main version (about 260 words)
Iran says the Strait of Hormuz is closed until further notice. Your biggest diesel cost increase is still the one Canberra scheduled months ago.
The weekend sequence was ugly. On Saturday Iran struck a Cyprus-flagged container ship in the strait, leaving a crew member missing. The US answered with strikes on about 140 Iranian targets early Sunday, then a second night of strikes. Iran fired missiles and drones at Bahrain, Qatar and the UAE, and declared the strait closed until further notice.
Oil noticed. Brent settled at US$76.01 on Friday. Early Monday quotes have it above US$80, up around 5% before most Australian businesses opened their email. That is still well short of the US$120 wartime peak, but the direction has turned and the convoy bet that was holding prices down just lost.
Here is the part that should actually drive your pricing. A US$5 move in crude is worth roughly 4 cents a litre at the pump. The second half of the fuel excise restoration lands on 2 August and the ACCC puts the full restoration plus GST at up to 17.6 cents a litre. The war headline moves your costs by less than the tax change almost nobody is talking about. One is a maybe. The other is legislated, with a date.
So price both, but in the right order.
Index your fuel surcharge to terminal gate prices and review it weekly, because TGP will carry the crude move within days.
Write the 2 August excise step into every quote that survives past that date. Known number, known date.
Know your fuel burn per job, not per month.
Geopolitics is the variable. The excise step is the constant. Quote like it.
Short version (X or LinkedIn short form)
Iran has declared the Strait of Hormuz closed until further notice after a weekend of escalating strikes.
Brent settled at US$76.01 Friday. Early Monday it is above US$80.
But run the arithmetic. A US$5 crude move is worth about 4c/L at the pump. The excise step on 2 August adds up to 17.6c/L with GST.
The war is the headline. The tax change is the bigger line item, and it has a date.
Index your fuel surcharge to terminal gate prices, review weekly, and write 2 August into every quote now.
Price the arithmetic, not the headline.
Suggested first comment (sources)
Weekend events: Iran struck a Cyprus-flagged container ship in the strait on Saturday 11 July, the US hit about 140 Iranian targets early Sunday with a second night of strikes following, Iran attacked Bahrain, Qatar and the UAE and declared the strait closed until further notice (NPR, Washington Post, CNN, 11-12 July). Prices: Brent settlement 10 July US$76.01 (Reuters). Early Monday quotes above US$80 (Bloomberg, oilprice.com). Wartime peak of about US$120 earlier in the conflict per NPR. Excise and pump figures from the ACCC fuel monitoring update of 3 July 2026. Terminal gate diesel jumped 14.9c/L in a day when the first half of the excise cut was restored on 1 July.
Verify before posting
- Re-check the live Brent price immediately before posting. The "above US$80" figure comes from a delayed feed (oilprice.com showed US$80.57 with a one-day-delay notation) and Monday trading is moving fast. Adjust "up around 5%" to match the live number.
- Friday close discrepancy: the Reuters settlement was US$76.01 but The National reported US$76.54 late Friday. The draft uses the settlement figure. Keep one basis and do not mix them.
- The 4c/L per US$5 of crude conversion is approximate arithmetic (159 litres per barrel at about 0.65 AUD/USD) and ignores refiner margins and lags. It is presented as rough, keep it that way or drop the number and say "a few cents".
- Iran declaring the strait closed is a claim, not a verified physical blockade. CENTCOM has previously disputed closure claims and says it has facilitated large volumes of transit since May. "Says it is closed" is the accurate phrasing, do not write "the strait is closed" as fact.
- The March terminal gate spike claim (Melbourne TGP 165.6 to 295.1c/L between 3 and 24 March) comes from a single logistics company blog (Core Logistics). It is not used in the drafts above, cross-check against AIP historical TGP data before reintroducing it.
- The rule of thumb that every 5c/L of diesel adds about 1% to a fuel levy comes from the same source and was left out for that reason.
Notes
Updated 13 July morning after the weekend escalation. The original "market says calm" angle died when Iran declared the strait closed and Brent gapped up, the contrarian angle now inverts: everyone will talk about the war, the sharper point is that the scheduled excise step is still the bigger and more certain number for an SME. Original 11 July version is in page history if needed.