Oil price impact, explained.

The 17 million barrels a day that go through the strait.

Roughly 17 million barrels of crude oil and condensate transit the Strait of Hormuz every day in normal conditions, alongside roughly 3 million barrels per day of refined product, for about 20 million barrels of total liquids. That is about a fifth of total world oil consumption and about a quarter of all seaborne oil trade. The numbers move with seasonal demand and OPEC quota cycles, but the rough magnitude is the load-bearing fact.

When the strait closes, the question is not whether all 17M barrels stop moving; they don’t, because pipeline bypass capacity and Gulf-of-Oman terminals keep some volume flowing. The question is what fraction strands, and for how long.

The pipeline math says combined non-Hormuz nameplate is around 8.85M bpd (Petroline 7, ADCOP 1.5, Goreh-Jask ~0.35). Even at full utilization that’s only about half of normal Hormuz throughput, so at least 8M bpd strands with every line running flat out. Petroline (East-West Pipeline) is offline right now, so the lines are moving only about 1.64M bpd between them and far more than 8M bpd is stranded. That is the size of the supply disruption the market has to clear.

Three layers of price response.

Layer one: risk premium. The first thing Brent does when Hormuz news breaks is build a risk premium: a spread between the spot price and the implied price absent the disruption. Historically this premium has run anywhere from $5 to $25 a barrel depending on whether the market judges the closure to be days, weeks, or open-ended. Insurance prices the same risk simultaneously; the two markets move together.

Layer two: physical scarcity. If the closure persists past the inventory-cover horizon (60 to 90 days at normal demand), the market shifts from pricing risk to pricing actual scarcity. At that point the price has to do real work: it has to pull non-Gulf production into the market (US shale flexes up, Brazil and Guyana lift to capacity, OPEC cohort excluding the constrained members increases output), and it has to ration demand. Both responses are slow. Refiners don’t switch crude diets overnight; consumers don’t cut driving without sustained price pain.

Layer three: refined product crack. Brent is the input; gasoline, diesel, and jet fuel are the outputs. The spread between crude and product (the “crack spread”) widens when refiners face uncertainty about crude supply or quality; a Hormuz closure typically does both, because it disproportionately affects medium-sour crudes that many Asian and European refiners are configured for. The crack widening pulls retail fuel prices higher even before the crude price fully reprices.

How fast it shows up at the pump.

US retail gasoline averages reflect Brent moves on roughly a two-to-four week lag. The mechanism is a chain: spot crude → wholesale refined products (RBOB futures, jet fuel, diesel) → terminal rack prices → station retail. Each link adds a few days, and the chain is buffered by inventories, hedges, and contracted volumes that price ahead.

What that means in practice: a $20-a-barrel Brent move from the start of a closure can show up as roughly 50 cents a gallon at the US pump within three weeks. The first week shows wholesale movement that consumers don’t see; the second week shows it at the rack; the third week shows it at the station. The relationship is not perfectly linear and gets non-linear when refiners hit utilization or feedstock constraints, but the rule of thumb is reasonably stable.

In Europe and Asia the lag is shorter and the political pass-through is faster: many EU members tax fuel as a percentage rather than a fixed amount, so a Brent move translates more directly to retail. Asian markets that import most of their crude (Japan, Korea, Taiwan) feel a closure disproportionately because they have the least flexibility on feedstock.

Brent versus WTI: the spread that opens up.

Brent is the global benchmark. WTI is the US benchmark, priced at Cushing, Oklahoma: landlocked, sourced from US production, largely insulated from Gulf disruption. When Hormuz tightens, the Brent-WTI spread widens because Brent is repricing the global supply shock and WTI is repricing the smaller US-only view of it. A widening spread is one of the cleanest leading indicators that the market views Hormuz as a real and persistent disruption.

We surface this as an input to the Escalation Forecast, where it is labelled the Brent–WTI spread. In peacetime it floats around $2 to $4. During an active Hormuz closure it tends to sit at $5 to $10 or more. Both legs are taken on the later shared delivery month: Brent rolls about three weeks ahead of WTI, so differencing each crude’s own front month would price the calendar rather than the crude.

What we watch.

On Straits, the live oil-price reading is the largest figure on the homepage for a reason. It is the indicator most users will quote in the first hour of any escalation, and the one we most carefully tie to a real upstream: intraday front-month Brent and WTI futures (read from Yahoo Finance chart data, refreshed every ten minutes), with the EIA daily close as a guarded backstop that writes only when the intraday feed has been silent for more than two hours. One percentage change is shown, against the price 24 hours earlier, or against the previous session’s close when the market was shut in between. It is colour-tagged as alert when the move exceeds 3%. The methodology page documents the source chain.