The Strait of Hormuz: One Fifth of the World's Oil, 21 Miles Wide

Before the 2026 closure, roughly 21 million barrels per day of crude oil and petroleum products — about a fifth of global consumption, and (per the IEA) about a quarter of seaborne oil trade — plus around a fifth of the world's LNG (nearly all of Qatar's exports). It is the single most important energy chokepoint on earth. Since 2 March 2026 actual flows have been far lower; see the timeline above.

Between Iran to the north and Oman/UAE to the south, connecting the Persian Gulf to the Gulf of Oman and the open ocean. At its narrowest it is only 21 miles wide, with two 2-mile-wide shipping lanes. Every barrel exported by sea from Kuwait, Qatar, Bahrain — and most from Saudi Arabia, Iraq, the UAE and Iran — passes through it.

Only partially. Saudi Arabia's East-West pipeline to the Red Sea and the UAE's pipeline to Fujairah together offer roughly 6–8 Mb/d of nominal bypass capacity — well under half of normal Hormuz flow, and both have their own vulnerabilities. In 2026 the IEA reported exports rerouted via Saudi Arabia's west coast, Fujairah and the Iraq–Turkey pipeline reaching about 7.2 Mb/d, up from under 4 Mb/d. Qatar's LNG has no bypass at all.

Iran's Revolutionary Guard declared the Strait of Hormuz closed on 2 March 2026, days after US–Israeli strikes on Iran began on 28 February, and tanker traffic collapsed. It was a near-total stoppage rather than a perfectly sealed waterway: the IEA puts flows at about 2.7 million barrels a day on average in March–May, against roughly 20 million before the war, and some vessels still passed under an Iranian-controlled permit arrangement. A ceasefire on 8 April and a US–Iran memorandum in mid-June partly reopened the strait, but attacks on ships and renewed hostilities on 7–8 July reversed much of that, and in their September reports both the IEA and the EIA still described flows as constrained. What is not settled: we have not found an agency count of daily transits after August, so none is quoted here. Source wording differs — "closed", "near-closure", "severely constrained" — because the strait was neither fully sealed nor normally open at any point since 2 March; the IEA and EIA volume figures are the ones used. Responsibility for individual attacks on ships, including those reported on 6 July, has generally not been confirmed by the governments involved.

As of the IEA's 11 September report (covering August) and the EIA's 9 September Short-Term Energy Outlook, flows through the strait remained constrained. The IEA put Gulf oil exports at about 13 million barrels a day in August, nearly half the pre-war level, with more than 10 million barrels a day of Gulf output shut in. The EIA estimated crude production shut-ins at 6.7 million barrels a day in August, up from 5.0 million in July; it assumes flows stay constrained through the fourth quarter of 2026 and that most production and trade take until the second quarter of 2027 to return to pre-conflict averages. The two agencies measure shut-in output differently, so their figures are not interchangeable.

Since 2 March 2026, when Iran declared the strait closed. The one significant reopening ran from mid-June, under a US–Iran memorandum, until attacks on ships and renewed hostilities on 6–8 July. In the IEA's report of 11 September, covering August, flows were still severely constrained — more than six months of disruption, with no agency figure yet showing a return to normal.

The IEA called the resulting loss of supply the largest in the history of the global oil market: flows fell from about 20 million barrels a day before the war to about 2.7 million on average in March–May. Brent futures peaked at $118.35 a barrel on March 31, 2026 in this site's cached daily history, and the IEA reported the physical North Sea Dated benchmark reaching an all-time high of $144 in early March. Before it happened, analysts' scenarios had put crude well above $150; the full price path is on the oil crises page.