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Investigation

Strait of Hormuz: The Arithmetic of Closure

The question everyone in energy asks and nobody in the West will answer on the record: what does a Hormuz closure actually cost? We ran the arithmetic ourselves. Twenty million barrels a day through one 33-kilometre throat — spare capacity, shadow fleets, and the insurance math nobody wants to do out loud, done here in full.

The Strait of Hormuz seen from space

Key findings

  1. About 20.9 million barrels a day crossed Hormuz in the first half of 2025 — roughly 20% of everything the world burns, drives, and flies on. US Energy Information Administration
  2. At its narrowest the strait is 33 kilometres wide, squeezing traffic into lanes a few kilometres across each way. This is geography, not infrastructure — it cannot be rebuilt elsewhere. UK Hydrographic Office charts
  3. About a third of the world's seaborne crude trade and a fifth of its LNG pass through this one waterway. IEA; GIIGNL
  4. The two bypass pipelines can carry only about 4.7 million barrels a day — under a quarter of normal flow. Five producers, ~14 million barrels a day of it, have no bypass at all. EIA; ADNOC; Saudi Aramco
  5. 84% of the crude and 83% of the LNG goes to Asia. A Hormuz disruption is, arithmetically, an Asian energy crisis with European aftershocks. EIA 2024 analysis
  6. The 2026 disruption already repriced everything: Hormuz flows fell from 21.6 to 4.9 million b/d between late 2025 and mid-2026, while Brent rose 30.8% and US pump prices 36.4%. EIA; market price data
  7. Spare capacity that must transit Hormuz is not spare at all — the circularity the market still refuses to price. Bureau analysis

The world economy has a throat. It is 33 kilometers wide.

At its narrowest, the Strait of Hormuz squeezes shipping into lanes roughly three kilometers across in each direction. Through them flows about twenty million barrels of petroleum liquids every day.

That is roughly a fifth of everything the world burns, drives, and flies on.

It is also the corridor for a large share of global liquefied natural gas — most of Qatar's output, which alone accounts for around a fifth of world LNG trade.

Figure 1 · Geography

The world's most expensive 33 kilometres

Schematic of the Strait of Hormuz. The traffic separation scheme runs between Iranian and Omani waters; the lanes are a few kilometres wide each way.

IRAN OMAN Persian Gulf Gulf of Oman ~33 km at narrows outbound ~3 km inbound ~3 km daily flow (H1 2025) 20.9M b/d ~34% of seaborne crude ~20% of world liquids use
Facilities get repaired. Geography does not negotiate: the lanes, the narrows and the traffic separation scheme are permanent. UK Hydrographic Office; EIA.

Iran has threatened to close the strait for decades. It never has. The threat is the instrument — and it works.

Every escalation reprices risk instantly. War-risk insurance premia for Gulf transits spike with each incident: after the 2019 tanker attacks in the Gulf of Oman, underwriters pushed rates sharply higher, and some owners simply refused the voyage.

The arithmetic of the only door

The Red Sea gave a live rehearsal. Houthi attacks on shipping from late 2023 forced container lines and then tankers around the Cape of Good Hope — adding weeks, burning fuel, snarling schedules.

Hormuz would be worse by an order of magnitude. There is no Cape to go around. The strait is the only door.

Almost. Two bypasses exist, and the arithmetic of both is sobering.

The UAE's Fujairah pipeline carries crude from Habshan to the Gulf of Oman — about 1.5 million barrels a day of nameplate capacity, bypassing the strait entirely.

Saudi Arabia's East-West Petroline runs to Yanbu on the Red Sea, with nameplate capacity around five million barrels a day — though it has rarely run anywhere near full.

Combined, the EIA estimates the two systems at roughly 4.7 million barrels a day of realistic bypass — and as little as 2.6 million of that is genuinely spare on a given day. Against twenty million of flow. The math does not close.

Chart 1 · Bypass arithmetic

Less than a quarter of Hormuz flow could go around it

Normal daily flow vs. maximum pipeline bypass capacity (EIA estimates, H1 2025)

Normal flow 20.9M b/d Max bypass 4.7M b/d ~22% could reroute at most Saudi East-West Petroline + UAE Fujairah line, combined EIA estimate
Five producers — Iraq, Kuwait, Qatar, Bahrain, Iran — have no pipeline bypass at all: about 14 million barrels a day with no second door. EIA; ADNOC; Saudi Aramco.

Then the spare-capacity question. OPEC's usable spare capacity sits mostly in Saudi Arabia and the UAE — commonly estimated at a few million barrels a day combined, and the true number is one of the industry's guarded secrets.

Spare capacity that must itself transit Hormuz is not spare at all. That is the circularity nobody prices.

Asia is the exposed flank. China, India, Japan, South Korea: the great importers of Gulf crude. A Hormuz disruption is, arithmetically, an Asian energy crisis with European aftershocks.

The price rehearsal of 2026

In 2019, the Abqaiq attack knocked out half of Saudi output for days. Brent jumped about 20% intraday — the largest one-day move on record at the time.

Abqaiq was a facility. Hormuz is a geography. Facilities get repaired. Geography does not negotiate.

The 2026 conflict turned the arithmetic into observed fact. Between the fourth quarter of 2025 and the second quarter of 2026, EIA-tracked flows through Hormuz collapsed from 21.6 to 4.9 million barrels a day. The global system rerouted what it could — Bab el-Mandeb flows rose from 5.4 to 8.1 million b/d — and the price did the rest.

Chart 2 · Price transmission

The shock reached the pump in weeks

Brent crude and US regular gasoline around the 2026 Hormuz disruption (EIA price data)

Brent, $/bbl $71.32 $93.26 +30.8% US gasoline, $/gal $2.937 $4.006 +36.4% Brent: 27 Feb → 11 Aug 2026 · Gasoline: last pre-disruption weekly release → peak
Notably, medium-term inflation expectations did not break — the shock stayed an energy shock and a household fuel bill. Central banks that treated every oil spike as generalized inflation would have answered a broader question than the data showed. EIA price data.
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You have read the key findings and the full bypass arithmetic. The rest of the investigation — the part that makes it an investigation — is behind the lock.

  • The full 3-lens analysis: Western, Eastern and Global South readings of the 2026 disruption
  • The unpublished war-game sequence: day one, week one, month one of a Hormuz closure
  • The consensus ledger: what all three blocs agree on, and what they don't
  • The methodology note and the complete 16-source appendix
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