Start with the metric that is easiest to grasp. Reuters calculations based on International Energy Agency data say the current conflict has cut more than 12 million barrels per day from supply, equal to 11.5% of global oil demand (DD India reported). That is the largest daily output loss on record. It is also larger than the peak losses in the 1973-74 Arab oil embargo, the 1978-79 Iranian Revolution, and the 1991 Gulf War combined, the IEA said (DD India reported).

That does not mean it is the largest energy shock ever in every sense. It means the daily hit to oil supply is unmatched. Change the metric, and the ranking changes with it.

The 1973-74 embargo peaked at a 4.5 million bpd cut, the Iranian Revolution at 5.6 million bpd, and the 1991 Gulf War at 4.3 million bpd, all according to IEA data cited by Reuters (DD India reported). Against those numbers, the current loss sits in another league.

The Strait of Hormuz is a narrow passage at the mouth of the Persian Gulf, and it is one of the world’s most important oil chokepoints. Think of it as the drain at the bottom of the Gulf. Close it, and crude from Saudi Arabia, the UAE, Kuwait, Iraq and Qatar has very few easy exits.

In 2023, oil flows through Hormuz averaged 20.9 million barrels per day, about 20% of global petroleum liquids consumption and more than one-quarter of seaborne oil trade worldwide, according to the U.S. EIA (U.S. EIA, June 2024). The same report says 83% of the crude oil and condensate moving through the strait went to Asian markets, with China, India, Japan and South Korea taking 69% of all Hormuz flows (U.S. EIA, June 2024).

That is why the shortages have shown up first in Asia and Africa, not in the places that usually dominate the oil-price conversation (DD India reported). A Hormuz closure is not targeted in the way the 1973 Arab embargo was. Back then, Arab producers aimed the cut at the United States and the Netherlands, and American motorists ended up queuing for gasoline. This time, the damage is broader and less selective. It lands hardest on import-dependent buyers, especially in Asia.

The United States is less exposed than it was in the 1970s. In 2023, it imported about 0.5 million bpd through Hormuz, equal to roughly 2% of U.S. petroleum liquids consumption (U.S. EIA, June 2024). That is not nothing, but it is a long way from the old gasoline lines.

The question of whether this is the worst shock in history depends on what kind of “worst” is meant. Oil markets have two ways of keeping score, and they do not always agree.

The 1973-74 Arab oil embargo

The embargo took three months to reach its full 4.5 million bpd cut, and it ran from October 1973 to March 1974. Reuters calculations put the cumulative loss at roughly 530 million to 650 million barrels (DD India reported). That puts it in the same neighborhood as the current crisis at the 52-day mark, when Reuters calculations say about 624 million barrels had been removed from the market (DD India reported).

The important difference is how the damage was absorbed. In 1973, other OPEC producers had meaningful spare capacity, and some of the gap was later filled by non-Arab output. A Hormuz closure is more stubborn. It is not a negotiated cut. It is a physical blockade of the route most Gulf exporters use.

The 1978-81 Iranian Revolution

The Iranian Revolution looks smaller if you focus on the peak, and larger if you focus on time. The IEA says the peak loss was 5.6 million bpd, below today’s disruption (DD India reported). But the production collapse lasted much longer. According to the U.S. Department of Energy, Iran’s crude output dropped by an average of 3.9 million bpd from 1978 to 1981, a shortfall Reuters calculates at about 4.27 billion barrels over three years, though much of that loss was compensated by Iran’s Gulf neighbours (DD India reported).

That is why the current crisis can be the biggest daily shock on record and still fall short on cumulative volume. Multi-year disruptions are tedious that way. They pile up.

The 1991 Gulf War

The Gulf War produced a smaller but still severe hit. Reuters calculations based on IEA data put the peak loss at 4.3 million bpd, lasting about four months, for a cumulative loss of at least 516 million barrels (DD India reported). By that yardstick, the current crisis is already larger.

The 2022 Ukraine war

Russia’s invasion of Ukraine triggered a global energy crisis, especially in Europe, where countries scrambled to reduce dependence on Russian oil and gas (DD India reported). Russian oil output fell by 9% in April 2022, or about 1 million bpd, according to the U.S. EIA, which is far smaller than the current disruption (DD India reported).

That comparison helps, but only up to a point. The Ukraine shock was a major energy crisis. This one is oil and gas at the same time.

That is the part oil-only comparisons miss. Every previous shock in this discussion was an oil shock. This one has also knocked out roughly a fifth of the world’s liquefied natural gas production in Qatar, according to Reuters calculations cited by DD India (DD India reported). Qatar first exported LNG in 1996, so there was no global LNG trade during the 1973 embargo or the Iranian Revolution to compare with in the first place (DD India reported).

That is why the IEA has described the conflict, combined with Europe’s still-unsettled gas market after Russia’s 2022 invasion of Ukraine, as the worst energy crisis the world has faced (DD India reported). That is the IEA’s judgment, not a verdict carved into stone. But it captures the point well enough: oil markets have seen disasters before. Oil and LNG together is a rarer beast.

For countries that import both fuels from the Gulf, especially across East Asia, the pressure is immediate and layered. Transport fuel, power generation and industrial gas supply are all under stress at once. That is a different kind of headache.

By recent standards, the oil market entered the crisis with a cushion. The IEA said global inventories rose by 477 million barrels through 2025, with OECD industry stocks moving above their five-year average for the first time since 2021. A further 49 million barrels were added in January 2026 (IEA, February 2026).

Supply was also expected to grow faster than demand. The IEA forecast world oil supply to rise by 2.4 million bpd in 2026 to 108.6 million bpd, while demand growth was projected at 850,000 bpd (IEA, February 2026). On paper, that looked like room to absorb a shock.

Then the shock arrived at more than 12 million bpd. At that pace, the entire 2025 inventory build of 477 million barrels would be burned through in roughly 40 days. That does not tell the whole story, because spare capacity, pipeline workarounds and reserve releases all matter too. But those figures have not been fully quantified in the source material, which is part of the problem. The market can count the barrels it has lost. It cannot yet see every barrel it might claw back.

So where does that leave the comparison? By daily output lost, the Iran war oil supply shock compared with past disruptions is simple, this one is the largest on record. By cumulative barrels, the Iranian Revolution still likely leads, and the 1973 embargo remains very much in the running. By fuel breadth, no past oil shock in this set matches the current hit to both oil and LNG.

That is the real answer, if an answer is what the reader came for. The crisis is already historic on one metric and still unresolved on another. What happens next depends on three things that matter more than slogans: how long the closure lasts, whether bypass capacity can be expanded, and whether LNG buyers can find replacements at scale.

For now, the safest comparison is also the most honest one. This is the biggest daily oil supply loss on record, and one of the few energy shocks that can plausibly be described as bigger than the last one before the market has finished counting.