1. If the Strait of Hormuz stays shut, how long do Europe's emergency stocks hold out?
On paper, from 240 days for Greece, the most exposed country in the calculator with a Gulf share of 42.5%, to several years for countries that buy little from the Gulf, such as Germany (6.0%, 1,528 days), assuming all seven Gulf suppliers stop and nothing replaces them (our calculation, starting 23 September 2026). Every row below is exactly what the calculator returns for the same country and scenario, as long as you leave the stock field as it is.
| Country | Stock days (Eurostat) | Scenario | Net loss | Reach | On paper until |
|---|---|---|---|---|---|
| Greece | 101.841 (June 2026) | all seven Gulf states stop, nothing replaced | 42.5% | 240 days | 21 May 2027 |
| Poland | 91.557 (June 2026) | all seven Gulf states stop, nothing replaced | 37.0% | 247 days | 28 May 2027 |
| France | 87.873 (June 2026) | all seven Gulf states stop, nothing replaced | 20.1% | 437 days | 4 Dec 2027 |
| Italy | 89.710 (June 2026) | all seven Gulf states stop, nothing replaced | 16.1% | 557 days | 2 Apr 2028 |
| Austria | 88.434 (July 2026) | all seven Gulf states stop, nothing replaced | 10.8% | 819 days | 20 Dec 2028 |
| Spain | 97.062 (June 2026) | all seven Gulf states stop, nothing replaced | 11.7% | 830 days | 31 Dec 2028 |
| Germany | 91.688 (June 2026) | all seven Gulf states stop, nothing replaced | 6.0% | 1,528 days | about 4.2 years |
| Belgium | 109.511 (July 2026) | all seven Gulf states stop, nothing replaced | 4.6% | 2,381 days | about 6.5 years |
| France | 87.873 (June 2026) | all seven Gulf states stop, half replaced | 10.05% | 874 days | 13 Feb 2029 |
| Germany | 91.688 (June 2026) | all seven Gulf states stop, half replaced | 3.0% | 3,056 days | about 8.4 years |
| Germany | 91.688 (June 2026) | all imports stop | 100.0% | 92 days | 24 Dec 2026 |
| Germany | 91.688 (June 2026) | all imports stop, half replaced | 50.0% | 183 days | 25 Mar 2027 |
Our calculation, with the same method and data as the calculator, starting 23 Sep 2026; the date is the start plus the rounded number of days. Stocks: Eurostat nrg_stk_oem, latest month; Gulf share 2025: GOS Hormuz Index (Eurostat nrg_ti_oilm, our calculation). Beyond 1,095 days (three years) the calculator shows years instead of a date.
You will not find a British or American row, because Eurostat publishes no emergency stock days for either country. The UK counts its stocks in tonnes: 10.2 million tonnes at the end of the first quarter of 2026, which the government describes as “more than meeting” the IEA's requirement of 90 days of net imports, without giving an exact day figure (DESNZ). The US measures its Strategic Petroleum Reserve in barrels, 285.0 million in the week to 11 September 2026 (EIA), tracked on the US SPR level page. The US buys little Gulf crude, 7.9% of its crude imports in 2025 (EIA, our share); the UK is more exposed on jet fuel, 35% of which came from Kuwait (DESNZ). The details are on where UK and US oil comes from.
2. How do I use the Hormuz calculator?
Choose a country and a scenario, then, if you like, say how much of the lost oil is replaced and how far demand falls: the calculator divides the stock days by the net share lost and gives the reach in days, plus a date when the result is under about three years. It opens on Germany with all seven Gulf suppliers cut off.
The scenario menu offers:
- All seven Gulf states stop (the default), the upper bound for a closure of the strait;
- Suppliers with no bypass route stop, meaning Kuwait, Qatar, Bahrain and Iran;
- Gulf share as in Q2 2026, what the chosen country still took from the Gulf between April and June 2026;
- All imports stop, the extreme case;
- Your own value for the share lost.
For Germany the stock field reads 91.7, the Eurostat figure of 91.688 days rounded to one decimal place. Leave it alone and the calculation uses the exact value, which is why it matches the table; type a new number and that number is used instead. Under the result you get the no-imports case, the GOS Hormuz Index values for the country and a note on what the calculation leaves out. Dates run from the day you use the tool, while the examples on this page start on 23 September 2026. Fifteen EU countries are included, and nothing you type is stored or sent. Ireland, the only English-speaking country on the list, is a special case: it reported no crude, diesel or jet fuel imports straight from the Gulf in 2025 (0.0%), so in the Gulf scenarios the calculator reports that nothing is lost, and its 81.061 days of stocks (June 2026) only matter in the all-imports case.
3. What formula does the calculator use?
Reach in days = stock days ÷ net loss, where net loss = share lost × (1 − share replaced) − demand reduction. Greece shows how it works:
- Greece held 101.841 days of emergency stocks in June 2026 (Eurostat).
- In 2025, 42.5% of its crude, diesel and jet fuel imports came from the seven Gulf states. With nothing replaced and no cut in demand, the net loss is therefore 42.5%.
- 101.841 ÷ 0.425 ≈ 240 days. Counted from 23 September 2026, that takes you to 21 May 2027.
Replacement shrinks the loss and stretches the reach. If every import stopped but half came back through other routes, Germany's net loss would be 100% × (1 − 0.5) − 0 = 50%, and 91.688 ÷ 0.5 ≈ 183 days, to 25 March 2027.
Both inputs are official statistics. The share lost is the GOS Hormuz Exposure Index, our calculation from Eurostat's nrg_ti_oilm trade data: the weight share of Saudi Arabia, Iraq, the United Arab Emirates, Kuwait, Qatar, Bahrain and Iran in a country's 2025 imports of crude oil, diesel and heating oil, and jet fuel. Only the first three can send some of their oil around Hormuz by pipeline. The stock days are Eurostat's nrg_stk_oem series (updated 10 September 2026), counted under EU Directive 2009/119/EC as the greater of 90 days of average daily net imports or 61 days of inland consumption in the previous year; the 90-day rule page explains the details. Demand reduction comes off in percentage points of imports. The closest official yardstick uses a different base: under the Agreement on an International Energy Program (IEP), the IEA's founding treaty, members must be able to cut final consumption by 7% at a first stage.
4. Why do the results look more reassuring than the situation?
Because the calculator measures volumes, while a Hormuz closure hits Europe first through prices: according to the IEA, only around 600,000 barrels a day, or 4% of the exports through the strait, went to Europe before the crisis, against 80% to Asia (February 2026). Four things the reach figure leaves out:
- The world market. Nearly 15 million barrels of crude a day passed through the strait in 2025, nearly 34% of world crude trade. When that oil goes missing, buyers in China, India, Japan and Korea compete for the same cargoes as refiners in Europe and the US. In September the IEA put the loss of crude exports at just below 45%, held down by bypass routes and US military escorts.
- The product mix. France bought 59.8% of its imported jet fuel from the Gulf in 2025, and the UK took 35% from Kuwait alone, a supplier with no bypass route. Eurostat records the country that ships a cargo, not the origin of the crude inside it, so diesel refined in the Netherlands from Gulf crude counts as Dutch. Stocks by product are on the diesel and jet fuel stocks page.
- Burden sharing. For the 2026 collective action, 30 IEA members pledged 426 million barrels, the US 172.2 million (IEA, 19 March 2026). According to the US Department of Energy, the US share of such actions follows its share of oil consumption across IEA members, 42.3% as of December 2022; for the US, then, the yardstick is consumption, not exposure to the Gulf. Stocks can therefore fall in countries that lose few imports, and the calculator does not show that.
- Logistics. Delivery times and minimum levels in tanks and pipelines are not modelled. The counting rules cover part of this: the EU directive deducts 10% of stocks as unavailable (so does the IEA), and Eurostat's day counts follow the directive.
5. What happened to supplies and stocks in 2026?
On both sides of the Atlantic, imports kept flowing and emergency stocks fell anyway: the Gulf's share of EU countries' imports dropped from 13.2% in 2025 to 7.6% in the second quarter of 2026 (Eurostat, our calculation), and governments drew on their reserves for the IEA collective action. The US shows the pattern most clearly. The Persian Gulf share of its crude imports fell from 10.0% in January to 1.9% in June (EIA, our shares), yet its Strategic Petroleum Reserve dropped to 285.0 million barrels in the week to 11 September, the lowest level since 1982 according to Reuters. The US pledge of 172.2 million barrels to the IEA comes entirely from public stocks (IEA).
In Europe, EU countries imported 116,709.4 thousand tonnes of crude in the second quarter, a little over a quarter of the 455,847.4 thousand tonnes they took in 2025. The US became Germany's largest crude supplier in that quarter with 23.3%, while Kuwaiti jet fuel stopped reaching France: 2,730 thousand tonnes in 2025, none in the second quarter of 2026. Saudi Arabia kept supplying 45.3% of Poland's crude, consistent with a bypass via the East-West pipeline to the Red Sea, although Eurostat does not record the loading port. Stock days fell anyway, from 95.169 in March to 91.688 in June in Germany and from 94.527 to 87.873 in France. Every EU country's figure is in the Oil Reserves Monitor, and what makes sense for your own home is on the household energy reserve page.
How to cite: Global Oil Shock (Jörg Dässler), “Hormuz Scenario: How Long Would Oil Stocks Last?”, as of 23 Sep 2026, https://globaloilshock.com/en/strategic-oil-reserves/hormuz-scenario-calculator/