Strait of Hormuz Throughput & Implied Oil Flow Explained
No single agency measures oil flowing through the Strait of Hormuz in real time. What gets reported as “implied flow” is an estimate — built from vessel tracking data, tanker draft, and historical loading patterns — and different trackers currently disagree by more than double.
Current Estimates vs. Baseline
What Does “Implied Flow” Mean?
No customs authority or port logs every barrel that crosses the strait in real time. Instead, analysts infer (“imply”) how much oil is moving by combining several proxy signals: how many tankers transited, how deep each vessel was sitting in the water (its draft, which indicates how full it is), the vessel's known cargo capacity in deadweight tonnage (DWT), and its declared or historical loading port.
“Implied Hormuz flow” is therefore a modeled estimate, not a direct measurement. It is the best real-time proxy available — official trade statistics lag by one to two months — but it means every headline number carries a methodology behind it, and that methodology is exactly where estimates start to diverge.
How Throughput Is Actually Measured
AIS Vessel Tracking
Ships broadcast position, speed, and course via the Automatic Identification System (AIS). Satellite and terrestrial receivers log every transit, giving a raw vessel count. Weakness: GPS spoofing and AIS “dark” periods (transponders switched off) undercount actual traffic during a crisis.
Draft-Based Load Estimation
A tanker riding low in the water is carrying more cargo. Providers like Kpler and Vortexa combine draft readings with each vessel’s known DWT to estimate how full it is, then sum across all transiting tankers to estimate total barrels.
Port & Terminal Nomination Data
Loading schedules and terminal nominations from Gulf export terminals (published or leaked) give analysts a forward-looking view of intended exports — useful for the days-ahead forecasts referenced in trading circles.
Government Claims
Government figures (e.g., the US Department of Energy) are typically compiled from a mix of the above plus classified intelligence sources. They are not independently auditable in real time, which is why they can diverge sharply from commercial trackers.
Why the Numbers Don't Agree
As of August 2026, published estimates of current Hormuz flow span a wide range, and the gap is itself a story:
Competing Figures
A more than two-fold gap between the lowest and highest published estimates reflects real methodological differences, not just rounding. Independent commercial trackers rely on observable vessel behavior; government figures can incorporate intelligence sources that aren't public, but also carry incentive to shape the narrative around sanctions, negotiations, or military posture. Reading throughput data critically means checking who published a number and how it was derived before treating it as fact.
How to Read the Throughput Chart
The live throughput chart on the dashboard plots daily flow as a percentage of the pre-war baseline (~110 vessels and ~20 million barrels per day, measured before the February 2026 closure). This normalizes across data sources so a single trend line is comparable day to day, even when the underlying methodology shifts.
60%+ of baseline
Near-normal flow. Strait functionally open to commercial traffic.
30–60% of baseline
Significant disruption. Some operators diverting or delaying transits.
Under 30% of baseline
Effective blockade. Only escorted, flagged, or essential cargoes moving.
Figures marked with a ⚠ on the live chart indicate contested data points — typically a government claim that independent trackers have not corroborated.
Sources Behind This Dashboard's Data
This site's throughput figures are drawn from UKMTO advisories, Windward Maritime Intelligence, and Kpler satellite tracking for vessel counts, and from Kpler, JPMorgan, and the US Energy Information Administration for barrel-flow estimates. Where sources conflict, the dashboard shows the range rather than picking a single “true” number.