The series counts crude and product tankers passing through the Strait of Hormuz each day, positioned from satellite AIS signals published by IMF PortWatch. Raw daily counts swing too much to read, so the chart plots the trailing 7-day mean. This page reads the tanker count, not the all-vessel total, because container traffic returning to the strait says nothing about crude.
At its narrowest the strait is 21 miles wide, with shipping lanes two miles across. Saudi Arabia, Iraq, Kuwait, the UAE and Qatar have no other sea route out of the Gulf. Until its first closure in March 2026 the strait carried about 20% of global petroleum liquids consumption, roughly 21 million barrels a day.
The baseline is the strait's own pre-disruption traffic, so the reading answers one question: how much of normal still gets through. A strait running at half its baseline is a supply shock in progress. A fall against the baseline deepens the shock. A rise back toward baseline is the real all-clear.
Every barrel that stops moving through Hormuz shows up in the Brent price, then in the CPI, then in interest rates and stock valuations. The transit count moves before the price does.