Nice full-page analysis at FT on how the Saudis have worked hard to give themselves a response option if Iran attempts to close Hormuz (far harder than imagined).
The relevant bit:
Earlier this year, Riyadh and Abu Dhabi opened new pipelines that will increase the ability of countries to bypass the strait. Fully operational, 6.5m barrels per day, or about 40 per cent of total flows, will now be able to take alternative routes. “The Middle East is much better prepared now than a year ago to cushion the impact of a disruption in the Strait of Hormuz,” says Edward Morse, head of commodities research at Citigroup and former US deputy assistant secretary of state for international energy policy.
The key number is the Saudi one. The kingdom has managed to siphon off half their exports to other vectors.
Then look at who's at risk. US imports only 42% of its oil, and only 16% of that comes through straits, so only about 7% of US imported oil comes through straits, or roughly 3% of total US oil usage comes through straits. Of total US energy usage, that's just under 1.5%.
So no, the US won't be crippled when Hormuz gets shut down - as unlikely as that feat would be for Iran.