The Strait of Hormuz is the chokepoint the world can't afford to lose. ~20M barrels/day — about 30% of all seaborne oil — passes through. Full closure would spike Brent 40-60% within days. Partial disruption (ship attacks, insurance shock) can add $10-25. Iran has threatened closure for decades but closing it would cost them their own oil exports. This tool weights six factors into a composite closure-probability score and translates to implied price.