War on Iran cost U.S. more than $38B: Congressional Budget Office

The U.S. war against Iran has cost the Department of Defence more than $38 billion through August 1, and will continue costing up to $3 billion a month or more depending on the intensity of the conflict, according to an assessment released on Tuesday (September 15, 2026) by the nonpartisan Congressional Budget Office.

CBO said the war is expected to contribute to inflation into the first quarter of 2027, making inflation roughly 0.5 percentage points higher than they had previously estimated. That's driven largely by the reduction of oil and natural gas shipments through the Strait of Hormuz and disruptions to shipping through the Red Sea.