A report by the non-partisan Congressional Budget Office (CBO) has found that the war in Iran has cost the US at least $38bn. The report, released on 15 September 2026, also states that the US stockpile of defensive missiles is so depleted it could take at least five years to rebuild, even with increased production.
Much of the cost is attributed to missile defences, with the CBO noting that fending off Iranian ballistic missiles and drones has consumed a large share of Patriot, Thaad, and Navy interceptors. The CBO estimates that the cost of the conflict would grow by $3bn for every additional month it continues, depending on intensity.
The CBO report also indicates that increased energy costs, largely due to disruptions in oil shipments through the Strait of Hormuz, have raised inflation by half a percentage point compared to previous estimates. Brent crude prices jumped from $64 a barrel before the fighting to a peak of $103.
The Pentagon's inspector general released its first review of the war one day prior to the CBO report, stating that the US spent $22.3bn on munitions alone through 30 June, with total spending at $33.4bn. That review also found the fighting had "resulted in strategic inventory shortfalls and revealed industrial base bottlenecks for munitions resupply".