CBO states that Trump had already spent about $38 billion in the five months leading up to the war with Iran.

The US Congressional Budget Office (CBO) stated that in the first five months since the Trump administration went to war with Iran, it has brought about $38 billion in direct costs to US taxpayers. According to the CBO, these expenses mainly stem from munitions consumption and equipment replenishment, increased flight missions, other military actions, and fuel costs. The report estimates that for every additional month the war continues, the US will incur at least $2 billion to $3 billion in extra costs, and if the conflict escalates, expenses could further increase. The CBO also mentioned that disruptions to oil and gas shipments through the Strait of Hormuz will push up US inflation levels. It is expected that by early 2027, the inflation indicator closely monitored by the Federal Reserve will be 0.5 percentage points higher than previously forecasted, while core PCE inflation will be 0.3 percentage points higher. In addition, the CBO said the war has depleted US munitions stockpiles, and some inventory may take over five years to replenish, which could weaken the US's ability to respond to other major conflicts. The report noted that should a major future conflict requiring a large reserve of missiles and munitions arise, the US defense industry’s production capacity and inventory replenishment speed could face significant pressure.