The U.S. military has incurred about $38 billion in costs from combat operations against Iran through Aug. 1, and the conflict has consumed between one-half and two-thirds of the U.S. inventory of certain missile-defense interceptors since June 2025, according to a Congressional Budget Office analysis released Sept. 15.
The estimate includes Patriot, Terminal High Altitude Area Defense (THAAD), Standard Missile-3 and Standard Missile-6 interceptors. CBO said the Pentagon does not disclose how many interceptors it has in inventory; analysts compared reported expenditures with the total number of missiles the Defense Department has purchased to estimate usage. The estimate applies to the combined inventory of those four systems.
Rebuilding those stocks could take at least five years, even if production rates increase, the agency found. The interceptors accounted for $13.1 billion of the $21.7 billion CBO estimates the Pentagon would need to replace in munitions expended through Aug. 1. Land-attack cruise missiles accounted for another $7.3 billion, with $1.2 billion for other munitions.
CBO estimates unit costs of roughly $4 million for a Patriot or SM-6, $12 million for a THAAD interceptor and $28 million for a sophisticated SM-3. The agency said the United States has already used significant quantities of these weapons defending Israel and then expended more during Operation Epic Fury.
The $38 billion figure includes expended munitions, equipment losses, increased flying hours, other operations and higher fuel costs. It does not include costs borne by other federal agencies or military operating costs already included in the federal budget. The highest costs beyond munitions were $10.4 billion for increased flying hours, $2.7 billion for fuel and $1.9 billion to replace equipment lost in battle, including a THAAD radar destroyed by Iran.
A separate Defense Department inspector general report estimated the cost of the operation at $33.4 billion through June 29. The administration had requested $87.6 billion in supplemental funding in June, including $67.1 billion for the DoD, with $42.3 billion identified as directly related to the conflict—about 10% higher than CBO’s estimate.
CBO said the Pentagon did not respond to its requests for information, so analysts relied on government databases and public reports, and the estimate is subject to considerable uncertainty. The initial phase of Operation Epic Fury involved about 250 tactical aircraft, including roughly 90 from two carrier strike groups, as well as an amphibious ready group.
CBO estimates each additional month of fighting would cost roughly $2 billion to $3 billion if the intensity remains relatively low, with costs potentially higher if operations intensify. The depleted interceptor stocks could pose a particular problem in a conflict with China, CBO said, because Beijing maintains large numbers of ballistic and cruise missiles.
Sources: Defense News · Army Times