U.S. combat operations against Iran cost about $38 billion through Aug. 1, while the military used between one-half and two-thirds of its combined inventory of four major missile-defense interceptor systems since June 2025, according to a Congressional Budget Office analysis reported by Defense News. The estimate covers Patriot, Terminal High Altitude Area Defense, Standard Missile-3 and Standard Missile-6 interceptors.

The inventory estimate does not rely on a disclosed Pentagon count. The Defense Department does not publicly state how many of those interceptors it holds, so CBO analysts compared reported expenditures with the total number of missiles the department has purchased. The resulting range applies to the four systems as a combined inventory, rather than to each system separately.

CBO estimates that replacing all munitions expended through Aug. 1 would cost $21.7 billion. The four interceptor systems account for $13.1 billion of that amount. Land-attack cruise missiles account for another $7.3 billion, while other munitions account for $1.2 billion.

The interceptor use matters because the weapons are costly and production rates are relatively low. CBO estimates a unit cost of roughly $4 million for a Patriot or SM-6 interceptor, $12 million for a THAAD interceptor and $28 million for a sophisticated SM-3 interceptor. The agency said the United States had already used significant quantities of the weapons defending Israel before expending additional interceptors during Operation Epic Fury.

CBO estimates that rebuilding the depleted stocks could take at least five years, even if production rates increase.

The $38 billion estimate includes expended munitions, equipment losses, increased flying hours, other operations and higher fuel costs. It excludes costs borne by other federal agencies and military operating costs already included in the federal budget. Beyond munitions, the largest reported categories were $10.4 billion for increased flying hours, $2.7 billion for fuel and $1.9 billion to replace equipment lost in battle. The equipment losses included a THAAD radar destroyed by Iran.

CBO said the campaign involved large munitions expenditures during its first few weeks, particularly while U.S. forces defended against Iranian ballistic-missile and drone attacks. The initial phase of Operation Epic Fury involved about 250 tactical aircraft, including roughly 90 aircraft from two carrier strike groups, along with an amphibious ready group. Bombers, airlifters, refueling tankers, other Navy vessels and Army air-defense, aviation and artillery units supported those forces.

A Defense Department inspector general report put the operation’s cost at $33.4 billion through June 29. The different totals cover different dates and come from separate estimates. CBO’s calculation extends through Aug. 1 and includes the categories described in its analysis.

The administration requested $87.6 billion in supplemental funding in June, including $67.1 billion for the Defense Department. Of that request, $42.3 billion was identified as directly related to the conflict, an amount about 10% higher than CBO’s estimate of costs through Aug. 1.

CBO estimates that each additional month of fighting would cost roughly $2 billion to $3 billion if the intensity remained relatively low. Costs could be higher if operations intensified. The agency also identified a potential future concern involving the depleted interceptor stocks, saying they could pose a particular problem in a conflict with China because Beijing maintains large numbers of ballistic and cruise missiles.

CBO cautioned that its estimate is subject to considerable uncertainty because the Pentagon did not respond to the agency’s requests for information. Analysts instead relied on government databases and public reports, making the $38 billion figure and the interceptor-depletion range estimates rather than a disclosed accounting of every operation or missile in the inventory.