Secretary of Defense Pete Hegseth testifies during a Senate Appropriations Committee hearing in the Dirksen Senate Office Building on Capitol Hill on July 21, 2026 in Washington, D.C. (Photo by Finn Gomez/Getty Images)
WASHINGTON — The cost of U.S. military operations in Iran has exceeded $40 billion and the war will continue to cost taxpayers between $2 billion and $3 billion per month, according to an analysis released Tuesday by the nonpartisan Congressional Budget Office.
The ongoing bombing campaign, which President Donald Trump launched alongside the Israeli government in February, has also significantly reduced American military weapons stockpiles, according to the analysis.
CBO Director Phillip L. Swagel wrote in a letter accompanying the report that “the main opportunity cost of the conflict thus far has been the large expenditure of missile defense interceptors, which will leave the United States with a reduced inventory of interceptors for several years.
“The shortfall would become especially problematic if a conflict arose with an opponent whose arsenal included large numbers of ballistic and cruise missiles.”
Swagel noted in the letter that because the Defense Department “did not respond to CBO’s requests for information” the report “relied on government databases and public reports.”
“As a result, CBO’s estimates are subject to considerable uncertainty,” he wrote.
In addition to the direct costs, CBO expects the war to increase inflation in the first quarter of 2027 by 0.5 percentage points due to the rise in energy prices, predominantly caused by increased danger and difficulty navigating the Strait of Hormuz.
“CBO’s analysis does not assign financial costs to U.S. military personnel killed or injured in the conflict, nor does it include longer-term costs associated with future increases in outlays for veterans’ health care and disability compensation,” Swagel wrote. “It also does not include costs that could emerge in the future if ships, aircraft, and other equipment need repairs or additional maintenance as a result of their use in the conflict.”
Boyle request for numbers
The analysis stems from a request House Budget Committee ranking member Brendan Boyle submitted to CBO in March.
The Pennsylvania Democrat wrote in a statement released Tuesday that the “disastrous war in Iran has already taken the lives of brave American servicemembers and left others wounded.”
“Beyond that human toll, this nonpartisan CBO report makes clear that the war has also cost American taxpayers tens of billions of dollars and counting, while continuing to drive up costs,” Boyle added. “Donald Trump and Republicans have spent years telling Americans that we cannot afford to help families here at home, but apparently they can find tens of billions of dollars, and potentially much more, for a reckless war that is leaving Americans to pay the price.”
Inspectors general report
The CBO report differs somewhat from a report released earlier this week by inspectors general from the departments of Defense and State as well as the U.S. Agency for International Development.
That report estimated the war cost at $33.4 billion through June 29, though it didn’t include any costs since then.
Neither report includes the cost of damaged military infrastructure, with Swagel writing it was “unable to estimate the cost of damage to U.S. bases and facilities in the Middle East for two reasons.
“First, DoD has not provided CBO with information about the value of damaged or destroyed equipment and property. Second, the extent of repairs or rebuilding that DoD plans to undertake is unclear. And even if the bases were fully repaired or rebuilt, a portion of the costs of doing so could be paid by host nations.”
The inspectors general wrote their report “did not include the cost of military construction for damaged infrastructure in its estimate because the DoW has not determined what its future posture will be in the region, how it will construct its bases, and what percentage of the construction costs Allies and partners will contribute.”
Administration pleads for more war funding
Defense Secretary Pete Hegseth testified before the Senate Appropriations Committee in July that without extra money from Congress, the department would “face critical shortfalls that threaten” its ability to “pay our service members, rapidly replenish equipment and munitions, and sustain vital operations without disruption.”
The Trump administration asked Congress in June to provide $87.6 billion in emergency funding for the war as well as other expenses not covered in annual government spending bills.
That supplemental request proposed $67.15 billion for the Defense Department, $3.36 billion for the State Department, $2.03 billion for the U.S. Coast Guard, $40.26 million for the FBI, $36.18 million for the Treasury Department’s office of terrorism and financial intelligence and $13.1 million for the Homeland Security Department’s operations and support account that was part of a “classified request.”
Congress has not yet approved the additional spending and isn’t likely to this month before both chambers return to the campaign trail ahead of November’s midterm elections.
The inspectors general wrote in their report that because lawmakers have not provided dedicated funding for the Iran war that the Defense Department has “used base budget funds that otherwise would be used for standard operational activities, such as planned training and maintenance activities.”