The six-month-old US war against Iran has cost $38 billion so far and is expected to add another $3 billion a month, according to a report by the Congressional Budget Office (CBO) released Tuesday.
The nonpartisan congressional budget office said the estimate covered costs through August 1. It also projected that the conflict could increase US inflation by 0.5% during the first three months of 2027.
The growing financial burden comes as the Trump administration seeks ways to end the conflict and reopen the Strait of Hormuz, a crucial global energy route.
War puts pressure on US weapons stockpiles
According to the CBO, most of the military costs have resulted from the rapid use of US munitions. The agency estimated that replenishing depleted weapons stockpiles could take as long as five years.
Reuters reported in August that the United States had used “virtually all” of its long-range precision missiles during the conflict.
The shortage of critical munitions, including missile interceptors, could affect the Pentagon’s ability to respond to another major conflict, the CBO said. It cited a potential future confrontation involving China and Taiwan as one scenario in which depleted stockpiles could create challenges.
Defence Secretary Pete Hegseth had sought nearly $90 billion in emergency funding to replenish US munitions supplies during a Senate hearing on July 21.
“Without these funds, we face critical shortfalls,” Hegseth said.
The $38 billion estimate is close to the $37.5 billion in costs Hegseth reported during the July hearing.
CBO says costs could be higher
The budget office noted that its estimate did not include expenses related to recent US strikes on commercial vessels in the Strait of Hormuz or attacks on US military installations in the region.
It also excluded borrowing costs associated with financing the war. Those expenses could add tens of billions of dollars to the overall cost of the conflict.
The Department of Defence did not cooperate with congressional financial auditors during the inquiry, according to the CBO. The White House and Defence Department did not immediately respond to requests for comment.
US-Iran War Costs Reach $37.5 Billion, Pentagon Tells Congress
The report was requested by Brendan Boyle, the top Democrat on the House Budget Committee.
“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 said.
Eighteen US military service members have died in the conflict, according to the report.
Energy prices add to economic pressure
The conflict has also pushed up energy prices following attacks affecting the Strait of Hormuz and energy facilities in neighbouring Gulf countries.
Before the war, roughly 20% of the world’s oil passed through the narrow waterway, making disruptions there a major concern for global energy markets.
The higher war costs are also adding pressure to US public finances. The country’s total public debt surpassed $40 trillion in August.
Trump has repeatedly contrasted the Iran conflict with the US wars in Iraq and Afghanistan that followed the September 11, 2001 attacks.
The US war in Iraq cost about $2 trillion, according to Reuters, while Brown University’s Costs of War project estimates that the two-decade conflict in Afghanistan cost about $2.3 trillion.
