with expenses continuing to rise by approximately $3 billion per month, the Congressional Budget Office (CBO) reported on Tuesday. The Trump administration continues to seek ways to end the war and resume shipping through the Strait of Hormuz.

The nonpartisan budget agency estimates that the war will add 0.5% to inflation in the first quarter of 2027.

Military spending has depleted U.S. ammunition stockpiles and driven up energy prices, raising concerns about the country's ability to respond to other potential conflicts. Furthermore, the costs place an additional burden on an already strained federal budget.

Defense Secretary Pete Hegset cited similar figures during a Senate hearing on July 21, putting the cost at $37.5 billion.

According to the budget office, the bulk of the spending is linked to the heavy use of munitions. The agency estimates that replenishing stockpiles could take up to five years. An August report indicated that the U.S. had exhausted virtually its entire arsenal of long-range precision-guided missiles.

The Department of Defense did not cooperate with congressional financial auditors, the CBO report stated. The White House and the Department of Defense did not respond to requests for comment.

The inquiry was initiated by Representative Brendan Boyle (D-PA), the ranking Democrat on the House Budget Committee.

"Donald Trump’s disastrous war in Iran has already claimed the lives of brave American service members, and others have been wounded," Boyle said. "Beyond this human toll, a nonpartisan CBO report clearly shows that the war has cost American taxpayers tens of billions of dollars, and the meter keeps running."

Eighteen U.S. service members died during the war with Iran.

The report does not account for costs associated with recent strikes on commercial vessels in the Strait of Hormuz and attacks on U.S. military facilities in the region. Also excluded are debt-servicing costs incurred to finance the war, which could amount to tens of billions of dollars more.

A shortage of munitions, including interceptor missiles, could limit the Pentagon's capabilities in the event of another major conflict—such as a potential clash involving China and Taiwan—the CBO warns.

During Senate hearings in July, Hegset requested nearly $90 billion in emergency funding to replenish munitions stockpiles. "Without these funds, we face a critical resource shortage," he stated.

Attacks in the Strait of Hormuz and strikes on the energy infrastructure of neighboring Persian Gulf states have caused energy prices to spike. Before the war began, about 20% of the world's oil supply passed through the strait.