RismadarVoice Reporters
September 15, 2026
The United States has spent about $38 billion on its war with Iran through August 1 and could incur an additional $2 billion to $3 billion every month for as long as the conflict continues, according to a new assessment by the nonpartisan Congressional Budget Office.
The CBO said the monthly cost could increase substantially if the conflict escalates into repeated exchanges of strikes similar to those witnessed in July. The assessment also warned that the war has placed significant pressure on US weapons stockpiles, particularly missile-defence interceptors.
The estimated $38 billion in direct costs covers the period from February 28 to August 1. It does not include the cost of repairing US military bases and other facilities damaged during Iranian attacks.
The largest component of the expenditure is the replacement of munitions used during combat operations. The CBO estimated that replacing weapons expended through August 1 would cost approximately $21.7 billion.
Of that amount, about $13.1 billion would be required to replace missile-defence interceptors, while another $7.3 billion would go towards replacing land-attack cruise missiles. The remaining $1.2 billion represents other munitions.
The heavy use of interceptors has raised concerns about the readiness of the US military for another major conflict. The CBO said the United States has probably used between half and two-thirds of its inventory of certain interceptors since June 2025, leaving reduced stockpiles for several years.
The agency warned that the depletion could become particularly significant if the United States became involved in another conflict against an adversary possessing large numbers of ballistic and cruise missiles. It specifically cited China and the possibility of a conflict over Taiwan.
The CBO also estimated that replacing lost military equipment would cost approximately $1.9 billion. The figure could rise to about $3.3 billion if the Pentagon chooses to replace destroyed aircraft with newer models.
Among the equipment lost was a THAAD air-defence radar, which the CBO said could cost roughly $500 million to replace and is an important component of the missile-defence system.
The assessment was released a day after a Pentagon inspector-general report warned that the use of munitions during the conflict had created strategic inventory shortfalls and exposed bottlenecks in the US defence industrial base that could slow the replenishment of weapons.
The CBO said a relatively low-intensity continuation of the war would cost between $2 billion and $3 billion per month. It added that the figure could rise if fighting intensified, noting that the conflict cost approximately $3 billion in July alone.
The White House and Pentagon have rejected concerns that US weapons stocks have been dangerously depleted. President Donald Trump has maintained that the United States has extensive ammunition reserves, while Admiral Brad Cooper, the commander of US forces in the Middle East, has said American forces remain adequately armed and prepared for contingencies.
The CBO noted that the Department of Defence did not respond to requests for information used in preparing the analysis, meaning some of the agency’s estimates remain subject to uncertainty.
The financial burden of the conflict comes as the Trump administration seeks additional funding from Congress. In June, the administration requested an $87.6 billion supplemental appropriation, including about $67 billion for the Department of Defence for needs associated with the Iran war.
Republicans have also sought to provide up to $73 billion in additional funding for defence and intelligence through the budget reconciliation process, although the House-approved framework has faced delays in the Senate.
Beyond the immediate military expenditure, the CBO said the conflict could also have economic consequences. Higher energy prices linked to disruptions around the Strait of Hormuz and the Red Sea are expected to contribute to inflation, with the agency estimating that inflation in the first quarter of 2027 could be about 0.5 percentage points higher than it would have been without the war.
The latest assessment therefore places the direct financial cost of the conflict at tens of billions of dollars while highlighting a longer-term challenge for Washington: replenishing weapons inventories and restoring military capacity even if the intensity of fighting declines.
