The United States has spent about $38 billion (52 trillion won) in the roughly five months since war with Iran broke out, according to a new analysis. With total U.S. national debt topping $40 trillion and fiscal pressure mounting, war costs are projected to add more than $3 billion (4.1 trillion won) a month if military tensions escalate further.
The Congressional Budget Office estimated additional Defense Department costs stemming from the armed conflict with Iran at about $38 billion as of Aug. 1, according to Reuters and other outlets on the 15th. That is close to the $37.5 billion figure disclosed in July by U.S. Defense Secretary Pete Hegseth.
More than half of the war costs came from expended weapons and munitions. The CBO said replacing spent munitions cost $21.7 billion, or 57% of total outlays. Costs tied to increased aircraft flight hours followed at $10.4 billion, while higher fuel costs and replacement of equipment lost in combat accounted for $2.7 billion and $1.9 billion, respectively.
The CBO said the burden on the Defense Department will grow the longer the fighting continues. If the intensity of combat stays at the low levels seen in May and June, monthly costs would rise by about $2 billion, but escalation to July levels would push the monthly figure to $3 billion, the office estimated. A wider conflict could drive monthly spending above $3 billion.
The war is also expected to weigh significantly on U.S. military readiness. Analysts note the risk that a sharp drop in stockpiles of key weapons such as interceptor missiles could weaken the U.S. military's ability to respond in a contingency, including a conflict over China and Taiwan. The Defense Department does not disclose how many interceptor missiles it holds, but based on related spending records and purchase histories, the U.S. is estimated to have used between half and as much as two-thirds of its interceptor missile stockpile since June 2025. The CBO said restoring depleted weapons inventories to previous levels alone could take at least five years.
Significant spillover effects are also expected for the broader U.S. economy. The CBO estimated that personal consumption expenditures (PCE) inflation in the first quarter of next year will run 0.5 percentage points higher than its February projection. Core PCE inflation, which excludes food and energy, is expected to be 0.3 percentage points higher than previously forecast.
Representative Brendan Boyle of Pennsylvania, the ranking Democrat on the House Budget Committee who requested the report, said the catastrophic war with Iran has already cost American taxpayers tens of billions of dollars on top of the loss of life.
