WASHINGTON, United States – The U.S. military’s war with Iran has cost about $38 billion through Aug. 1, according to a new Congressional Budget Office assessment that warns spending could continue rising by billions of dollars each month as the conflict continues.
The CBO estimates that continued combat operations would cost roughly $2 billion to $3 billion a month, depending on the intensity of fighting. Costs could rise further during periods of heavier military operations.
The estimate covers direct Department of Defense costs associated with the conflict. It does not include some expenses already incorporated into the Pentagon’s existing budget or the cost of repairing U.S. military facilities damaged during the fighting.
Munitions account for the largest share
Replacing weapons used during the conflict represents the largest portion of the CBO’s estimate.
The agency puts the replacement cost for expended munitions at about $21.7 billion. Increased military flying hours account for another $10.4 billion, while additional fuel costs are estimated at $2.7 billion. Equipment lost in combat adds about $1.9 billion.
Missile-defense interceptors account for a particularly significant portion of the munitions bill.
The CBO estimates that the United States has used roughly one-half to two-thirds of its combined inventory of certain Patriot, THAAD, SM-3 and SM-6 interceptors since June 2025. The agency said replenishing those stocks could take at least five years even if production rates increase.
That depletion represents a cost beyond the immediate dollars spent during combat because the military has fewer interceptors available while manufacturers work to rebuild inventories.
Monthly costs depend on the intensity of fighting
The CBO’s projected future costs are not a fixed bill.
The agency estimates that periods of relatively limited fighting could cost around $2 billion a month. More intense combat could push monthly costs toward $3 billion or higher.
The distinction matters because the total cost of the conflict will depend on how long combat continues and how frequently U.S. forces conduct major operations.
The CBO said its assessment was based on government databases and publicly available information. The Department of Defense did not respond to the agency’s requests for information, leaving the estimate subject to considerable uncertainty.
War is also affecting inflation
The financial effects extend beyond the Pentagon.
The CBO said disruptions to oil and natural-gas shipments have increased energy prices and added inflationary pressure to the U.S. economy. It estimates that the personal consumption expenditures price index could be 0.5 percentage points higher in early 2027 than the agency projected before the conflict began.
Core inflation, excluding food and energy, is also expected to be higher than previously projected, according to the assessment. Higher inflation can in turn contribute to higher interest rates on Treasury securities.
The economic effects therefore extend beyond the direct cost of military operations, particularly while disruptions to energy shipments continue.
Additional funding is being sought
The administration has requested additional funding to cover war-related expenses and replenish military stocks.
The CBO said the administration’s supplemental request included $67.1 billion for the Defense Department, with about $42.3 billion identified as directly related to the Iran conflict.
The CBO’s $38 billion estimate is close to the $37.5 billion cost figure Defense Secretary Pete Hegseth gave lawmakers in July.
The latest estimate nevertheless provides a more detailed breakdown of where the money is going and highlights the additional costs that could accumulate if combat continues.
For the Pentagon, the challenge is therefore not limited to financing current operations. It also includes replacing expensive weapons, rebuilding depleted inventories and addressing production constraints that could limit how quickly those stocks are restored.
Reporting Credit: Congressional Budget Office — assessment of Department of Defense costs, future combat-operation costs, munitions depletion and economic effects; U.S. Department of Defense — military cost estimates and operational information; U.S. Congress — supplemental funding requests and related budget proceedings.
