The US military campaign against Iran has cost the Pentagon approximately $38 billion through July 2026 and could consume an additional $2 billion to $3 billion each month, according to a new assessment by the Congressional Budget Office (CBO). The nonpartisan agency's report, released on 16 September 2026, also warned of severe depletion of missile-defence stocks and measurable inflationary pressure on the broader American economy.

Operation Epic Fury: What the $38 Billion Covers

The CBO examined operational, logistical, and economic costs linked to Operation Epic Fury, which began on 28 February. The campaign's initial phase ended when a ceasefire took effect on 8 April, but President Donald Trump declared the ceasefire over on 10 July following attacks on tankers transiting the Strait of Hormuz.

The $38 billion estimate breaks down as follows: $21.7 billion to replace missiles and munitions — the single largest expense — followed by $10.4 billion in additional flying hours, $2.7 billion in higher military fuel costs, $1.9 billion for equipment lost in combat, and $1.5 billion in other operational expenses. Within the munitions bill, $13.1 billion went toward missile-defence interceptors and $7.3 billion toward land-attack cruise missiles.

Notably, the estimate excludes the cost of repairing US military facilities damaged by Iranian strikes, diplomatic and foreign assistance outlays, and long-term medical care and disability compensation for injured service members and veterans — meaning the true fiscal footprint of the conflict is almost certainly larger.

Missile-Defence Stockpiles at Critical Levels

The CBO's most alarming finding concerns America's missile-defence inventory. The report estimated that the United States has probably used between one-half and two-thirds of its missile-defence interceptor stocks since June 2025. Rebuilding those reserves could take at least five years, even if the Pentagon accelerates procurement schedules.

'The shortfall would become especially problematic if a conflict arose with an opponent whose arsenal included large numbers of ballistic and cruise missiles,' the CBO said in its report. The agency specifically identified China as possessing an arsenal that could play a major role in any future military conflict involving Taiwan — a pointed reference to the strategic implications of the stockpile drawdown.

The CBO also noted that the Pentagon did not provide the data it formally requested, leaving the agency to rely on government databases and publicly available records. Its findings are therefore subject to, in its own words, 'considerable uncertainty.'

Economic Fallout: Inflation and Energy Costs

Beyond battlefield accounting, the conflict has disrupted oil and natural gas flows through the Strait of Hormuz and shipping through the Red Sea. The CBO calculated that the resulting energy cost surge added 2.3 percentage points to the annualised US inflation rate during the second quarter of 2026.

Looking ahead, the agency projected that inflation in the first quarter of 2027 will be 0.5 percentage points higher than it had forecast before the war began. Elevated inflation, in turn, is expected to push up interest rates on US Treasury securities, compounding the fiscal burden.

Congress and the White House: Funding Requests

Defence Secretary Pete Hegseth told Congress in July that operations against Iran would cost approximately $37.5 billion through September — a figure broadly consistent with the CBO's independent assessment. The White House has since requested $87.6 billion in supplemental funding, of which $67.1 billion is earmarked for the Pentagon. The CBO assessed that roughly $42.3 billion of the Pentagon request appears directly related to the conflict.

The gap between the White House's Pentagon request and the CBO's conflict-specific estimate suggests significant additional spending on items not directly tied to combat operations, a distinction likely to draw scrutiny on Capitol Hill.

What Comes Next

With monthly burn rates of $2 billion to $3 billion and a five-year timeline to replenish critical interceptor stocks, the Iran campaign's fiscal and strategic consequences will extend well beyond the conflict itself. Congressional appropriators face pressure to approve supplemental funding while simultaneously grappling with the long-term readiness implications of a depleted missile-defence arsenal.