The nonpartisan Congressional Budget Office estimated Tuesday that U.S. combat operations against Iran have cost the Defense Department about $38.1 billion through Aug. 1, 2026, and would run roughly $2 billion to $3 billion more each additional month if fighting continues, according to Breaking Defense, CNBC, and CBS News. The analysis was requested by Rep. Brendan Boyle (D-Pa.), ranking member of the House Budget Committee. CBO’s public page for the report is publication 62756.

More than half of the bill is munitions replacement: $21.7 billion to refill expended stocks — $13.1 billion for interceptors, $7.3 billion for land-attack cruise missiles, and $1.2 billion for other munitions, Breaking Defense and CBS reported. Beyond that, CBO tallied $10.4 billion in increased flying hours, $2.7 billion in higher fuel costs, about $1.9 billion in equipment lost in battle, and $1.5 billion in other operational costs.

CNBC calculated the war has averaged about $246 million per day across its first five months after President Donald Trump launched it on Feb. 28, 2026. Neither CBO nor Monday’s Pentagon inspector general accounting includes the cost of repairing damaged bases. The IG put war costs at $33.4 billion through late June; adding roughly two months at ~$3 billion each lines up approximately with CBO’s $38 billion figure, Breaking Defense noted.

Interceptor stockpile and China risk

CBO warned the United States has “probably used between one-half and two-thirds of its inventory of certain interceptors since June 2025,” spanning Operation Epic Fury and Operation Midnight Hammer, and that “rebuilding those inventories would probably take at least five years” even with faster production — leaving a “reduced inventory of interceptors for several years.” That shortfall would become “especially problematic” against an opponent with large ballistic and cruise missile forces, namely China in a Taiwan-style scenario, the report said via Breaking Defense, CNBC, and CBS. Systems named in coverage include Tomahawks, JASSMs, THAAD, Patriot, and Standard Missile-3 and -6.

Inflation spillover

CBO also projected the war will raise year-over-year personal consumption expenditures (PCE) inflation by about 0.5 percentage points by early 2027, with core PCE about 0.3 points higher as energy costs ripple through supply chains; gasoline and other fuels would account for roughly 40% of the war’s consumer-price effect by then, CNBC reported. The Trump administration’s earlier $87.6 billion supplemental request (about $67.1 billion defense) is “not directly comparable” with CBO’s estimate because it folds in other priorities and agencies, CBO said via Breaking Defense.

Taxpayers are writing the check; industrial-base bottlenecks and a multi-year interceptor hole are the bill’s quiet sequel — and neither the White House nor DoD answered CBO’s data requests, the outlets reported.

Sources