September 15, 2026 · estimate through August 1
CBO estimates $38 billion in Defense Department costs
CBO estimates about $38 billion in Defense Department costs through August 1, with substantial uncertainty and exclusions from a full war-cost measure.
Before the action
Military operations had continued alongside ceasefire efforts and renewed fighting. The oversight record also describes ammunition shortages and production constraints, making the burden on U.S. resources relevant to evaluating security effects and any claimed net benefit from the campaign. I6
What the U.S. did
CBO publishes an estimate of Defense Department costs for combat operations against Iran through August 1. The report estimates approximately $38 billion, explains substantial uncertainty because the department did not provide information, and describes the scope and limitations of its calculation. I8
What the record establishes
The report provides an official estimate for a defined department and cutoff date, rather than an audited expenditure total. It also discusses interceptor inventory depletion and higher energy prices, identifying burdens that matter alongside military effects when considering the operation’s broader consequences. I8
Costs, durability & open questions
The estimate excludes other departments’ costs and does not encompass a full measure of the war’s total cost, including ordinary peacetime operating costs. Its categories cannot simply be added together, and the August 1 cutoff does not cover subsequent September military activity. I8I7
Read the official evidence 3 sources
Official oversight report · Printed pages 4–8 and 16–18, and Table 4. April–June reporting period with later developments; casualty periods and operational coverage require care.
Presidential congressional notification · Notification describing September 1 strikes and the President’s stated rationale.
Official cost estimate · Summary, estimate through August 1, uncertainty, scope exclusions and warnings against adding overlapping categories.