Iran war has cost on average $246 million per day in its first five months, CBO finds

The US war against Iran has cost the Department of Defense over $38 billion through August, with monthly expenses potentially reaching an additional $2-$3 billion depending on the intensity of fighting, according to the nonpartisan Congressional Budget Office (CBO) on September 15. The conflict's broader economic impact is being felt through higher inflation, primarily due to disruptions to oil and natural gas shipments, with Iran's retaliation including the blocking of the Strait of Hormuz.

Inflation projections for the first quarter of 2027 are expected to be about 0.5 percentage points higher than previously forecast, potentially leading to increased interest rates on US Treasury securities. The CBO's estimate, which does not include costs related to military personnel killed or injured, or longer-term veterans' healthcare and disability compensation, was prepared following a request from Rep. Brendan Boyle and other Democratic lawmakers.

The analysis, which aligns with a previous assessment by Defense Secretary Pete Hegseth, highlights concerns about US military stockpiles, with a Pentagon inspector general report noting "strategic inventory shortfalls" due to the war.