CBO Puts the Iran War at $38 Billion and Raises Its Inflation Forecast

The budget office says the conflict has cost the Pentagon about $38 billion so far and will add $2 billion to $3 billion a month, while lifting its inflation projection for early next year.

Assembled by Claude from 10 sources at 10 outlets · Tuesday, September 15, 2026, Evening edition, 5:14 PM EDT · no human byline

What happened

The Congressional Budget Office released an assessment of the Department of Defense's costs for the armed conflict against Iran, together with the conflict's economic and budgetary effects cbo.gov. CBO estimates that as of 1 August, the war had cost the department approximately $38 billion econbrowser.com. That figure reflects the cost of replacing expended munitions and equipment lost in battle, increased flying hours, other operations and higher fuel costs econbrowser.com. The estimates do not include costs related to US military personnel militarynews.com.

The budget office said the prolonged campaign will run at $2 billion to $3 billion a month for as long as it lasts politico.comtime.com. Its analysis was limited because the Defense Department did not respond to CBO's requests for information nytimes.comnewsmax.com. Among the shortfalls CBO identified was a deficit in critical munitions newsmax.com, with the agency separately costing defence interceptors and $1.2 billion for other munitions cbsnews.com.

Why it matters to investors

The report converts a geopolitical event into a macro variable. CBO put headline personal consumption expenditures inflation in the first quarter of 2027 at 0.5 percentage points above its February projection, and revised core PCE as well ts2.techen.bloomingbit.io. That is an official body attributing a measurable share of next year's inflation to the war.

TIME framed the total as approaching $40 billion and said the conflict has fuelled inflation time.com. For anyone modelling the rate path, the significance is that the fiscal cost and the price effect now come from the same source document, rather than from competing private estimates. The monthly run rate is the part that compounds politico.com.

What to watch

The first marker is whether the Pentagon starts answering CBO's questions. The budget office said plainly that the Department of War did not respond to its information requests newsmax.comnytimes.com, which means the published number is a floor built from what CBO could see rather than a full accounting.

The second is munitions replacement. The White House and the Pentagon have downplayed concerns about depleted weapons stocks cbsnews.com, while CBO's own tally rests heavily on replacing what has been expended econbrowser.commilitarynews.com. The third is the inflation revision itself, which is dated to the first quarter of 2027 and therefore lands inside the window the Federal Reserve is currently forecasting over ts2.techen.bloomingbit.io. If the monthly cost holds at the top of CBO's range, both the deficit line and the price line move again time.com.

Sources

1. ts2.tech: CBO Puts the Iran War at $38 Billion, With a $3 Billion Monthly Tail - TS2 Tech (2026-09-15)
2. newsmax.com: CBO : Iran War Cost Hits $38 Billion, Forecast to Rise $3 Billion Monthly | Newsmax.com (2026-09-15)
3. en.bloomingbit.io: CBO Estimates Iran War Cost US $38 Billion in First Five Months - bloomingbit (2026-09-15)
4. politico.com: Iran war has cost taxpayers $38B — and counting - POLITICO (2026-09-15)
5. nytimes.com: Independent Budget Office Estimates Iran War Has Cost $38 Billion - The New York Times (2026-09-15)
6. time.com: Iran War Has Cost U.S. Nearly $40 Billion and Fueled Inflation, CBO Finds - TIME (2026-09-15)
7. cbsnews.com: Iran War could cost $2 billion per month, Congressional Budget Office estimates (2026-09-15)
8. militarynews.com: Iran war has cost the US more than $38B, budget office says - MilitaryNews.com (2026-09-15)
9. econbrowser.com: CBO on Iran War Costs (2026-09-15)
10. cbo.gov: Estimating the Cost of Combat Operations Against Iran (2026-09-15)