US Military Campaign Against Iran Incurs $3.7 Billion in First 100 Hours, CSIS Analysis Finds
According to new research from the Washington-based think tank Center for Strategic and International Studies (CSIS), the United States' military campaign against Iran has cost an estimated $3.7 billion in its first 100 hours. The analysis, conducted by researchers Mark Cancian and Chris Park, highlights that the majority of this spending was not previously budgeted, raising concerns about future financial and political implications.
Heavy Spending Driven by Munitions and Advanced Systems
The report estimates that the conflict, now in its seventh day, has cost Washington approximately $891.4 million per day. This high expenditure is largely attributed to the use of over 2,000 munitions and the deployment of advanced military systems, including stealth bombers, during the initial phase. Replenishing these weapons on a like-for-like basis would cost about $3.1 billion, with daily replenishment costs rising by roughly $758.1 million.
The researchers based their calculations on estimates from the Congressional Budget Office (CBO) for operating and support costs of US military units, adjusted for inflation and unit size. They also added an extra 10 percent to account for what they described as a "higher operational tempo," reflecting the intense nature of the campaign.
Majority of Costs Not Budgeted, Prompting Funding Concerns
The CSIS report found that around $3.5 billion of the $3.7 billion spent in the first 100 hours was not previously budgeted. This unbudgeted spending means the Pentagon may soon need to seek additional funds from Congress. The scale of these unexpected costs could create political complications for the administration of US President Donald Trump, as noted in the report.
"That means that the [Department of Defense] will need additional funds at some point because the level of budget cuts needed to fund this conflict internally would likely be politically and operationally difficult," the report stated. It added that any request for additional funding could become "a focal point for opposition to the war."
Pentagon Signals Expansion and Potential $50 Billion Request
US Defense Secretary Pete Hegseth has indicated that the scale of the campaign may increase further, with the US bombardment of Iran "about to surge dramatically," involving more fighter squadrons, defensive capabilities, and bomber pulses. While air campaigns often slow after initial intense operations, the report emphasized that the unbudgeted costs will remain substantial.
The administration may seek a supplemental funding request from Congress, similar to approaches used during the early phases of the wars in Iraq and Afghanistan. According to reports, the Pentagon has prepared a $50 billion supplemental funding request to replenish munitions such as Tomahawk and Patriot missiles, as well as THAAD interceptors used in the first week, and other damaged or worn-out equipment.
Lawmakers are already concerned about the federal budget deficit and rising interest on US government debt, so another $50 billion request might give some legislators pause, as noted in the analysis.
Human Toll and Regional Casualties
Alongside the financial costs, the conflict has caused significant human casualties across the region. The Iranian Red Crescent reported more than 1,332 people killed in Iran since US and Israeli strikes began last Saturday, with UNICEF noting at least 181 children among the dead. In Lebanon, the health ministry said Israeli strikes this week have killed at least 123 people.
- Six US servicemen have lost their lives.
- Eleven people have been killed in Israel.
- Nine people have died in Gulf Arab countries.
This CSIS report underscores the escalating financial and human impacts of the US military campaign against Iran, with ongoing operations likely to drive costs higher and necessitate critical funding decisions in Congress.
