US spends $3.7 billion on war with Iran in initial 100 hours

March 6, 2026 • Al Jazeera

US spends $3.7 billion on war with Iran in initial 100 hours

Pentagon Estimates $3.7 Billion in Costs for US-Iran War Effort

The Pentagon has estimated that the ongoing war with Iran has cost the United States approximately $3.7 billion in its first 100 hours, or nearly $900 million per day. According to a new analysis by the Center for Strategic and International Studies (CSIS), most of these costs were not budgeted for, leaving the Pentagon with an estimated $3.5 billion in unbudgeted expenses.

Researchers Mark Cancian and Chris Park noted that only a small portion of the total cost was already allocated in the budget, while the majority of the expenses were not accounted for. This means that the Pentagon will likely need to request additional funding soon to cover these costs, which could pose a challenge for the Trump administration.

The analysis drew on Congressional Budget Office (CBO) estimates and adjusted for inflation and unit size. It estimated that over 2,000 munitions of various types were expended in the first 100 hours of the war, with an additional $758 million per day needed to replenish the inventory.

United States Defense Secretary Pete Hegseth has stated that the US bombardment on Iran is expected to increase in intensity, with more fighter squadrons and defensive capabilities being deployed. The report’s authors noted that while air campaigns typically slow down after the initial period of a conflict, the unbudgeted costs here will be substantial.

The Trump administration may decide to request a supplemental appropriation to cover the war expenses, as was done by the George W Bush administration during previous conflicts in Iraq and Afghanistan. However, this move is likely to become a focal point for opposition to the war.

The human cost of the conflict has been significant, with over 1,332 people killed in Iran since the US and Israeli bombardment began, according to the Iranian Red Crescent. The death toll in Lebanon has also risen to at least 123 people, while there have been nine deaths in Gulf Arab countries.

Source: Al Jazeera