U.S. May Be Spending Nearly $900 Million Per Day in Conflict With Iran A U.S.-based think tank estimates Washington spent roughly $3.7 billion in the first four days of its campaign against Iran—equivalent to about $891 million per day. The Center for Strategic and International Studies (CSIS) said in a March 5 analysis that the United States spent approximately $3.7 billion during the first 100 hours of operations against Iran, a period typically considered the most intense phase of an air campaign. Of that total, operational costs were estimated at around $196 million, with a significant portion already accounted for in the fiscal year 2026 defense budget. Ammunition replenishment made up the bulk of spending at roughly $3.1 billion, while equipment losses and infrastructure repairs were estimated at about $350 million—most of which has not yet been budgeted. A U.S. fighter jet takes off from an aircraft carrier (Photo: U.S. Central Command) Air operations accounted for a substantial share of overall costs. CSIS estimates that in the first 100 hours alone, the U.S. military spent about $125 million on aircraft sorties, with at least $30 million per day expected thereafter. Roughly 200 U.S. military aircraft are currently engaged in operations across the Middle East, including F-22 Raptor and F-35 Lightning II stealth fighters, F-15E Strike Eagle heavy strike aircraft, F-16 Fighting Falcon multirole fighters, and A-10 Thunderbolt II ground-attack planes. The U.S. Navy has also deployed significant forces to the region, including two aircraft carriers, 14 destroyers, and three littoral combat ships. Operating the naval fleet cost approximately $64.5 million over the first four days, with daily costs estimated at $15 million thereafter. The U.S. military is believed to have used more than 2,000 weapons in the first 100 hours of strikes against Iran. CSIS estimates an average of 1.3 munitions per target, suggesting total usage could reach up to 2,600 weapons. Replenishing these munitions alone could cost around $1.5 billion. A U.S. warship launches cruise missiles toward Iran (Photo: U.S. Central Command) Missile and drone interception has also proven costly. Tehran is estimated to have launched around 500 missiles and 2,000 unmanned aerial vehicles (UAVs), with interception largely carried out by the Patriot missile system and THAAD systems. Replenishing interceptor stockpiles could cost an additional $1.7 billion, according to CSIS. Confirmed U.S. equipment losses remain relatively limited. The most notable incident involved three F-15E Strike Eagle aircraft reportedly lost to friendly fire over Kuwait. With production of the F-15E halted in favor of the newer F-15EX variant, replacing the lost aircraft could cost approximately $309 million. Some U.S. military facilities in Kuwait and Qatar were also damaged in Iranian strikes, with repair costs estimated at no less than $50 million. CSIS analysts say costs may begin to stabilize after the initial high-intensity phase of the conflict, depending on whether the U.S. shifts to less expensive weapons and on the scale and effectiveness of Iran’s retaliation. However, much of the spending has yet to be incorporated into the current defense budget, meaning the U.S. government will likely need additional funding. CSIS said the Pentagon may seek supplemental appropriations or budget adjustments from Congress to cover the costs. The United States and Israel launched a coordinated air campaign against Iran on Feb. 28, reportedly killing several senior military and political figures, including Supreme Leader Ali Khamenei. The strikes triggered a sharp retaliatory response from Tehran targeting Israeli territory and U.S. bases across the Middle East. A U.S. F-15 Eagle fires during an incident over Kuwait on March 2 (Photo: The Times of Israel, X/AMK Mapping) The conflict shows no signs of easing, with Washington urging Israel to continue the campaign “to the end,” while Tehran has vowed to stop only after delivering what it calls a “decisive blow” to the United States.