Looking Ahead
Total expenditures are large enough for the administration to ask Congress for additional funds. The internal trade-offs to cover war costs within the existing budget would be very difficult. In theory, Congress could redirect some of the $153 billion from the reconciliation bill toward Operation Epic Fury, but that would undermine the concept behind the increase: to build capability, not pay existing bills.
These estimates will not be the final word on war costs. The war, of course, continues, and surprises will occur. Further, these estimates do not include provisions for resupplying Israel, higher fuel costs across the DOD, or increased domestic security—all of which are likely to be included in a final government-wide tally. In addition, there will be future veterans’ benefits for injured service members, though these are not customarily recognized in current budgets.
Technical Note on the Calculations
This technical note provides additional details on the CSIS calculations. The starting point was the DOD’s officially released data. These provided the number of targets struck, the number of Iranian missile and drone attacks, and information to build the U.S. order of battle. News reports, known U.S. capacity, and past campaigns helped fill the gaps.
For Strike Munitions: Interpolating from CENTCOM updates, U.S. forces struck over 2,500 targets by the sixth day of the war. The calculations assumed 1.3 munitions per target based on past U.S. bombing campaigns fought entirely with precision munitions. This means that even for precision munitions, the ratio is not quite one target to one munition. It further assumes that 70 to 80 percent of munitions expended in the first three days of the campaign are exquisite and “mid-tier” ones to strike targets at standoff range.For Air Defense Munitions: Estimates began with Admiral Cooper’s March 3 update, which reported more than 2,000 drone and 500 ballistic missile launches in less than 100 hours of the war. Cooper’s March 5 briefing and General Caine’s March 10 briefing indicated that launches had declined sharply—by 83 percent for drone launches and 90 percent for ballistic missiles. These declines were driven by coalition attacks on launchers and inventories. More frequent updates from the Gulf states gave a sense of the trends of Iranian launch capacity in interpolating between the U.S. updates. The calculation assumed that the United States was responsible for shooting down half of incoming drones and ballistic missiles. A “shoot-look-shoot” shot doctrine was assumed for most U.S. air defenders. Coalition partners, by intercepting the remaining drones and ballistic missiles, greatly decreased U.S. costs.For Cost of Replacing Munitions: FY 2026 budget documents provided the weapons costs. Munition costs assume a like-for-like replacement with items in production (e.g., SM-3 Block IIA for Block IB expended).For the Cost of Operations and Support: Operating costs are based on Congressional Budget Office estimates, with an addition above the base amount to account for costs of a higher operational tempo.
CSIS continues to refine its methodology to account for additional information as it becomes available.
Mark F. Cancian (Colonel, U.S. Marine Corps Reserve, ret.) is a senior adviser with the Defense and Security Department at the Center for Strategic and International Studies (CSIS) in Washington, D.C. Chris H. Park is a research associate for the Arleigh A. Burke Chair in Strategy at CSIS.
The authors are grateful for the expeditious work by Madison Bruno and Julia Huh in editing and formatting this article.
If you are interested in learning more about this topic, explore CSIS’s Executive Education courses Meeting China’s Military Challenge and Inside DOD’s FY 2027 Budget.