Iran War Cost Estimate Update: $11.3 Billion at Day 6, $16.5 Billion at Day 12

CSIS applied its existing methodology to estimate the munitions usage implied by the reported war cost six days into the campaign. Table 2 presents the results. The technical note below and the previous CSIS commentaryon the costs of the first 100 hours of the war detail the approach.

U.S. Munitions Stockpile After the First Six Days

Overall, the DOD does not appear to have an inventory problem in sustaining the current conflict because munitions use to date and expected future expenditures will not drive any inventories to zero. These expenditures, however, create risks in other theaters such as Ukraine and the western Pacific, as high-demand munitions are diverted to the current war with Iran. Production in FY 2026 will not fully cover usage to date and will therefore limit the hoped expansion of inventories. Table 3 summarizes this analysis.

Ship-Launched Missiles
Navy destroyers and submarines in the region are striking ground targets with Tomahawk missiles. The destroyers also launch the Standard Missile family of missiles for air defense. Ship-launched missiles introduce a unique constraint because ships need to return to port once missiles are depleted. They cannot be reloaded at sea.

• Tomahawk: Using 319 Tomahawks would nearly empty the missile magazines of the U.S. Navy ships in the region. The authors previously estimated that the Navy had about 3,100 Tomahawks available, including those aboard ships. Estimated expenditures in the first six days of Operation Epic Fury would take the inventory down to about 2,700. In FY 2026, 190 Tomahawks are slated for delivery. Of these, 64 are intended to go to the Army and 16 to the Marine Corps.
• Standard Missiles: SM-3s are used against ballistic missiles. SM-6s are used against cruise missiles and drones, as well as against ballistic missiles in their terminal phase. Budget documents indicate deliveries of 76 SM-3s (45 Block IB, 31 Block IIA) and 125 SM-6s in FY 2026.

Air- and Ground-Launched Missiles
In-theater magazine depth does not pose a concern for air- and ground-launched missiles. Cargo aircraft can resupply bases in theater, while replenishment ships can deliver munitions to aircraft carriers.

• Joint Air-to-Surface Standoff Missiles (JASSMs): Although other exquisite munitions exist in the Air Force inventory, JASSMs are likely the main air-launched, long-range missiles used in this war. There are other expensive Air Force munitions, but these are unlikely to have been used in Epic Fury. JASSM inventories are large (approximately 3,500) because of sizable Air Force purchases in the last decade.
• MGM-140 Army Tactical Missile System (ATACMS) and Precision Strike Missile (PrSM): These are medium-range munitions launched from Army vehicles. ATACMS production ended in 2007, although a life-extension program kept the inventory functional. The current inventory is about 1,000. ATACMS's successor, the PrSM, began production in 2022; 60 have been delivered, with 70 more to be delivered in FY 2026.
• Patriot: These have received the most attention because they are needed in both Ukraine and the western Pacific. CSIS previously calculated the Patriot inventory to be about 2,000-1,600 of which were the most modern PAC-3 MSE, and the others were older versions. The Army anticipates the delivery of 172 Patriot missiles this fiscal year. Demand will continue to be high in the Middle East as the Iranians continue their ballistic missile attacks. Allies and partners, particularly those in the Gulf region, will need their own resupply.
• Terminal High-Altitude Aerial Defense (THAAD): There have been no new deliveries of THAAD interceptors since August 2023. Deliveries are set to resume by April 2027. A previous CSIS analysis estimated 534 interceptors to be in the U.S. inventory prior to the Twelve-Day War in June 2025, during which "more than 150" were reportedly
• Joint Direct Attack Munition (JDAM), AGM-154 Joint Standoff Weapon (JSOW), and Standoff Land Attack Missile-Expanded Response (SLAM-ER): These are short- to medium-range, air-launched ground-attack munitions with large inventories.
• Low-cost Uncrewed Combat Attack System (LUCAS): This is an American clone of the Iranian Shahed drones. LUCAS has a long range and is inexpensive, though numbers are limited because the system entered service in 2025.
  

Equipment and Infrastructure Damage

At the time of the publication of CSIS's 100-hour cost estimate, there were many unconfirmed reports of U.S. losses and damages. Three F-15s and one KC-135 remain the only U.S. equipment losses officially confirmed by U.S. Central Command (CENTCOM). Overhead photographs have since become available, which enable some preliminary assessments of damage to U.S. bases. Details remain highly limited. The cost could be significantly higher depending on what equipment was inside the facilities that were struck. In our estimate, the satellite communication systems ("golf balls") are the primary cost driver. CSIS awaits further information from the DOD. The aggregate cost estimate below includes the reported loss of at least one THAAD AN/TPY-2 radar and 11 Reaper drones.

The War Since the Sixth Day: Estimating Costs at Day 12

The DOD continues to release limited information about ongoing operations, making cost estimation difficult. The various, competing public reports on DOD-estimated war costs provide useful signals but lack the detail needed to develop a high-confidence estimate.

The costs of the war are not evenly distributed. The first several days were much more expensive than the subsequent days. U.S. forces appear to have heavily used high-end ground-attack munitions initially-as laid out in Table 2. CSIS's 100-hour estimate was low, as the intense early use of air defense and exquisite strike munitions and the extent of the infrastructure damage exceeded initial assumptions. The use of high-cost ground attack munitions decreased when the U.S. coalition gained air superiority, which allowed the use of much less expensive munitions.

Secretary of Defense Pete Hegseth and Chairman of the Joint Chiefs of Staff General Dan Caine indicated that U.S. forces had approached a "point of munitions transition" by the fourth day of Operation Epic Fury. Thus, the United States continues to fight with precision-guided munitions but predominantly with less expensive, shorter-range weapons that are more abundant in stockpiles. Hegseth reported that only 1 percent of munitions used by Day 14 were stand-off. CSIS's 100-hour estimate placed the munitions transition point earlier in the campaign than subsequent DOD releases suggest.

To illustrate the magnitude of the change, a single Tomahawk missile costs around $3.5 million, whereas a BLU-110 bomb fitted with the JDAM guidance kit costs less than $100,000. Both accurately deliver 1,000-pound payloads.

The United States and its coalition partners also had to defend against attacks by large numbers of Iranian ballistic missiles and drones. These attacks declined by around 90 percent by Day 5, requiring many fewer interceptions. Nearly all of the casualties and damage to bases appear to have occurred during the first few days when attacks were heaviest. Damage to bases appears to have nearly stopped, with a concomitant decline in casualties. Here, our previous calculation gave coalition partners more credit for shooting down Iranian missiles and drones. DOD estimates reported following publication of the original estimate imply a far greater U.S. burden for air defense.

Keeping the assumptions about the U.S.-allied split in air defense and assuming more than 90 percent of munitions used after Day 5-"point of munitions transition"-to be low-cost weapons, Operation Epic Fury is estimated to have cost $16.5 billion by its twelfth day. This number includes the cost of operations-both budgeted and unbudgeted-and damages. War costs will increase by about half a billion dollars a day, unless one side significantly changes its activities or an outside event alters the war substantially. Figure 1 illustrates the daily cost of this war, showing the huge cost impact of the munitions shift, while Figure 2 illustrates the cumulative sum.