In the first 16 days of the Iran war, more than 11 000 munitions were expended by the United States (US) and its allies, according to open-source estimates. These included precision-guided missiles, air defence interceptors, and long-range strike bombs. The cost has reached tens of billions of dollars in a short period.

The estimate is drawn from an analysis by the Payne Institute for Public Policy, a think tank based in Colorado in the US, which compiles publicly available data on missile launches, intercepts, and strike activity from official statements, satellite observations, and verified reporting. While approximate, such estimates are widely used to measure the intensity of modern conflict.

Advanced interceptors are being used by the US and its allies to destroy lower-cost drones and missiles launched by Iran. In practical terms, this means spending several million dollars to stop an attack that may have cost only tens of thousands of dollars to launch (the interceptors used by the US and its allies are vastly more expensive to produce than the drones used by Iran). When repeated hundreds of times, the cost difference becomes substantial.

Estimates of pre-war stockpiles suggest that the pace of munitions consumption is already placing measurable strain on US and its allies’ missile inventories.

Stockpiles of some of the most advanced long-range missile defence systems, designed to intercept ballistic threats before they reach their targets, are estimated to have declined by over 80% since the start of the war.

Other high-altitude missile defence systems, used to destroy incoming threats during their final approach, have seen reductions in the range of 40% to 60%.

More widely deployed air defence systems, used to protect cities and critical infrastructure from aircraft and missiles, are estimated to be down by over 30%.

At the same time, long-range precision strike weapons, used by the US and its allies to hit heavily defended targets from a distance, have declined by approximately 26%.

In Ukraine, this imbalance forced adaptation. Ukrainian forces could not afford to rely exclusively on advanced air defence systems against large volumes of low-cost drones and missiles launched by Russia. Instead, they developed a layered response using cheaper systems, including anti-aircraft guns, portable missiles, and electronic jamming. These are less sophisticated, but more sustainable at scale. 

The US and its allies have largely continued to rely on advanced interceptors to address similar threats. These systems are effective, but expensive and limited in number. 

The Iran war shows that the rate of munitions consumption now exceeds the rate at which many of these systems can be replaced. Modern precision weapons require complex manufacturing processes, specialised materials, and advanced components. Production timelines are measured in years. 

This has direct strategic implications. The US is not at immediate risk of running out of weapons. However, sustained operations at this pace reduce flexibility. A prolonged conflict in one theatre can begin to affect readiness in others.

A good way to think about this is that, due to the long time it takes to replenish stocks of advanced weapons and the rate at which they are being used in the high-intensity bombing campaign in the Middle East, should a similarly intense conflict breakout in another theatre, say the Pacific for example, then there exists the possibility that American defence production rates are unable to meet the demands of multiple theatres.

The Iran war highlights a simple constraint. Advanced munitions are effective, but they are expensive, limited, and slow to produce.

As has ever been the case in modern industrialised warfare, the production line in war is as important as the front line.