As the US restarts war on Iran, is its weapons stockpile running low?

The US has expended a significant number of munitions since the war began in February.

United States President Donald Trump is scheduled to address a defence summit at the US Army War College on Wednesday, where he is expected to laud US investments in its armed forces that he has argued have helped add a new edge to history’s most powerful military.

But his speech comes at a time when the US’s war on Iran has significantly depleted the US military’s weapons stockpile.

The summit, which will be held in Carlisle, Pennsylvania, comes as the US has re-ignited attacks on Iran in the past week, and as Trump has threatened to continue a war that, according to recent US polls, is highly unpopular among Americans facing high costs of living.

The US has expended half of at least four of its most critical munitions since its war on Iran began on February 28, and has racked up billions of dollars in weapons expenses, analysis shows.

Replenishing low stockpiles could take anywhere between several months and several years. Analysts warn that a shrinking arsenal could put the US in a less formidable position in a potential future conflict – particularly against China.

Here’s what we know about the US weapons inventory:

Following an April ceasefire between the US and Iran, and the subsequent signing of a memorandum of understanding in June, the conflict kicked off again after the US Central Command launched heavy waves of attacks on Iran’s military sites last Wednesday, saying it was aiming to degrade Tehran’s military capabilities. Huge, hourlong attacks have continued for four nights since Sunday, including on railway tracks and bridges.

Both sides traded low-intensity attacks throughout the ceasefire period. However, the US escalated air attacks last week after Iran fired on three commercial ships passing through the Strait of Hormuz – because those vessels had used a shipping route not approved by Tehran.

Each blames the other for violating the ceasefire, and at last week’s NATO leaders’ summit, Trump declared the pact with Iran over, although he said American negotiators could continue talks. Washington has also reinstated a naval blockade on Iran-linked ships trying to transit the waterway and has re-imposed sanctions on Iran.

Iran’s Islamic Revolutionary Guard Corps has responded with retaliatory attacks on US military assets in Bahrain, Oman, Qatar and Kuwait.

More than a dozen people have been killed in Iran since the new wave of US attacks, including civilians.

“We’re going to knock out all their power plants. We’re going to knock out all their bridges unless they get to the table and negotiate,” Trump threatened in a Fox News interview that aired on Tuesday.

Attacking civilian infrastructure is a violation of international law.

Washington’s supplies are running low but have not reached a critical level, according to analysis of the US weapons inventory by the Center for Strategic and International Studies (CSIS), a Washington-based think tank.

In the 39 days of conflict between the start of the US-Iran war in February and the ceasefire in April, the US hit more than 13,000 targets, focusing mainly on using seven of its most powerful missiles and air defence systems: Tomahawk missiles, Joint Air-to-Surface Standoff Missiles (JASSM), Precision Strike Missiles (PrSM), Standard Missile-3 (SM-3), Standard Missile-6 (SM-6), Terminal High Altitude Area Defenses (THAAD) and Patriots.

For at least four of the munitions, Washington likely expended more than half of its available stockpiles, although many lower-grade alternatives are still in stock, according to CSIS. Government data on weapons inventory is classified.

Here’s how the munitions were used:

Analysts from CSIS say that while the US may have enough to continue hitting Iran in the near-term war, it has reduced its stockpiles so significantly that it may not have enough for potential future wars, especially against a formidable rival like China.

Replenishing high-capability and costly weapons like the ones the US has used in Iran will likely take several years.

Trump and senior administration officials have publicly maintained that the US has an “unlimited” supply of weapons as the US-Iran war has raged on.

However, in March, Trump said administration officials met with the heads of US manufacturers, including Lockheed Martin, Boeing, Raytheon, BAE Systems, Honeywell Aerospace, L3Harris Missile Solutions, and Northrop Grumman. He said all promised to “quadruple” production and that increased manufacturing was already under way.

Subsequently, in June, Trump signed the Defense Production Act, an executive order compelling US weapons manufacturers to speed up production, citing existing conditions “which may pose a direct threat to the national defense or its preparedness programs”.

An order compelling private actors to ramp up production likely reflects timeline concerns within the Pentagon, analysts note.

In the short term, Washington is also unlikely to meet demands from its allies, and may not have the capacity to supply the THAADs and Patriots that Ukraine says are crucial in its war against Russia.

Already, supply orders have hit road bumps. Japan’s order of 400 Tomahawks from Raytheon was meant to be delivered between 2025 and 2027, but US Defense Secretary Pete Hegseth said in May that two more years could be added to the schedule.

Meanwhile, Switzerland began negotiations with France, Israel and South Korea in June to buy another missile defence system after its 2022 order from Lockheed Martin and Raytheon continued to face delays.

Hegseth said in May that it could take “months and years” to replenish the supplies, based on the weapons system.

Analysts reckon it could take the US between one and four years to get its most exquisite munitions stockpiles back to pre-Iran war levels, even as Trump has boasted that new weapons plants are being built around the US and production is being ramped up.

Trump’s administration is set to buy large amounts of advanced munitions in its proposed $1.5 trillion 2027 defence budget – a 44 percent increase from 2026’s defence budget.

According to CSIS, estimated timelines to replenish the seven critical munitions, based on existing production facilities, are:

Expensive interceptor missiles are facing mounting pressure from Iran’s cheaply produced drones.

The Senate votes 50-46 to block debate on the annual defence bill over war funding and defence cooperation with Israel.

Nine European countries and Ukraine have launched a coalition to build Europe’s own defence against ballistic missiles.

Syria regains voting rights in the OPCW as new leadership makes progress in addressing chemical weapons issues.

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