‘The math doesn’t work’: Iran’s cheap drones are forcing the US to burn costly missiles faster than expected

Heavy use of Tomahawk missiles and air defence interceptors in the Iran war is raising concerns in Washington over costs, stockpiles and a potential $50 billion Pentagon funding request.

• US has depleted years of critical munitions in Iran conflict
• Pentagon requests $50B more for war, igniting Congress debate
• Tomahawk missile use far exceeds recent US production rates

Did our AI summary help?

The United States has used up 'years' of critical munitions since the start of its war with Iran, according to three people familiar with the matter cited by the Financial Times, raising concerns about the cost of the conflict and the Pentagon’s ability to replenish key weapons stockpiles.

The rapid depletion includes advanced long-range Tomahawk cruise missiles, one of the US military’s most important precision strike weapons, the people said.

“It is a massive expenditure of Tomahawks,” one person familiar with the US military’s use of munitions told the Financial Times. “The navy will be feeling this expenditure for several years.”

The growing cost of the conflict is also placing pressure on US President Donald Trump domestically. The war has disrupted a critical maritime trade corridor and pushed global oil prices above $100 a barrel, while US voters face rising petrol prices in a midterm election year.

Pentagon preparing $50 billion funding request

According to the Financial Times, the Pentagon is preparing to request as much as $50 billion in additional military spending from the White House and Congress in the coming days to support the war effort.

The supplemental funding request is expected to trigger a contentious debate on Capitol Hill as lawmakers from both parties question the scale and oversight of the spending.

Republican Senator Lisa Murkowski, a member of the Senate appropriations committee that oversees federal spending, warned that Congress would demand justification for the funding.

“The Pentagon must engage Congress,” Murkowski said on Thursday.

“You’ve got to be able to provide us with information, as requested, justification,” she said. “Don’t just take for granted that the Congress’s role is basically just to write the cheque.”

Any supplemental funding bill could face resistance in both chambers of Congress.

Republicans control the House of Representatives by a narrow margin, and fiscal conservatives have expressed concerns about large new federal spending commitments. The funding debate could become more complicated if the White House seeks to combine the military request with other measures, such as tariff relief for farmers.

Democratic lawmakers have also criticised the Iran war, arguing that the president launched military action without congressional authorisation.

War costs already exceeding $11 billion

Pentagon officials told senators earlier this week that the war had already cost more than $11 billion in the first six days of strikes, according to the Financial Times. Most of those costs were linked to munitions used in the campaign.

“The rounds we’re firing, Patriot rounds, Thaad rounds . . . these weapon systems, each round is millions of dollars,” Democratic Senator Mark Kelly, an Air Force veteran, said in an interview with MS Now.

Kelly said the economics of the conflict highlight a growing asymmetry between US weapons and the systems deployed by Iran.

Meanwhile, Iran is deploying Shahed drones, which US intelligence officials say can be produced for about $30,000 each, he said.

“The math on this doesn’t work,” Kelly added.

Congress is expected to receive a classified briefing on the munitions expended in the war in the coming days, according to a person familiar with the matter cited by the Financial Times.

Also Read | Iran says war could destroy global economy as Trump vows to 'finish' job

Concerns over US weapons stockpiles

US officials have warned in recent years that the pace of weapons use in modern conflicts could exceed the country’s ability to replenish its stockpiles.

Those concerns have intensified as Washington faces the possibility of future confrontations with major military powers such as Russia or China, which could require large volumes of advanced weapons.

Murkowski said previous US administrations had already faced limits when attempting to support allies.

She recalled that Washington had told Ukraine and European partners that the United States would provide more weapons but lacked sufficient stockpiles.

“With the level of inventory that [US operations in Iran are] going through on a daily basis, I think we all have reason to ask good questions about how we are doing on munitions,” she said.

White House and Pentagon defend stockpile levels

The Trump administration has pushed back against suggestions that US military stockpiles are running low.

Defence Secretary Pete Hegseth said last week that the United States has sufficient munitions to sustain the campaign.

“We’ve got no shortage of munitions,” Hegseth said. “Our stockpiles of defensive and offensive weapons allow us to sustain this campaign as long as we need to.”

White House press secretary Karoline Leavitt also said the military retains ample supplies.

“The US military has more than enough munitions, ammo and weapons stockpiles to achieve the goals of Operation Epic Fury laid out by President Trump and beyond,” Leavitt said.

She added that the president continues to press defence contractors to accelerate weapons production.

Tomahawk missiles central to the campaign

Tomahawk missiles, subsonic cruise missiles carrying a 1,000-pound warhead, have played a central role in US strikes during the conflict.

The weapons are manufactured by US defence contractor RTX and cost about $3.6 million per missile.

US procurement of the missiles has been relatively limited in recent years. The military purchased 322 Tomahawks over the past five years, including 57 missiles allocated for fiscal year 2026 at a cost of $206.6 million.

The pace of usage in the current war could significantly exceed that rate of production.

According to the Center for Strategic and International Studies (CSIS), the US used 168 Tomahawk missiles in the first 100 hours of the war that began on February 28.

The US military had already used at least 124 Tomahawks in operations against Houthi militants in Yemen and Iranian nuclear facilities in 2024 and 2025, according to the Financial Times.

More than two dozen missiles were used in a strike on Iran’s nuclear facility at Isfahan, General Dan Caine, chairman of the Joint Chiefs of Staff, said last June.

Lawmakers question long-term cost

Lawmakers in both parties have warned that the financial and military cost of the conflict could continue to rise.

Ron Wyden, the top Democrat on the Senate finance committee, said the war is already imposing a large financial burden.

The United States is spending “many billions” on a war that is increasingly unpopular with voters, Wyden said.

The cost of the conflict “goes up practically as we talk”, he said.

“It’s an astronomical sum.”