On September 15, 2026, the nonpartisan Congressional Budget Office released its estimate of what the war with Iran has cost the Defense Department: $38.1 billion from February 28 through August 1, and roughly $2 billion to $3 billion for each additional month, with more during escalations. CBO said July alone, a month of repeated strikes, cost about $3 billion. The analysis was requested by Rep. Brendan Boyle (D-PA), the top Democrat on the House Budget Committee.
The largest piece is replacing munitions. “CBO estimates that the cost to replace the munitions expended through August 1, 2026, is $21.7 billion: $7.3 billion for the land-attack cruise missiles, $13.1 billion for the missile defense interceptors, and $1.2 billion for other munitions,” the report said. Comparing reported interceptor use with what the Pentagon has bought, CBO concluded that “the United States has probably used between one-half and two-thirds of its inventory of those munitions since June 2025.” It said rebuilding that inventory “would probably take at least five years,” and warned: “The shortfall would become especially problematic if a conflict arose with an opponent whose arsenal included large numbers of ballistic and cruise missiles.”
The estimate is incomplete by design. The Pentagon “did not respond to CBO's requests for information,” so CBO relied on government databases and public reports and said its figures are subject to “considerable uncertainty.” AP called the department's refusal a break from norms. The estimate excludes repairs to damaged U.S. bases, which CBO said it could not price without information about “damaged or destroyed equipment and property,” as well as borrowing costs, future veterans' care and costs borne by other agencies. CBO also said its category estimates are “not directly comparable or summable.”
On the economy, CBO projected that the war will add roughly 0.5 percentage points to personal consumption expenditures inflation in the first quarter of 2027 compared with its prewar forecast, driven largely by energy prices after disruptions in the Strait of Hormuz and the Red Sea. Roll Call reported the analysts found that more than 40 percent of that inflation measure in the second quarter of 2026 was due to higher energy costs.
The report also scrutinized the White House's pending $67.1 billion supplemental request for the Pentagon, finding that $42.3 billion of it is directly related to the war and that $12.1 billion is for classified programs, a larger classified share than past war requests. Congress has not approved that request. The Center Square reported that no money has been appropriated specifically for the war and that the services have been paying from training and maintenance accounts; Roll Call reported the Pentagon's inspector general found the same shift of funds.
The administration disputed the premise. White House spokeswoman Anna Kelly said, “The United States Military has more than enough munitions, ammo, and stockpiles to serve all of the Commander-in-Chief's strategic goals and beyond.” Pentagon spokesman Sean Parnell said, “We have everything required to strike at the time and place of the President's choosing,” and a Pentagon statement called claims of shortages false. Trump has said the U.S. has “virtually unlimited” ammunition. A senior Pentagon official told The Center Square the inspector general “did not have access to all relevant information.” Boyle said, “Donald Trump and Republicans have spent years telling Americans that we cannot afford to help families here at home, but apparently they can find tens of billions of dollars, and potentially much more, for a reckless war that is leaving Americans to pay the price.”
CBO's figure is an independent estimate covering a month more than the inspector general's $33.4 billion, which relied on the Pentagon's own data; the two measure different things and should not be added together (see Pentagon Watchdog Finds the Iran War Left 'Strategic Inventory Shortfalls' in Munitions as Trump Boasts of Record Weapons Production and New York Times: The Iran War Has Drained U.S. Weapons Stockpiles Below the Level Needed to Confront a Near-Peer Adversary, at a Cost Nearing $1 Billion a Day).
Update (October 28, 2026): At a midterm rally in Lubbock, Texas, on October 27, Trump told the crowd that when he was asked earlier when the war in Iran would end, he answered, “Whenever I want it to end.” He said, “It could be over whenever I want it to be over,” and, “It'll be very quick, but we have to have it end properly,” according to the Roll Call Factbase transcript.
Update (October 29, 2026): a U.S. Central Command estimate dated October 16 and provided to Congress puts the war's cost to the military at “at least $47.1 billion as of mid-October,” CBS News reported; The Hill obtained the same estimate. CBS reported about $29 billion to replace expended munitions, $6.1 billion for lost equipment and about $11.9 billion in incremental costs such as support for service members; The Hill also listed $7.6 billion in Air Force support costs, so the components as the two outlets report them should not be added together. The estimate excludes damage to U.S. bases in the Middle East.
Defense Secretary Pete Hegseth told lawmakers about three months earlier that the war had cost around $37.5 billion, CBS reported, and The Hill said the Pentagon put the cost at about $43.6 billion in early September. CENTCOM's figure is the military's own accounting through mid-October; CBO's $38.1 billion is an independent estimate through August 1, so the two are not directly comparable. CBS said it had asked the Pentagon for comment.