US War With Iran Costs $45.1 Billion—and the Bill is Incomplete: Report

The US conflict with Iran has run up an estimated $45.1 billion bill. Even that does not capture the full financial damage.

The Pentagon communicated the estimate to Congress on Friday, according to CNN, which cited two sources familiar with the matter. The total comprises $43.6 billion in war-related expenditure through September 3 and another $1.5 billion for extra fuel.

Missing from the calculation are the costs of repairing damaged US military bases and buildings, one source told CNN. The assessment also does not provide lawmakers with a detailed account of indirect military-operation costs.

A Rising Bill, an Incomplete Account

The latest estimate exceeds the Pentagon’s July figure of $37.5 billion. It is also higher than the Congressional Budget Office’s estimate of approximately $38 billion through August 1.

Those figures cover different periods and should not be treated as directly comparable assessments of the same expenditure.

In its September 15 report, Estimating the Cost of Combat Operations Against Iran, the CBO included operational, logistical and sustainment costs. These covered replacing expended ammunition and equipment lost in battle, additional flying hours, other military operations and higher fuel expenditure.

But the budget office attached a significant qualification: its estimate carried “considerable uncertainty”.

The Department of Defense had not responded to its requests for information, the CBO said, leaving it to rely on government databases and public reporting.

Its calculation also excluded spending by other parts of the federal government and certain expenses already accounted for in the federal budget.

Another Month, Another $2–3 Billion

The next addition to the bill will depend on the intensity of fighting.

The CBO estimated that another month of conflict would cost around $2 billion if violence remained at the levels seen in May and June. A return to July’s approximate intensity could push monthly costs to $3 billion.

“Monthly costs could be higher still if the violence escalated further,” it warned.

The military consequences extend beyond expenditure. The CBO identified the heavy use of missile-defence interceptors as a major opportunity cost, warning that the US would be left with reduced stocks for several years.

The Cost Reaches Consumers

Disruptions to oil and natural-gas shipments through the Strait of Hormuz, alongside pressure on shipping through the Red Sea, have widened the conflict’s economic impact.

According to the CBO, those disruptions have contributed to higher global prices for crude oil and refined fuels, including petrol, diesel and jet fuel.

The agency estimated that higher energy prices added 2.3 percentage points to the annualised rate of overall personal consumption expenditures inflation in the second quarter of 2026. The PCE inflation rate stood at 5.3 per cent during that period.

The effects could persist into next year. For the first quarter of 2027, the CBO projected overall PCE inflation would be 0.5 percentage points above its February 2026 forecast. Core PCE inflation would be 0.3 percentage points higher.

It also projected higher US borrowing costs, with three-month Treasury bill rates nearly 0.2 percentage points above its earlier forecast in 2026.

Funding Requested Is Not Money Spent

The administration sought $87.6 billion in supplemental appropriations in June, including $67.1 billion for the Department of Defense.

Of the overall request, $42.3 billion appeared directly related to the conflict, according to the CBO.

Those are funding requests, rather than an additional tally of expenditure, and cannot simply be added to the Pentagon’s $45.1 billion estimate.

Further costs remain difficult to quantify. The CBO said potential spending on diplomacy and foreign aid would depend on the conflict’s outcome and could fall across several areas of government.

For Congress, the latest Pentagon figure offers an updated measure of military expenditure. The eventual bill will also depend on damaged infrastructure, depleted weapons stocks, the duration of fighting and the economic consequences beyond the battlefield.

With inputs from ANI