(CNN)-- US Defense Secretary Pete Hegseth revealed that the war against Iran has cost the United States $37.5 billion, but experts previously told CNN that the cost is likely much higher.

Democratic Senator Dick Durbin asked Hegseth during a budget hearing whether he expects this cost to rise now that the ceasefire between the United States and Iran has effectively ended.

Hegseth replied that part of the $37.5 billion covers expenses such as soldiers' meals through the end of the fiscal year.

In a related context, analysts estimated in March that the war against Iran costs US taxpayers more than $890 million per day, based on known military operations and congressional cost estimates.

This spending includes air and naval operations, ground forces, weapons systems, and missile interception, with the first phase of the conflict being the most costly.

In May, Jules Hurst, the comptroller of the Department of Defense (the Pentagon), estimated the approximate cost at around $29 billion.

Last month, preliminary figures from an analysis by the Center for Strategic and International Studies indicated that the conflict has cost the Pentagon about $40 billion, but this figure does not include operational costs already included in the department's fiscal year 2026 budget, which exceeds $1 trillion, according to Mark Cancian, a senior adviser at the center, who spoke to CNN.