The Defense Department is the government's largest consumer of petroleum products, like gasoline, diesel and jet fuel.
And if it costs $100 to fill up an SUV, just imagine what it takes to gas up a stealth bomber.
The Air Force is the biggest user of fuel, consuming 71 percent of the military's gallons. Those huge aircraft that transport personnel and equipment all over the world are not economy boxes. Take the C-5 Galaxy, which can carry 135 tons: It gets .07 miles per gallon.
And the armies on the ground in Iraq and Afghanistan aren't driving hybrids. In Iraq alone, the military burns more than a million and a half gallons a day.
Lt. Col. Brian Maka puts the Pentagon's fuel expenses in perspective. "Generally, a $1 increase in the price of a barrel of oil on the open market translates into an increase for the whole department of $130 million," Maka says.
Over the last six months, oil prices have increased by roughly $50 a barrel. That translates into a huge spending increase.
The Defense Department prepares its budget 18 months in advance and had no way of predicting that oil prices would increase this much in such a short period of time.
"The implication of that is since these fuel costs go into our ... operations and maintenance budgets, those are going to be the budgets that are hit the hardest," says Dov Zakheim, a former controller for the Defense Department. "The problem is that those are the very same budgets that are ... paying for our operations in places like Iraq and Afghanistan. So it's kind of a vicious circle, and a very, very difficult one to deal with."
And it's probably not going to get any better any time soon.
"We anticipate over the next three months that the increase in fuel costs for the department [will be] $1.2 billion," Maka says, adding that the Defense Department will likely have to ask Congress for additional funding.
In Congress, several senators have proposed that Iraq should start paying for some of the military's fuel costs because of its large oil reserves.
But Zakheim says he doesn't think that's going anywhere.
"I'm just not sure that the Iraqi government would respond the way we might hope them to," he says.
Instead, Zakheim thinks the Pentagon will throw its considerable research and development resources into finding alternative fuels.
"My guess is that we are going to see something like other cases in the past where the Pentagon forged ahead in the science and technology world because it was impelled to do so," he says. "After all, the Internet did start with the Pentagon."
But that kind of research and development takes time. Meanwhile, the meter is still running — faster and faster.