What is the size of an oil drum?

An oil drum, or one barrel of oil, is a standard unit that contains 42 U.S. gallons of liquid. One barrel of crude oil produces about 45 gallons of finished product because distillates and other products are added to the oil during the refining process.

One barrel of oil is used to make 19 gallons of gasoline, 12 gallons of diesel fuel, four gallons of jet fuel and two gallons of liquefied petroleum gases in the United States. In California, more than 51 percent of a crude oil barrel goes to gasoline, 15 percent is made into distillate fuel oil and more than 12 percent is made into jet fuel.