How many gallons of oil in a barrel?
It depends on what you mean by barrel. The unit barrel used in the petrochemicals industry (usually to measure liquid volume, or volumetric flow rates) is equal to 42 U.S. gallons (about 35 imperial gallons), [1] however, actual barrels used to transport petrochemicals are 55 U.S. gallons (44 imperial gallon drums are used in the U.K.).