The Barrel of Oil Equivalent (BOE) is an energy unit that is convenient for expressing the quantity of oil or gas in common terms. It is equivalent to 5.8 million BTU or 6.1 GJ. In terms of oil, a BOE is the energy released (approximately) by burning 42 US gallons (one barrel) of crude oil, and in terms of natural gas is the energy equivalent of about 6000 cubic feet.