Barrel of oil equivalent
The barrel of oil equivalent (BOE) is a unit of energy based on the approximate energy released by burning one barrel (42 U.S. gallons or 158.9873 litres) of crude oil. The U.S. Internal Revenue Service defines it as equal to 5.8 × 106 BTU. The value is necessarily approximate as various grades of oil have slightly different heating values.
A commonly used multiple of the BOE is the kilo barrel of oil equivalent (kboe or kBOE), which is 1,000 times larger.
Other common multiples are the BBOe, (also BBOE), or billion barrel of oil equivalent, representing 109 barrels of oil, used to measure petroleum reserves, and million barrels per day, MMbd (or MMBD), used to measure daily production and consumption. Also used is the Mtoe, or Millions of tonnes of oil equivalent, a metric measurement equivalent to approximately 0.006841 BBOE.
See also 
- Conversion of units#Energy
- Cubic mile of oil
- Energy density
- Heat of combustion
- Miles per gallon gasoline equivalent
- Ton of oil equivalent
- IRS publication
- Table AR-1 USGS World Petroleum Assessment 2000, Description and results, USGS World Energy Assessment team
- USGS World Petroleum Assessment retrieved 16 October 2008
- Energy Infocard retrieved 16 October 2008
- Conversion Factors retrieved 16 October 2008