Barrel (unit) continued to use the same size barrels. In the worldwide oil industry, an oil barrel is defined as 42 US gallons, which is about litres or 35 imperial gallons. Oil companies that are listed on American stock exchanges typically report their production in terms of volume and use the units of bbl, Mbbl (one thousand barrels), or MMbbl (one million barrels) and occasionally for widest comprehensive statistics the Gbbl (or sometimes Gbl) denoting a billion. There is a conflict concerning the units for oil barrels (see ). For all other physical quantities, according to the International System of Units, the
Barrel of oil equivalent which is 1,000BOE. Other common multiples are the million barrels per day, MMboed (or MMBOED, MMboepd), used to measure daily production and consumption, and the BBOe (also BBOE) or billion barrel of oil equivalent, representing 10 barrels of oil, used to measure petroleum reserves. Metric users may talk of the tonne of oil equivalent (TOE), or more often million TOE (MTOE). Since this is a measurement of weight, any conversion to barrels of oil equivalent depends on the density of the oil in question, as well as the energy content. Typically 1 tonne of oil has a volume of 6.8-7.5