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 (unit) US barrels for the benefit of American investors and oil marketers. They will generally quote prices in Canadian dollars per cubic metre to other Canadian companies, but use US dollars per barrel in financial reports and press statements, making it appear to the outside world that they operate in barrels. Companies on the European stock exchanges report the mass of oil in metric tonnes. Since different varieties of petroleum have different densities, however, there is not a single conversion between mass and volume. For example, one tonne of heavy distillates might occupy a volume of 256 US gallons (6.1 bbl).