Barrel and ton are two commonly used units of crude oil measurement. The unit of crude oil measurement in western countries such as the Organization of Petroleum Exporting Countries, Europe and America is expressed in barrels, while China and Russian countries often use tons (t) as the unit of crude oil measurement. The conversion relationship between tons and barrels is: 1 ton (crude oil) =7.35 barrels (crude oil).

However, since the ton is the unit of mass and the barrel is unit of volume, the density of crude oil varies widely (0.75~ 1), different results will be obtained if different units are used in crude oil trading. Gallons and liters are two relatively small units of measurement for refined oil. Gas stations in western countries such as Europe and America are usually measured in gallons, while gas stations in China are priced in liters. The conversion relationship between liter and gallon is 1 liter =0.264 gallon. 1 gallon (USA) =3.7854 liters.