Because 1 barrel = 158.98 liters =42 gallons. American 1 gallon =3.785 liters, British 1 gallon =4.546 liters. If the volume is converted into weight, it is related to the density of crude oil. Assuming that the density of crude oil in a local area is 0.99 kg/L, the weight of a barrel of crude oil is158.98× 0.99 =157.3902 kg = 0.157 tons.

The conversion relationship between tons and barrels is:

1 ton is about 7 barrels. If the oil quality is light (thin), 1 ton is about 7.2 barrels or 7.3 barrels. Although there is a fixed conversion relationship between tons and barrels, because tons are quality units and barrels are unit of volume, the density of crude oil is very different. If different units are used in the transaction, the results will be different.

Gallons and liters are two relatively small units of measurement for refined oil. Gas stations in the United States and Europe are usually in gallons, while gas stations in China are priced in liters.