Convert Barrels (Petroleum)

Petroleum Barrel - The standard barrel of crude oil or other petroleum product (abbreviated bbl) is 42 US gallons (34.972 Imperial gallons or 158.987 L). This measurement originated in the early Pennsylvania oil fields, and permitted both British and American merchants to refer to the same unit, based on the old English wine measure, the tierce.

Earlier, another size of whiskey barrel was the most common size; this was the 40 US gallons (33.3 imp gal; 151.4 L) barrel for proof spirits, which was of the same volume as 5 US bushels. However, by 1866 the oil barrel was standardized at 42 US gallons.

Oil has not actually been shipped in barrels since the introduction of oil tankers, but the 42-US-gallon size is still used as a unit for measurement, pricing, and in tax and regulatory codes. Each barrel is refined into about 19.74 gallons of gasoline, the rest becoming other products such as jet fuel and heating oil, using fractional distillation. The current standard volume for barrels for chemicals and food is 55 US gallons (46 imp gal; 208 L).