Convert Barrel (Oil) (bbl (oil)) to Tun (tun) instantly.
About these units
Barrel (Oil) (bbl (oil))
An oil barrel is defined as 42 US gallons, or 158.987 liters, and is a fundamental unit in the petroleum industry. This peculiar size traces back to the early Pennsylvania oil fields, where producers standardized whiskey barrels and modified wooden casks for oil transport. The need for consistent trade volumes cemented the 42-gallon barrel as the industry norm. Today, global oil production, pricing, and consumption are expressed in barrels—from daily OPEC reports to energy market forecasts. Even though oil is no longer physically shipped in barrels, the unit remains deeply embedded in international energy economics.
Tun (tun)
A tun is a historical large cask unit commonly used in the wine and brewing industries, typically defined as 252 imperial gallons, or roughly 954 liters. It represented one of the largest standardized cask sizes in medieval and early modern Europe. Originally used for transporting wine, ale, and oil, the tun played an important role in commerce and maritime trade. Because taxes and tariffs were often levied per tun, its definition became central to economic regulation. The size also reflected the maximum volume that could be reliably transported in wooden casks without structural failure. Though obsolete today, the tun provides valuable insight into historical logistics, taxation, and the evolution of standardized container sizes in European trade networks.