The oil barrel, unit of volume
The oil barrel holds exactly 158.987294928 liters, that is 42 US gallons. It is the unit in which crude oil is priced, taxed and counted the world over, and it measures nothing that anybody actually moves.
It comes from a wine cask. The Pennsylvania oil fields borrowed the English tierce, a barrel of 42 gallons, and the Petroleum Producers Association settled on that size in 1872 so that buyer and seller would stop arguing over the cooper's work. Oil has not travelled in barrels for more than a century: it moves by pipeline and tanker, and the barrel survives as a pure unit of account. A price per barrel therefore refers to no container at all.
The oil barrel in other units
| 1 bbl | 0.158987 m³ |
| 1 bbl | 158.987 l |
| 1 bbl | 15,899 cl |
| 1 bbl | 158,987 ml |
| 1 bbl | 42 gal |
| 1 bbl | 34.9723 gal UK |
| 1 bbl | 336 pt |
| 1 bbl | 5,376 fl oz |
| 1 bbl | 5,596 fl oz UK |
| 1 bbl | 168 qt |
| 1 bbl | 139.889 qt UK |
| 1 bbl | 279.779 pt UK |
| 1 bbl | 672 cup |
| 1 bbl | 635.949 cup metric |
| 1 bbl | 794.936 cup JP |
| 1 bbl | 10,752 tbsp |
| 1 bbl | 10,599 tbsp metric |
| 1 bbl | 7,949 tbsp AU |
| 1 bbl | 32,256 tsp |
| 1 bbl | 31,797 tsp metric |
| 1 bbl | 1,590 dl |
| 1 bbl | 88.135 sho |
| 1 bbl | 881.35 go |
Frequently asked questions
How many liters are in a barrel of oil?
158.987294928 exactly, which everyone rounds to 159. In cubic meters it is 0.159, so a thousand barrels make almost exactly 159 cubic meters.
Why 42 gallons and not a round number?
Because the size was inherited rather than chosen: the tierce of the English wine trade held 42 gallons, and the Pennsylvania producers took it as it was in 1872. A full 42-gallon cask weighs about 136 kilograms, which is roughly what two men could roll.
Is every barrel an oil barrel?
No, and the word alone is not a measure. The US liquid barrel is 31.5 gallons, the US beer barrel 31, and the British beer barrel 36 imperial gallons, which is 163.7 liters. Only the oil barrel is 42.