There are 31.5 US fluid gallons in a fluid barrel and 42 US gallons in an oil barrel. There are 26.25 US dry gallons in a dry barrel. To convert from gallons to barrels, multiply the gallon value by the conversion factors that are listed below.
1 Gallon [Fluid] = 0.0317460317 Barrel [Fluid]
1 Gallon [Fluid] = 0.0238095238 Barrel [Oil]
1 Gallon [Dry] = 0.03809559265 Barrel [Dry]
Gallon is an imperial and US Customary unit. There is one type of gallon in imperial system and 2 types (liquid and dry) in US Customary system. The abbreviation is "gal".
Barrel is a volume unit. The abbreviation is "bbl".