How many gallons of beer are in a standard U.S. keg of beer?
Most U.S. brewers sell beer in 1⁄2 barrels of 15.5 gallons, 1⁄4 barrels of 7.75 gallons, and 1⁄6 barrels of 5.17 gallons. Since keg sizes are not standardized, the keg cannot be used as a standard unit of measure for liquid volumes. This size standard varies from country to country and brewery to brewery with many countries using the metric system rather than U.S. gallons. A typical keg (half-barrel) with a single opening in the center of the top end A keg, or half-barrel is a 15.5 U.S. gallon vessel. A quarter-barrel has a volume of 7.75 U.S. gallons. Generally a keg is a vessel smaller than a barrel; thus, it is 30 gallons or smaller
If you mean a half barrel keg: 15.5 U.S. gallons 12.91 imperial gallons