Barrel As used in the measurement of petroleum products, a standard barrel contains 42 U.S. gallons, or approximately 35 imperial gallons. By rhys|2014-10-08T18:41:36+00:00October 8th, 2014|Comments Off on Barrel Share This Story, Choose Your Platform! FacebookTwitterRedditLinkedInWhatsAppTumblrPinterestVkXingEmail About the Author: rhys