How many ounces make up a gallon Featured886 viewsJuly 17, 2020Generalconvert gallon measure multiply ounce 0 authorise2050@gmail.com587 June 10, 2020 0 Comments One gallon equals 128 fluid ounces. To convert gallons into fluid ounces, multiply the gallon value by 128. habbaba Edited question July 17, 2020 1 Answer ActiveVotedNewestOldest 0 habbaba534 Posted June 22, 2020 0 Comments One gallon equals 128 fluid ounces. habbaba Answered question June 22, 2020 Register or Login