"Barosaurus" was an enormous animal, with some adults measuring more than 25–27 meters (82–89 feet) in length and weighing about 12–20 metric tons (13–22 short tons). There are some indications of even larger individuals, such as the enormous vertebra from the BYU 9024 specimen, which is 1.37 meters (4.5 ft) long. Assuming it belongs to "Barosaurus", this was an animal that was 48 meters (157 ft) long and around 66 metric tons (73 short tons) in weight making it one of the largest known dinosaurs, with a neck length of at least 15 meters (49 ft) according to Mike Taylor. In 2020 Molina-Perez and Larramendi estimated it to be slightly smaller at 45 meters (148 ft) and 60 metric tons (66 short tons). "Barosaurus" was differently proportioned than its close relative "Diplodocus", with a longer neck and shorter tail, but was about the same length overall. It was longer than "Apatosaurus", but its skeleton was less robust.