	"Spinostropheus" was a relatively small theropod. In 2010, Gregory S. Paul estimated its length at 4 metres (13 feet), and its weight at 200 kg (441 lbs). In 2012 Thomas R. Holtz Jr gave a length of 6.2 meters (20.3 feet). In 2016 Molina-Pérez & Larramendi gave a higher estimation of 8.5 meters (28 feet) and 600 kg (1.323 lbs) for the MNHN specimen known from an ulna.