Ankylosaurus. Iguanodon. Brontosaurus. An average Stegosaurus was about 12 m (40 ft) long and about 2.75 m (9 ft) tall. Stegosaurus weighed about 2,000 kg or 6,800 pounds (around 3 tons!) Stegosaurus' s front feet each had five toes and there were three toes on each back foot.nkylosaurus. Iguanodon. Brontosaurus. An average Stegosaurus was about 12 m (40 ft) long and about 2.75 m (9 ft) tall. Stegosaurus weighed about 2,000 kg or 6,800 pounds (around 3 tons!) Stegosaurus' s front feet each had five toes and there were three toes on each back foot.