Sourced comparison
Dinosaur size comparison chart
How long were some familiar dinosaurs? This chart brings together reported length estimates for 14 non-avian dinosaurs and links each figure to the sources used on its profile.
How to read these estimates
Lengths are estimates, not tape measurements. Fossils are often incomplete, and researchers may use different specimens and reconstruction methods. The figures below summarize the linked reference for each animal; they are not precise rankings or a claim that every individual reached the largest reported size. Height and mass are not directly comparable to body length.
This chart covers selected non-avian dinosaurs. Pterosaurs such as Quetzalcoatlus were flying reptiles, and marine reptiles such as Mosasaurus were not dinosaurs, so they are not mixed into this table.
| Dinosaur | Group | When it lived | Reported size estimate | Profile source |
|---|---|---|---|---|
| Brachiosaurus | Sauropod | Late Jurassic, about 152–145 million years ago. | The Natural History Museum estimates about 22 m in length, but notes that complete skeletons are lacking and reconstructions partly use a related species. | Natural History Museum: Brachiosaurus |
| Spinosaurus | Theropod | Late Cretaceous, about 99–94 million years ago. | Estimated at about 14 m long, making it one of the longest known predatory dinosaurs. The estimate is uncertain because no complete skeleton is known. | Natural History Museum: Spinosaurus |
| Giganotosaurus | Theropod | Late Cretaceous, about 100–95 million years ago. | Estimated at around 13 m long. No complete skeleton has been found, so its total size and mass remain uncertain. | Natural History Museum: Giganotosaurus |
| Tyrannosaurus Rex | Theropod | Late Cretaceous, about 68–66 million years ago. | Usually estimated at about 12 m long; the largest known individuals approached 13 m. The largest specimens are estimated to have exceeded 8 tonnes. | Natural History Museum: Tyrannosaurus |
| Therizinosaurus | Theropod | Late Cretaceous, about 70 million years ago. | Estimated at about 10 m long. Its hand claws reached around 50 cm, but the body estimate is based on incomplete remains and relatives. | Natural History Museum: Therizinosaurus |
| Allosaurus | Theropod | Late Jurassic, about 152–145 million years ago. | The Natural History Museum lists a length of about 9.7 m and an estimated mass of 2.7 tonnes; individual size varied. | Natural History Museum: Allosaurus |
| Triceratops | Ceratopsian | Late Cretaceous, about 68–66 million years ago. | Estimated at about 9 m long and around 10 tonnes; body size varied among individuals. | Natural History Museum: Triceratops |
| Parasaurolophus | Ornithopod | Late Cretaceous, about 77–73 million years ago. | Estimated at about 9 m long. The Natural History Museum lists a mass near 5 tonnes; both figures are reconstructions. | Natural History Museum: Parasaurolophus |
| Stegosaurus | Stegosaur | Late Jurassic, about 152–145 million years ago. | Estimated at about 9 m long. Fossils preserve plates and tail spikes, but body-size estimates vary among specimens. | Natural History Museum: Stegosaurus |
| Ankylosaurus | Ankylosaur | Late Cretaceous, about 68–66 million years ago. | Estimated at about 8 m long; some estimates put its mass near 8 tonnes. The animal is known from incomplete remains. | Natural History Museum: Ankylosaurus |
| Carnotaurus | Theropod | Late Cretaceous, about 71–69 million years ago. | Estimated at about 8 m long. The skeleton is incomplete, so parts of its body reconstruction remain uncertain. | Natural History Museum: Carnotaurus |
| Dilophosaurus | Theropod | Early Jurassic, about 184 million years ago. | Estimated at about 7 m long and 400 kg; these are reconstructions from fossil material, not measurements of a complete skeleton. | Natural History Museum: Dilophosaurus |
| Pachycephalosaurus | Ornithopod | Late Cretaceous, about 69–66 million years ago. | Estimated at about 3 m long and 450 kg; these measurements are reconstructions from fossils. | Natural History Museum: Pachycephalosaurus |
| Velociraptor | Theropod | Late Cretaceous, about 74–70 million years ago. | About 1.8 m long and an estimated 7 kg in the Natural History Museum reference; estimates vary by specimen. | Natural History Museum: Velociraptor |
Each linked profile includes a short summary, location, size and diet notes, and its source list. Read our editorial and sourcing policy for how we describe estimates and review sources.