How heavy were the dinosaurs really?
Dinosaur masses are estimates from bone dimensions and modelled body volume, and they have fallen sharply as the models improved.
Almost exactly Triceratops
8 t is heavier than 3 of the 9 references on this page.
Reference figures are measurements and are rounded; the unit conversion behind them is exact.
| Reference | Size | Yours ÷ theirs | Note |
|---|---|---|---|
| velociraptor | 0.015 t | 533× | |
| average man (US) | 0.0906 t | 88.3× | |
| Allosaurus | 2 t | 4× | |
| Triceratops | 8 t | 1× | |
| T. rex | 8 t | 1× | |
| Brachiosaurus | 35 t | 0.229× | |
| Patagotitan | 57 t | 0.14× | |
| Argentinosaurus | 70 t | 0.114× | The upper end of a wide range |
| blue whale | 150 t | 1/18.8 |
Worth knowing
- No dinosaur we have good evidence for matched a blue whale. Water supports weight that legs cannot.
- Estimates for Argentinosaurus have ranged from 50 to 100 tonnes depending on the method — the fossil is only about 10% complete.
Frequently asked
How do you weigh a dinosaur?
Two ways: scale the circumference of the weight-bearing limb bones against living animals, or build a 3D model of the skeleton, wrap estimated soft tissue around it and compute the volume. The two methods now broadly agree.
How much did a T. rex weigh?
Current estimates centre on 8 tonnes, with the largest specimen, Scotty, put at about 8.8. Older figures of 5 to 6 tonnes came from thinner reconstructions.