---
title: "Dinosaur Size Comparison: Real Sizes Next to a Human"
description: "Dinosaur size comparison: Diplodocus, Spinosaurus, T. rex, Triceratops, Stegosaurus, Velociraptor and more, from real specimens, beside an adult human."
url: "https://sizeitup.us/sizes/dinosaurs"
language: "en-US"
published: "2026-11-05"
modified: "2026-11-05"
---

# Dinosaur size comparison

How big were dinosaurs next to a person? These sizes come from real specimens, measured nose to tail or to the top of the head from museum skeletons and published papers, with an adult man for scale. Each name opens its own size page with the source and exactly what was measured.

Published November 5, 2026

## Dinosaurs, smallest to largest

The dinosaurs to scale, smallest to largest, with an adult man in orange.

| Object                                                                                                                                                         | Size         | vs Adult man    |
| -------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------ | --------------- |
| [Archaeopteryx](https://sizeitup.us/sizes/archaeopteryx) – The Jurassic feathered dinosaur often called the first bird, measured nose to tail.                 | 50 cm long   | 29% of the size |
| [Adult man (US average)](https://sizeitup.us/sizes/human) – An average adult man, for scale.                                                                   | 1.75 m tall  | –               |
| [Velociraptor](https://sizeitup.us/sizes/velociraptor) – A feathered predator from Cretaceous Mongolia, measured nose to tail.                                 | 1.8 m long   | about the same  |
| [Stegosaurus (Sophie, NHM London)](https://sizeitup.us/sizes/stegosaurus) – Sophie, the most complete Stegosaurus skeleton ever found. Measured nose to tail.  | 5.6 m long   | 3.2× bigger     |
| [Ankylosaurus](https://sizeitup.us/sizes/ankylosaurus) – The armoured dinosaur with a bony tail club, measured nose to tail.                                   | 8 m long     | 4.6× bigger     |
| [Triceratops](https://sizeitup.us/sizes/triceratops) – The three-horned plant-eater of Late Cretaceous North America, measured nose to tail.                   | 9 m long     | 5.1× bigger     |
| [Tyrannosaurus rex (SUE, Field Museum)](https://sizeitup.us/sizes/t-rex) – SUE, one of the largest and most complete T. rex skeletons. Measured snout to tail. | 12.34 m long | 7.1× bigger     |
| [Giraffatitan (Berlin skeleton)](https://sizeitup.us/sizes/giraffatitan) – A long-necked sauropod from Jurassic Tanzania, mounted with its head held high.     | 13.27 m tall | 7.6× bigger     |
| [Spinosaurus](https://sizeitup.us/sizes/spinosaurus) – The sail-backed river hunter of Cretaceous North Africa, measured nose to tail.                         | 14 m long    | 8× bigger       |
| [Diplodocus (Dippy, NHM London)](https://sizeitup.us/sizes/diplodocus) – Dippy, the Natural History Museum's famous Diplodocus cast, measured head to tail.    | 26 m long    | 15× bigger      |

Guess sizes like these every day in Prehistoric Giants, a prehistoric size comparison game.

[Play today's Prehistoric Giants puzzle](https://sizeitup.us/play/prehistoric)