Giants of deep time
20 of the Largest Dinosaurs: Length Comparison
Compare Argentinosaurus, Diplodocus, Dreadnoughtus and other giants using published length estimates, with a source and a full atlas record for every dinosaur.
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How this list was selected
Selected large dinosaurs already in this atlas, ordered by the Natural History Museum’s genus-level reference lengths, checked on 3 September 2026. These are approximate reconstructions, not maximum specimen measurements or a complete world ranking. A longer animal need not be heavier. Equal values share the same size estimate; list positions do not resolve ties. The linked species is the atlas representative of that genus.
In this guide 20
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20 atlas recordsAbout 96–92 million years ago
Argentinosaurus
Argentinosaurus huinculensis
Estimated body length · genus reference≈ 35 mA handful of colossal vertebrae and limb bones indicate one of the largest land animals known.
South America · Present-day Argentina
Natural History Museum, London — argentinosaurus ↗
About 154–152 million years ago
Diplodocus
Diplodocus carnegii
Estimated body length · genus reference≈ 26 mA whip-like tail balanced an extremely long neck on this lightly built giant.
Western North America
Natural History Museum, London — diplodocus ↗
About 77 million years ago
Dreadnoughtus
Dreadnoughtus schrani
Estimated body length · genus reference≈ 26 mA relatively complete skeleton makes this giant titanosaur unusually measurable.
Floodplain woodland · Patagonia, Argentina
Natural History Museum, London — dreadnoughtus ↗
About 154–150 million years ago
Brachiosaurus
Brachiosaurus altithorax
Estimated body length · genus reference≈ 22 mLong forelimbs lifted its shoulders and neck toward the Jurassic canopy.
Western North America
Natural History Museum, London — brachiosaurus ↗
About 160–155 million years ago
Mamenchisaurus
Mamenchisaurus hochuanensis
Estimated body length · genus reference≈ 22 mNineteen elongated neck vertebrae placed nearly half the body's length in the neck, lightened internally by air spaces.
Lake and river woodland · Southwestern China
Natural History Museum, London — mamenchisaurus ↗
About 170–164 million years ago
Jobaria
Jobaria tiguidensis
Estimated body length · genus reference≈ 21 mA relatively short neck, strong limbs and primitive vertebrae belonged to a large non-neosauropod herbivore.
River floodplain · Niger
Natural History Museum, London — jobaria ↗
About 100–93.5 million years ago
Spinosaurus
Spinosaurus aegyptiacus
Estimated body length · genus reference≈ 14 mA sail-backed predator with dense bones and a paddle-like tail, adapted to life around water.
North African rivers and deltas
Natural History Museum, London — spinosaurus ↗
About 68–66 million years ago
Edmontosaurus
Edmontosaurus annectens
Estimated body length · genus reference≈ 13 mA broad duck bill and dense dental batteries processed huge amounts of vegetation.
Western North America
Natural History Museum, London — edmontosaurus ↗
About 99.6–97 million years ago
Giganotosaurus
Giganotosaurus carolinii
Estimated body length · genus reference≈ 13 mA giant narrow-skulled theropod shared its world with immense sauropods.
South America · Present-day Argentina
Natural History Museum, London — giganotosaurus ↗
About 113–110 million years ago
Acrocanthosaurus
Acrocanthosaurus atokensis
Estimated body length · genus reference≈ 12 mTall neural spines along the neck and back supported a muscular ridge rather than a paper-thin sail.
River plains and open woodland · North America
Natural History Museum, London — acrocanthosaurus ↗
About 129–122 million years ago
Amargasaurus
Amargasaurus cazaui
Estimated body length · genus reference≈ 12 mTwo rows of elongated neck spines made its profile unique, though their soft-tissue covering remains debated.
South America · Present-day Argentina
Natural History Museum, London — amargasaurus ↗
About 72–66 million years ago
Saltasaurus
Saltasaurus loricatus
Estimated body length · genus reference≈ 12 mSmall bony plates embedded in the skin showed that some titanosaurs carried armor.
Semi-arid floodplains · Argentina
Natural History Museum, London — saltasaurus ↗
About 68–66 million years ago
Tyrannosaurus
Tyrannosaurus rex
Estimated body length · genus reference≈ 12 mA deep skull, bone-crushing bite and keen senses made it one of the last giant theropods.
Western North America
Natural History Museum, London — tyrannosaurus ↗
About 130–125 million years ago
Baryonyx
Baryonyx walkeri
Estimated body length · genus reference≈ 10 mA crocodile-like snout and huge thumb claw equipped this theropod to catch fish and other prey.
River and lake country of Western Europe · Present-day Britain
Natural History Museum, London — baryonyx ↗
About 77–75 million years ago
Corythosaurus
Corythosaurus casuarius
Estimated body length · genus reference≈ 10 mA helmet-shaped hollow crest contained looping nasal passages that could shape resonant calls.
Coastal plains · Alberta, Canada
Natural History Museum, London — corythosaurus ↗
About 71–69 million years ago
Deinocheirus
Deinocheirus mirificus
Estimated body length · genus reference≈ 10 mHuge arms, a broad bill, a tall back and wide feet formed one of the strangest dinosaur silhouettes.
Mongolian Plateau
Natural History Museum, London — deinocheirus ↗
About 126–122 million years ago
Iguanodon
Iguanodon bernissartensis
Estimated body length · genus reference≈ 10 mA conical thumb spike and batteries of chewing teeth equipped this adaptable herbivore.
Western Europe
Natural History Museum, London — iguanodon ↗
About 70–66 million years ago
Therizinosaurus
Therizinosaurus cheloniformis
Estimated body length · genus reference≈ 10 mMeter-long hand claws belonged to a tall, feathered, pot-bellied herbivore.
Mongolian Plateau
Natural History Museum, London — therizinosaurus ↗
About 153–148 million years ago
Torvosaurus
Torvosaurus tanneri
Estimated body length · genus reference≈ 10 mA huge skull and unusually powerful three-fingered arms marked one of the largest megalosaurids.
River plains and open woodland · North America
Natural History Museum, London — torvosaurus ↗
About 155–145 million years ago
Allosaurus
Allosaurus fragilis
Estimated body length · genus reference≈ 9.7 mA lightweight skull and serrated teeth equipped this large predator for repeated slashing bites.
Western North America
Natural History Museum, London — allosaurus ↗
