Dinosaur Size Comparison: Prehistoric Giants

Written by Megan Martin
Published: November 8, 2021
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Dinosaur size comparison argentinousaurus Spinosaurus tyrannosaurus rex triceratops
Some of the largest animals ever have been dinosaurs, including the super-sized reptiles here.

Science has taught us a lot about dinosaurs from how they evolved to what they may have looked like. We even have pretty clear ideas of how big they were!  However, when you’re not standing face to face with one, it can be difficult to wrap your head around just how big they were – which is where a dinosaur size comparison guide helps.

Have you ever wondered if a dinosaur was bigger than you? How about if it was bigger than a house?  

We’ll answer these questions – and more! – in our complete dinosaur size comparison guide.

How Big are Dinosaurs?

How big are dinosaurs - Tyrannosaurus rex

Dinosaurs came in a variety of shapes and sizes.


Every year, our understanding of dinosaurs and their size changes. For instance, last year in 2020, scientists were able to uncover a dinosaur the size of a hummingbird –  a new species that now holds the title for smallest dinosaur ever. 

From some of the smallest animals to some of the largest, dinosaurs are a diverse group. So, how do these four prehistoric reptiles compare to one another – and you?

Argentinosaurus Size


The Argentinosaurus was one of the biggest dinosausr!

©DariuszSankowski / pixabay – License

The Argentinosaurus has been impressing the world with its size since its discovery in 1987. In fact, the very first fossil discovered from the Argentinosaurus was a single vertebra the size of an adult human! Scientists haven’t yet found a complete skeleton from an Argentinosaurus, but they’ve still been able to use fossils that have been found to estimate their size.

Have you ever noticed how long a bowling lane is? Scientists estimate that the Argentinosaurus was over twice as long as your standard bowl lane, making them over 130 feet long.

Just their hind legs alone are estimated to be 15 feet tall! This means that if the average person were to stand beside the Argentinosaurus, they would barely stand at the same height as the Argentinosaurus’ knee.

How does this compare to a house? Well, in the United States, the average two-story house is only around 20 feet tall. This means that the Argentinousaurus’ legs alone were nearly taller than a two-story home.

Argentinousauruses could also weigh up to 200,000 pounds. That’s more than two double-wide mobile homes and only 5,000 pounds less than the Statue of Liberty. 

Based on these measurements, it’s easy to see why the Argentinosaurus was one of the largest dinosaurs – as well as one of the largest land animals! Until recent years, it’s actually held the title for both, though several new discoveries have left scientists wondering just which dinosaur was the absolute largest.

Spinosaurus Size

How Long Were Dinosaurs on Earth

Spinosaurus was a semi-aquatic dinosaur from the Cretaceous period and was one of the largest carnivorous dinosaurs!

©Daniel Eskridge/Shutterstock.com

Can you imagine standing next to an animal that’s half the height of the Hollywood sign? The Spinosaurus is just that tall – around 23 feet.

However, for as tall as they are, they’re twice as long! With a snout-to-tail length of around 50 feet, the Spinosaurus is the same length as the average semi-truck. That’s also about the same length as one of the Hollywood sign’s letters. 

Despite these impressive measurements, the Spinosaurus would look like a toy compared to the Argentinosaurus. Height-wise, the Spinosaurus would only be a few feet taller than its hind legs. The Argrntinosuaurs would also be the same length as around two and a half Spinosaurus!

The Spinosaurus’ claim to fame is its large spines protruding from its back. These spikes alone grew to a minimum of 5’4”, the average height of an adult woman in the United States.

Tyrannosaurus Rex Size

Large Tyrannosaurus Rex in forest

The Tyrannosaurus Rex weighed the same as an African



©Fausto García-Menéndez / unsplash – License

Chances are, when you think of large dinosaurs, the T-rex is probably the first thing that comes to mind. After all, it’s been the face of a variety of franchises, and it’s arguably one of the most recognized dinosaurs around.

While the Tyrannosaurus Rex may not be the largest dinosaur, there’s still no doubt that it’s a humongous reptile. In fact, a full-grown male Tyrannosaurus Rex is estimated to be as tall as 12 feet. That’s the same height as an African elephant!

However, that’s not their more impressive measurement.

Based on fossil records, scientists have been able to estimate that the Tyrannosaurus Rex could be as long as 40 feet from their nose to their tail. This is around 10 feet shorter than the overall length of the Spinosaurus, but it’s still the same length as a London bus!

As a carnivore, the Tyrannosaurus Rex also maintained a heavyweight from muscles and a high-protein diet. Adult males had the potential to weigh as much as 15,500, which is also the same as a large African elephant. However, compared to the Argentinosaurus, the Tyrannosaurus Rex barely even begins to tip the scale. In fact, it would take over 13 stacked together to weigh the same as a single Argentinosaurus. It would only take around 3, however, to weigh the same as the Spinosaurus.

Triceratops Size

Triceratops fossil

The Triceratops is the most common dinosaur, although it’s not the largest.

©K. Mitch Hodge / unsplash – License

Like the T-Rex, the Triceratops is another well-known dinosaur. While they can look large and intimidating with their large horns and scaly fan at the top of their head, do you know just how big they really are?

Surprisingly, they’re actually the smallest dinosaur mentioned in this list!

Fossils show that the body length of the Triceratops was only 30 feet long – nearly half the length of the Spinosaurus and less than a quarter of the length of the Argentinousaurus. In fact, the Triceratops could almost fit perfectly in the space between the Argentinousaurus’ front and hind legs.

When it comes to weight, though, the Triceratops and the Tyrannosaurus Rex are well met. The Triceratops weighed up to around 11,000 pounds, making them about one Ford Taurus lighter than the Tyrannosaurus Rex. However, this is with maximum average weights, and it’s quite possible that many individuals of each species weighed the same.

They’re also similar in other measurements, as well. For example, where the Triceratops’ horns could grow up to 3 feet long, so could the Tyrannosaurus Rex’s foot from the heel to toe.

Human Vs. Dinosaur Size Comparison

Dinosaur size comparison
Humans don’t even come close to measuring up to some of the largest dinosaurs!

So, how does a human measure up to some of the world’s largest prehistoric giants?

The smallest dinosaur in this guide is the Triceratops. However, it’s still much bigger than a human. You may be able to see eye to eye with it due to the shape of its skull and body, but if you were to lay down beside it, you would only be around one-fifth of its length. One Triceratops also weighs the same as 55 average adult human males, or 65 adult human females.

However, when it comes to the Argentinosaurus, we’re no more than the average squirrel or mouse in its world. Standing side by side, the average human would barely come up to the Argentinosaurus’ knee. However, if we were to look to a scale, it would take nearly the entire population of Blue Ridge, Georgia to weigh the same as a single full grown Argentinosaurus. That’s around 1,00 people!

The photo featured at the top of this post is © metha1819/Shutterstock.com

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About the Author

Megan is a writer at A-Z Animals where her primary focus is birds, felines, and sharks. She has been researching and writing about animals for four years, and she holds a Bachelor of Arts in English with minors in biology and professional and technical writing from Wingate University, which she earned in 2022. A resident of North Carolina, Megan is an avid birdwatcher that enjoys spending time with her cats and exploring local zoological parks with her husband.

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