Allosaurus vs T-Rex: Who Would Win in a Fight

Written by Kyle Glatz
Updated: March 5, 2023
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The Allosaurus and T-Rex are two of the most intriguing dinosaurs to ever walk the planet. The Allosaurus lived 163 million years ago until about 144 million years ago. The Tyrannosaurus Rex lived 83.6 million years ago until 66 million years ago. The chances are good that the two never crossed paths with each other. That doesn’t mean we can’t use available information to figure out who would win in a fight between Allosaurus vs T-Rex.

We are going to take the available data and compare the two and draw conclusions about who would win in a fight between these two large dinosaurs. Take a look at the breakdown of vital information and see what would have happened if these two crossed paths. 

Allosaurus vs. T-Rex: The Main Differences

Allosaurus vs T-Rex
The T-Rex is taller, heavier, longer, and has bigger teeth compared to Allosaurus.
SizeWeight: 3000-4400lbs
Height: 16.5ft
Length: 38ft-43ft
Weight: 11,000-15,000lbs
Height: 12-20ft
Length: 40ft
Speed and Movement Type-21-35 mph
-bipedal striding
-17 mph
-bipedal striding
Bite Power and Teeth-3,900N bite power
-28-39 teeth
– 2-4-inches long
-D-shaped teeth with serrated edges
35,000N bite power
– 50-60 D-shaped serrated teeth
– 12-inch teeth
Senses–  Could hear lower frequencies
– Potentially had good smelling
– Had limited binocular field of vision, perhaps as good as modern-day alligators.
– A very strong sense of smell
– High vision with very large eyes
– Great hearing
Defenses– High running speed
– Large size
– Massive size
– Running speed
Offensive Capabilities– Sharp teeth, powerful bite
– Three sharp, curved claws on each hand and foot, upwards of 7 inches.
– Bone-crushing bites
– Speed to chase down enemies  
Predatory Behavior– Was likely an ambush predator that would attack the throat of its prey.
– Latches with the mouth and claws at the enemy with hands and feet.
– Possibly a devastating predator that could kill smaller creatures with ease
– Potentially a scavenger

The Key 7 Factors in a Fight Between Allosaurus and T-Rex

How Long Were Dinosaurs on Earth

The Allosaurus vs T-Rex fight would be settled by size, speed, and offensive skills


Every fight between massive creatures comes down to a handful of factors. We have identified seven vital pieces of information that would help us determine which dinosaur has the edge in a fight.

Although we summed these up in the table above, this breakdown will grant new insight into which creature would win in a battle.

Physical Features


Dinosaurs like the T-Rex were vast, powerful creatures


Size and strength matter in a physical fight between dinosaurs. Successful predators need to have a way to attack, harm and kill their opponent. They also need better senses and speed to gain the edge in a close match. Take a look at how these two measures up to one another. 

Allosaurus vs T-Rex: Size

Many dinosaur fights come down to size alone because the bigger one is just too much larger than the other. In this case, the T-Rex weighs up to 15,000lbs and stands at a height of about 20 feet with an average length of 40 feet. This dinosaur lives up to its name.

The Allosaurus is smaller on average, weighing just 4,000lbs and standing at 16.5 feet tall with a length that may have reached up to 43 feet. However, some cases had even bigger Allosauruses, like Big Al.

On average, though, a T-Rex is heavier, taller, and about as long, so they get the size advantage. 

Allosaurus vs T-Rex: Speed and Movement

In the wild, speed helps creatures land the first attack or get away from fights that they can’t win. Allosaurs were swift creatures, running at speeds up to 35mph. The T-Rex could only run at a max speed of 17mph.

The Allosaurus gets the speed advantage because it could run laps around the T-Rex.

Allosaurus vs T-Rex: Bite Power and Teeth

Many dinosaurs are believed to have killed their prey outright with their teeth or used it to finish off creatures wounded by other methods. The Allosaurus had almost 40 teeth that were each 2-4 inches long. They could bite down with 6,125lbf. That’s a massive bite.

The T-Rex had a bigger jaw, up to 60 teeth that reached 12 inches in length, with 8 inches of that tooth above the gums and available for biting. Their biting power was an unbelievable 17,000lbf.

The T-Rex has the advantage in terms of biting power and teeth.

Allosaurus vs T-Rex: Senses

A dinosaur’s senses could help it detect predators before they’re attacked or keep them out of an enemy’s line of sight. The Allosaurus did not have great senses. Its vision may be comparable to an alligator, its hearing was best suited for low frequencies, and it had the potential to detect many scents. However, its brain was too small to make use of the sensory data for the latter.

The T-Rex had a well-developed brain that made it smarter and more cunning than most dinosaurs. It had a great sense of vision owing to its orange-sized eyeballs. Its sense of smell was even more profound, capable of sniffing out prey and carrion.

The T-Rex gets the advantage in terms of senses. 

Allosaurus vs T-Rex: Physical Defenses

Not all fights are decided by offensive abilities. Sometimes, an impenetrable defense can stop deadly predators and prolong a fight. The T-Rex was massive and stocky, and it could move at a quick clip. The Allosaurus was lighter and faster, but also leaner.

The mass of the T-Rex is so much greater than the Allosaurus, so it gets the edge for defenses. 

Combat Skills

Allosaurus vs T-Rex - T-Rex Battle

Tyrannosaurus Rex had an incredibly powerful bite force.

©Herschel Hoffmeyer/

Being big won’t stop predators from killing a dinosaur with the right tools. Take a look at how each of these dinosaurs’ combat skills measures up.

Allosaurus vs T-Rex: Offensive Capabilities

The allosaurus has an interesting combination of a strong bite, fairly big teeth, and long claws. They could do some serious damage by biting and clawing their way across a large predator, like a T-Rex.

The T-Rex uses one tool very well: its massive jaws and teeth that can deeply puncture prey and snap bones with ease.

In this case, the T-rex and Allosaurus get a tie; both have specialty tools that can inflict overwhelming damage to their prey.

Allosaurus vs T-Rex: Predatory Behaviors

The Allosaurus was likely an ambush predator that used its speed and power to overwhelm its enemies. The T-Rex sniffed out its prey and attacked them because it was overwhelmingly powerful and dangerous.

The Allosaurus could stop a fight before it begins, but the T-Rex could use its senses to locate an enemy waiting for them. T-Rex gets the advantage.

What Are Key Differences Between Allosaurus and T-Rex?

The Allosaurus is smaller, faster, and had longer arms than the T-Rex.

The T-Rex was larger, heavier, and stronger than an Allosaurus. The Allosaurus was far quicker, had longer arms, and used stealthy hunting methods to kill its foes. T-Rex was a stocky and thick dinosaur, but the Allosaurus was relatively lean.

Who Would Win in a Fight Between Allosaurus and T-Rex?

Crocodile Bite Force - Deinosuchus Attacking a Dinosaur

The T-Rex would win in a fight against an Allosaurus.


A T-Rex would win in an Allosaurus vs T-Rex fight. The Allosaurus was a powerful creature in its own right, but the T-Rex was simply overwhelming in its power and size. Let’s consider how this fight would go down in the wild in two cases.

First, the best case for the Allosaurus would feature it ambushing the larger creature, waiting for the T-Rex to get just close enough before dashing out of its cover and making a thrashing leap for the T-Rex. The Allosaurus would crash into the massive foe, using its teeth to anchor it to its side while clawing with its feet and arms.

The wounds would be significant, and the T-Rex would thrash around until the Allosaurus fell off. The T-Rex would be hurt, but not too injured to fight back. The Allosaurus would go in for attack after attack, dodging with its great speed and agility, but it only takes one bite for the T-Rex to do deep, internal damage that ends the Allosaurus.

Conversely, the second case would see the T-Rex using its amazing senses to find the Allosaurus lying in wait. The Allosaurus would charge once discovered, right into the waiting maw of the T-Rex that ends the fight in a back-breaking crunch.

The Allosaurus is strong and tough, but unless it managed to avoid the T-Rex entirely, a hard feat, it would not get to do fatal damage and end the fight decisively. The T-Rex’s victory could be pyrrhic, though. If it took enough damage, the bleeding and trauma would catch up to it, killing it or leaving it vulnerable to other predators.

The photo featured at the top of this post is © Herschel Hoffmeyer/

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About the Author

Kyle Glatz is a writer at A-Z-Animals where his primary focus is on geography and mammals. Kyle has been writing for researching and writing about animals and numerous other topics for 10 years, and he holds a Bachelor's Degree in English and Education from Rowan University. A resident of New Jersey, Kyle enjoys reading, writing, and playing video games.

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