How Tall Was a T Rex?
Tyrannosaurus Rex, King of the tyrant lizards, as most people know was a carnivorous Dinosaur from the late Cretaceous period. It was huge, twice as heavy as an African elephant, with a 5 ft long head and up to 40 feet in length. However for all its impressiveness was it actually as tall as is made out. We take a look in this article at how tall was a T Rex
Tyrannosaurus Rex was between 12 and 13 feet (3.6 to 3.9 metres) when measured from the floor to the hips, however from floor to the top of its head T Rex could measure over 17 feet (5.1 metres) tall when standing upright. For comparison the tallest giraffe ever was 5.7 m (18 ft 8 in).
There are rules that apply when measure the height of dinosaurs, and to be clear most of the figures you hear about dinosaurs are, by their nature, best estimates. However even with these estimates of how tall T Rex were, there is a science behind them.
So we will look at how tall was a T Rex and help you understand how paleontologists measure dinosaurs as well as how tall a T rex was compared to animals living today, other dinosaurs and the tallest of all dinosaurs as well.
What is the Tallest T rex found?
Currently, and you can read more about this here in our how big was a T Rex article, the largest known Fossil of a T Rex is a competition between 2 fossil discoveries. One is called Scotty and one is called Sue. Both were huge dinosaurs and were about 13 feet tall at the hips, and 40 feet long. You can see more information about them in the table below and in the article linked above as well.
Sue currently has the edge when it comes to provable height and size as this fossil is more complete that Scotty, Sue is over 90% complete and Scotty is around 60-65%. Although from comparison it is thought that Scotty would have actually been bigger it is just not possible to prove conclusively yet.
So sue was thought to be at least 13 feet tall at the hips, and with her head raised probably over 17 feet tall, Scotty the T Rex was at least comparably as tall and likey heavier as well.
Table 1: Estimated Heights of Known T Rex Fossils.
Fossil and Name | T-Rex Estimated height | Length Estimate | Weight estimate | Notes |
| Sue | 13 Feet tall to hips. 15.5 – 17 feet tall to head | 12.4 metres (40.7 feet) | 8-14 tons – 17500 lbs -30,000lbs (18651 lbs) | Discovered in 1990 Sue is one of the largest fully grown Tyrannosaurus fossil ever discovered it is in the field Museum of Natural history in Chicago. |
| Trix | 12.5 feet to hips 15 feet + to Head | 13 metre. 42 feet | 6 tonnes fossil weight, 12500 lbs) | Also one of the largest known T-rex fossils, is in the Naturalis biodiversity center in Montana found in 2013 similar in size to Sue. |
| Scotty | 13 Feet tall to the hips. over 15-17 feet to head when upright. | 42 feet – 12-13 metres | almost 20,000 lbs – 9 tons | Scotty may be the largest known T-Rex ever found. It is in the T-rex discovery centre in Saskatchewan Found in 1991 |
How Tall Is a Fully Grown T. Rex?
We will take a look at how tall was a baby T Rex below first in some detail, but at birth it is currently thought that a T Rex was about 1 foot ( 30 cm) tall and about 3 feet (1 metre) long. similar in height, though longer, than a small dog.
it was dangerous being small in the late cretaceous and T Rex would manage to grow taller and heavier quickly in its first few years. Fossils of two tyrannosaurs have been discovered that were age 13 and 15 at their time of death. These teenage Tyrannosaurs were between 6-8 feet tall, and about 4.5 to 6 metres in length, weighing about 2200 lbs, (1000 kg)
A T Rex would be considered adult size when it reached about 20 years old so it 5-7 years these teenage t Rex would have been expected to more than double in height to 13 feet and in length to 40 feet. While their weight would have increased by a massive 16000 lbs (7000 Kg) in that time.
For a long time shorter smaller fossils of Dinosaurs like Nanotyrannus, were thought to be separate species of carnivorous dinosaurs, however recently these have been classified as juvenile versions of T rex during its infant and teenage years.
We have a Table below to help put how tall is a T Rex at different stages of its life into perspective.
| Life Stage Of T Rex | How Tall | How Heavy | How Long |
| Newborn to 1-2 Years old | Around 30 Cm | 3-8 kg | 3 feet long ( 1 Metre) |
| Teenage – 13 -15 years Old | 8-10 feet | ||
| Adult – 20 years old Plus | 13 feet at hips 15 plus feet to head | 40 feet plus (13 metres) |
How Tall Were T Rex Babies.
Although no Fossilized Eggs or Hatchlings of a T Rex have been found as of yet. It is thought that T Rex babies would have been about 3 feet long and about 1 (30cm) feet tall close after hatching. The size of a small dog. they grew fast and at age 11 would have been large enough to chomp down on smaller dinosaurs. It is thought that T Rex eggs would have been about 17 inches long.
However when only 1-2 feet tall they would have had a diet of insects and lizards and possibly scavenged from other kills or parent kills ( depending on the family insects of a T Rex)
They were considered adult when they left their teenage years so would have grown from around 1 feet to 8-9 feet feet high is about 12 years, and then added another 5 feet in 8 years and another 16,000 lbs in weight. That’s a lot of smaller dinosaurs to eat!
How Tall Was T Rex Compared to Modern Animals.
We have plenty of large carnivores and herbivores alive on Earth today, so we did a little research to see how tall they are when compared to a T-Rex. We have included some comparisons of the largest animals found today to see if they could measure up to the height of a T Rex, and also included length and weight to let you see the different between predators today and predators in the time of the dinosaurs.
| Animal | Height | Length | Weight |
| Tyrannosaurus Rex | 13-17 feet (hips and head) | 40 Feet (12 metres) Plus | 11-15,000 Lbs (5-7000 Kg) |
| Bengal tiger | 4 Feet (1.1 Metres) at shoulder | 9-10 feet (2.8 -3 Metres) | 220 -660 Lbs (100 to 300 Kg) |
| Polar Bear | 4.2 feet (1.3 Metres) at shoulder. 7.8 Feet (2.4 metres) on hind legs | 7.8 – 10 Feet (2.4 to 3 metres) | 1000 Lbs ( 450 kg) |
| Giraffe | 16 -19 feet ( 5-5.9 metres) | 16-19 feet (5-5.9 metres) | 4200 Lbs ( 1900 Kg) |
| African Elephant | 12 Feet (4 metres) to Shoulder | 30 Feet (9 Metres) | 12000 Lbs ( 5400 Kg) |
| Mammoth | 14.5 Feet (4.5 metres) to shoulder | 33 Feet (10 Metres) | 12-22000 Lbs ( 6-10,000 kg) |
As you can see in all ways the T Re was taller, heavier and longer than all large mammals living today.
- Only the Giraffe is taller, and then only 3 or so feet. We also are measuring the giraffe to its head not its hips or shoulders.
- The largest land carnivore, the Polar Bear only reaches 8 feet or so when standing, compared to a T Rex Height of 13 feet to the hips it was tiny!
- The Mammoth, which is now extinct, although much more recently than a T Rex was able to look a T Rex in the eye should it need to but despite being a massive animal it was still smaller in both length and weight to a T Rex.
Dinosaurs as Tall As a T- Rex.
There is no doubting that a T Rex was a tall dinosaur, especially for a theropod and a carnivore. However there were plenty of large dinosaurs just as tall, and even more much taller. We will take a look at dinosaurs taller than a T-rex in the next section, but there were both herbivore and carnivore dinosaurs that were a similar height to a T Rex which we will take a quick look at below.
So if we take the T-Rex height as up to 13 feet tall, based on measuring to the hips as it was most likely more horizontal in its posture than vertical, at least most of the time. Then there are some pretty famous dinosaurs that could have looked a T Rex in the eye. (though not gone toe to toe with it – if you know what we mean)
Herbivore Dinosaurs As Tall As A T Rex
We have a few examples below of Herbivore dinosaurs as tall as a T-Rex
Parasaurolophus was a crested dinosaur with a 5 feet long crest on its head. ( more on this here) Although it was about 9 feet tall at the hips it thought to a have a much more upright posture ( most of the time) and would have been about 15 feet tall when standing up. Similar to a T Rex in height.
Stegosaurus had huge Plates along its back which certainly helped its height measurements. It could be up to 13 to 14 feet tall when including these. However at the hips it measured about 9 feet tall. Its head was much lower to the ground though at about 3 feet. So the only thing level with a T Rex ( if they ever could meet) would be the plates on its back.
You might not expect to see a Sauropod on this list of dinosaurs as tall as a T-Rex. These long necked dinosaurs were almost universally taller! However, if we take the measurement to the hips an average sized Diplodocus was about as tall as a T Rex at 15 feet. Of course if it raised its head then there eis no competition as it could add another 15 feet to that instantly!
Carnivore Dinosaurs as Tall as T Rex
Allosaurus has about 25% less length than a T Rex but could still look it in the eyes if they were alive at the same time ( they were not) it is estimated to be up to 16.5 feet tall when standing, and was thought to have a much more upright posture than a T – Rex. However, other than how tall it was, it would be no match for the much heavier predator.
Giganotosaurus may (or may not) be the largest predator that ever walked the Earth even though it is said to be in the Jurassic World Dominion movie. It was comparable in size in almost all aspects including height. It may even have been a little shorter at the hips at 12 feet compared to a T-Rex height at 13 feet. Either way it is fortunate for both these two massive tall predators that they lived 50 million years apart and on different continents.
Carcharodontosaurus is another carnivorous dinosaur that was of a comparable size and height to T Rex, and is thought to be one of the four largest predators ever. It was about 4 metres tall at the hips which is a similar height to T Rex.
What Dinosaurs were Taller than a T Rex?
There were many dinosaurs taller than a t rex, however most of them were herbivores, The only carnivorous dinosaur that might be taller significantly than a T Rex was the Spinosaurus which is thought to be the longest as well as the tallest.
It was thought grow to 16.5 feet ( 5 metres) to the head / hips which would make it as tall if not a little taller than a T Rex, but with the sail along the back that height extends to 21 feet tall. (6.5 metres).
Therizinosaurus was a large theropod, but a herbivore, and matched the T Rex in height if not in overall size. This long clawed plant eater is thought to have measured 4-5 metres tall. with how tall a T Rex was this puts it at Eye to Eye and even even a little taller than the massive predator.
Tyrannosaurus Rex may have been tall but by no means was it the tallest dinosaur. The truly massive Sauropods held than title. Currently, though it changes a lot as new information is brought to light, one of the tallest, if not the tallest dinosaur is thought to be the Sauropisian.
This dinosaur, a member of the brachiosaur family, had longer front legs than most other long necked dinosaurs, which gave its HUGE long neck a boost. These could be up to 18 meters tall (60 Feet) thats is over 4 times as tall as a T Rex, and about 10 times taller than people!
Why do they measure dinosaur height to the hips?
Most, though not all, dinosaur height measurements are taken from the floor to the top of the hips. this is especially true of theropods. There are a few reasons for doing this which we highlight below.
- T Rex and other dinosaurs are thought to have kept their head lower to the ground for most of the time this would make the neck and hips higher.
- Fossils are rarely found complete, especially heads, hips are a more constant measuring point than estimating neck and head length when not available.
- The head position can change depending on dinosaur activity so is a less reliable measurement, this is why length is often used as that is not dependant on posture. Hip height is much more stable and was thought to offer a more accurate measurement.
- If T-Rex raised its head it would certainly be taller than the 13 feet top estimate, but it was thought to mainly move with its head lower or level with its hips.
- This way of measuring height it not unique to dinosaurs, horses for example are measured to the shoulder rather than the head as they move their head to graze. Similarly if they raise up on hind legs we don’t take that measurement even though it would be larger.
How to measure Dinosaur Height
Measuring the height of long extinct dinosaurs from sometimes limited fossils is a tricky business. Luckily, and reasonably accurately, paleontologists have a few ways to measure Trex and other dinosaur heights
- From Fossils: With a rate of about 1 dinosaur a week, new dinosaurs are being discovered and named, many of these share traits or a classified in families and groups of other dinosaurs. This allows a paleontologist to use information they know from other similar dinosaurs to estimate size including height.
- Full Fossils: Less often a full or almost complete skeleton is discovered of a dinosaur. With complete skeletons it is much easier to accurately measure the likely height of the dinosaur. With the height of the T Rex “Sue” for example. the skeleton is almost 90% complete and once reconstructed is is relatively easy to answer the question. how tall is a T Rex.
- Footprints: Working out how tall a T Rex is, or any dinosaur, from its footprints sounds like it is really guess work. However it is possible and is often used especially in classrooms. There is a great lesson plan here to try out with more information. .
We have a huge selection or articles to answer the common and some less common questions about the Tyrannosaurus Rex here on the site and to make it easier to access we have them in the table below.
Was being tall useful for T Rex for Hunting?
While being tall made a T Rex easier to spot, it also gave it a higher viewpoint to see prey or threats, it was also a sign of dominance when dealing with other T Rex in fights for food or mates. In the World of the dinosaurs “Might usually made Right” and being tall was more of an advantage than a drawback.
In the modern animal kingdom bears and other animals use their height if not for the actual act of hunting, but for raising their head to be able to smell the air away from the ground. T Rex is thought to have had an excellent sense of smell and raising both its eyes and its nose to smell cleaner air would have been a distinct advantage.
Conclusion
An Adult Tyrannosaurus Rex would be an Average of 12 to 13 feet tall when measured from the ground to its hips. With its head raised this height could reach up to 17 feet tall. The measurements are taken to the hips as it is is a more accurate indication of height and hips are much more fixed than head or neck height.
Tyrannosaurs rex was not born tall, and had to grow and survive for over 20 years before it reached these heights in adulthood. When born, as we highlighted it was thought to be about 3 feet long and around 1 ft ( 30 cm) tall, growing to 8-9 feet in its early teenage years.
It is at this point the T Rex seems to experience its growth spurt, just like in humans ,and those tricky teenage years were when a T-Rex could add 5 feet to its height and 14,000 to its weight!.
So it may not be the tallest of the dinosaurs, but given the choice of meeting a brachiosaurus or a T Rex I think I know which I would prefer!
References
- https://www.guinnessworldrecords.com/news/2020/7/say-high-to-forest-guinness-world-records-reveals-the-worlds-tallest-giraffe
- https://royalsaskmuseum.ca/pub/Educate/Student%20Resources/Earth%20Sciences/Fossil%20Candidates/trex_english.pdf
- https://www.reddit.com/r/Paleontology/comments/ltblyc/why_is_dinosaur_height_measured_at_the_hips/
- https://www.bbc.co.uk/teach/class-clips-video/science-physics-ks2-ks3-how-to-calculate-the-height-of-a-dinosaur-from-its-footprint
- https://igws.indiana.edu/outreach/additional/activities/DinoMeasurements.pdf
- https://www.wvgs.wvnet.edu/www/museum/museallosaurus.
- https://www.nationalgeographic.com/science/article/first-tyrannosaur-embryo-fossils-revealed
Hi, I am Roy Ford a General Studies and English Teacher who has taught all over the world. What started as a fossil collection became a great way to teach, motivate and inspire students of all ages and all over the world about dinosaurs and from that and children’s love of dinosaurs came the site dinosaur facts for kids, a resource for all ages.
