How big was megalodon?
Bigger than a whale shark, maybe. The answer depends on which estimate you trust.
How this site works. Every fact is in our own words and linked to its source, beside it. Megalodon is known almost only from teeth, so many numbers are estimates. Where good sources disagree, we show each version in a “Sources differ” box.
Only estimates
Only estimates are possible, because nearly all megalodon fossils are teeth. NHM news, 2022
Body lengths are estimated from tooth size, using the link between tooth size and body size in great whites and other living relatives. Britannica
How long?
How long did it grow? Sources differ
- Older length estimates, based on tooth size, suggest a maximum of 15 to 18 metres. NHM
- Smithsonian Ocean says the largest were roughly 60 feet (about 18 m) long, perhaps up to 50 tons, the size and weight of a railway carriage. Smithsonian
- Britannica says grown-up megalodons averaged 13 to 14 metres, with the largest up to an estimated 24.3 metres. Britannica
- A 2025 study by 29 fossil shark experts found that megalodon may have grown up to 24.3 metres long. NHM
The 24.3 m figure is a possible maximum for the biggest individuals, not a typical size.
The 2025 paper itself says megalodon possibly reached about 24.3 m in length. Shimada et al. 2025
The 24.3 m figure comes from nearly complete and partial backbones found in Belgium and Denmark, compared with 170 kinds of living and extinct sharks to work out head and tail sizes. NHM
That is about four times longer than the largest recorded great white, and a few metres longer than the biggest whale shark, measured at 18.8 metres. NHM
It would make megalodon only a metre shorter than Hope, the blue whale skeleton hanging in the museum’s Hintze Hall. NHM
It calls megalodon roughly up to three times the length of a modern great white. Smithsonian
The whale shark is the largest living fish. Meet it on sharks.animals.im’s whale shark page.
Females, males and cold water
Smithsonian Ocean also says females were bigger on average, about 13 to 17 m, and males about 10 to 14 m. Smithsonian
A 2022 study found that megalodons living in cooler water tended to grow bigger than those in warmer water. NHM news, 2022
Its lead author said the common idea that megalodon reached 18 to 20 metres should apply mainly to populations in cooler seas. NHM news, 2022
How heavy?
How heavy? Sources differ
- A shark that size may have weighed about 94 tonnes and cruised at around 2.1 to 3.5 km an hour. Shimada et al. 2025
- Britannica gives adult weights from about 30 tonnes to more than 65 tonnes. Most great whites weigh 680 to 1,800 kg. Britannica
Smithsonian Ocean’s figure, perhaps up to 50 tons, is in the length box above.
Born big
How long were newborns? Sources differ
- Reading the growth bands in a backbone, the 2025 study estimated a size at birth of 3.6 to 3.9 metres. Shimada et al. 2025
- The Natural History Museum puts it simply: newborn megalodons may have been up to 3.9 metres long. NHM
- Britannica, using young sharks’ teeth, says newborns may have been at least 2 metres long. Britannica
Jaws and bite
Its jaws are estimated to have opened 2.7 by 3.4 metres: big enough to swallow two adults side by side, or a London taxi. NHM
Britannica gives its bite diameter as 3 metres, several times that of an average great white. Britannica
Museum jaws are often shown opened wider than the living shark could manage, so that the teeth show. Smithsonian
How hard could it bite? Sources differ
- A human bite has been measured at around 1,317 newtons and a great white’s predicted at 18,216 N. Megalodon’s is estimated at 108,514 to 182,201 N. NHM
- Smithsonian Ocean says a megalodon bite could have reached about 40,000 pounds of force, which would be the strongest bite in the whole animal kingdom. Smithsonian
Our arithmetic: 40,000 pounds-force is about 178,000 newtons, inside the museum’s range.
Our view: even the smallest estimates make megalodon a giant. Whether it was 15 m or 24 m, it was far bigger than any predatory shark alive today.