Due to fragmentary remains, estimating the size of C. megalodon has been challenging. However, the scientific community acknowledges that C. megalodon was larger than the whale shark, Rhincodon typus. Scientists have focused their research upon two aspects of size: (1) total length (TL), and (2) body mass (BM).
In the 1990s, marine biologists (e.g., Patrick J. Schembri, and Staphon Papson) opined that C. megalodon may have approached a maximum of around 24 to 25 metres (79 to 82 ft) in total length (TL). The early total length (TL) estimation of C. megalodon is perhaps not far-fetched. However, Gottfried and colleagues (1996) proposed that C. megalodon could likely approach a maximum of 20.3 metres (67 ft) in total length (TL). Currently most experts agree this giant shark reached a total length (TL) of more than 16 metres (52 ft).
The first attempt to reconstruct the jaw of this shark was made by Professor Bashford Dean in 1909. From the dimensions of this jaw reconstruction, it was hypothesized that C. megalodon could have approached 30 metres (98 ft) in total length (TL), but in light of new fossil discoveries and advances in vertebrate sciences this jaw reconstruction is now considered to be inaccurate. Major reasons cited for this inaccuracy are (1) relatively poor knowledge of C. megalodon's dentition in Dean's time, and (2) inaccurate muscle structures. Experts suggest that a rectified version of C. megalodon's jaw model by Bashford Dean would be about seventy percent (70%) of its original size and would lead to a shark size consistent with modern findings. To resolve such errors, scientists, aided by new fossil discoveries of C. megalodon and improved knowledge of its closest living analogue's anatomy, introduced more quantitative methods for estimating its size based on the statistical relationships between the tooth sizes and body lengths in the great white shark.