The notorious jaws of the white shark Carcharodon carcharias are widely feared, yet poorly understood. Neither its bite force, nor how such force might be delivered using relatively elastic cartilaginous jaws, have been quantified or described. We have digitally reconstructed the jaws of a white shark to estimate maximum bite force and examine relationships among their three-dimensional geometry, material properties and function. We predict that bite force in large white sharks may exceed c. 1.8 tonnes, the highest known for any living species, and suggest that forces may have been an order of magnitude greater still in the gigantic fossil species Carcharodon megalodon. However, jaw adductor-generated force in Carcharodon appears unremarkable when the predator's body mass is considered. Although the shark's cartilaginous jaws undergo considerably greater deformation than would jaws constructed of bone, effective bite force is not greatly diminished.