Human Bite Force: How Strong Is It, in Newtons and PSI?
Human bite force is usually measured in newtons, with adult molar readings often a few hundred newtons; about 700 N is a commonly quoted average. PSI measures pressure, not force, so a bite cannot be given a meaningful PSI value unless the tooth contact area is specified.
How strong is a human bite?
Bite force is measured with a sensor placed between the teeth, which records the force of a maximum bite. Typical adult results for the molars are in the hundreds of newtons. A commonly quoted average is about 700 N, which is about 160 lbf. The front teeth (incisors) give much less, because they are further from the jaw joint, so the jaw muscles have less leverage there.
Bite force depends on jaw muscle size, jaw shape, age and how many teeth you have. These are typical ranges, and individual people vary a lot.
Is bite force measured in psi?
Not properly. Force is measured in newtons (N) or pounds-force (lbf). Pressure is force divided by area, measured in pascals (Pa) or pounds per square inch (psi). When a source says "a human bite is 160 psi", it usually means 160 lbf, and the area is left out. The pressure under a tooth is far larger than that figure suggests, because the force goes through a very small area.
How do you convert bite force to psi?
- Start with the force: 700 N.
- Choose the contact area. For the tip of one molar cusp, take about 1 cm², which is 0.0001 m².
- Pressure = force ÷ area = 700 ÷ 0.0001 = 7,000,000 Pa (7 MPa).
- Divide by 6,895 (1 psi = 6,895 Pa): 7,000,000 ÷ 6,895 ≈ 1,015 psi.
So the same bite is about 160 lbf as a force, but roughly 1,000 psi as a pressure over 1 cm². Halve the area and the pressure doubles. This is why sharp teeth cut and flat teeth crush.
How does a human bite compare with other animals?
Bite force changes enormously with body size and diet.
- Human: about 700 N at the molars.
- Saltwater crocodile: about 16,000 N (about 3,700 lbf), measured in a study of captive crocodiles and the strongest bite recorded for a living animal.
Crocodile teeth are cones that grip prey rather than chew it, so their huge force is used for holding and crushing. Human teeth are shaped for cutting (incisors), tearing (canines) and grinding (premolars and molars), so the force is applied through different shapes.
Common mistakes
- Treating psi as a force. psi is pressure. A bite "of 160 psi" without an area is not a complete measurement.
- Comparing numbers measured different ways. A bite sensor, a lab measurement and an estimate from muscle size can disagree by a lot.
- Thinking force is all that matters. Force and tooth shape do different jobs: the same force through a smaller area gives a higher pressure.
Frequently asked questions
How strong is the human bite force?
About 300 to 900 N at the molars, with 700 N (about 160 lbf) a common average for adults. The front teeth give far less.
What is the human bite force in psi?
There is no single psi figure, because pressure depends on contact area. A 700 N bite over 1 cm² is about 1,000 psi; over 0.5 cm² it is about 2,000 psi.
What is the strongest bite force of any animal?
The saltwater crocodile, measured at about 16,000 N (about 3,700 lbf).
Which teeth bite hardest?
The molars. They are closest to the jaw joint, where the muscles give the most leverage, and they have the widest, strongest crowns.
Try it yourself
Open Teeth and tap through the incisors, canines, premolars and molars to see which shapes cut and which crush. Compare their roots and crowns, then think about how the same bite force is spread over a narrow tip or a wide surface. For how force and pressure work in general, see Forces and Newton's Laws.
See it for yourself, in 3D and free.
Try it in the Teeth & Tooth Numbers