The thickness of the average human skull depends on a number of factors, including gender. The average skull thickness for men is .25 inches, and the average for women is .28 inches.
Although women's skulls are thicker than men's on average, their skulls are smaller, with the average front-to-back measurement being 6.73 inches for women and 6.93 inches for men. Though skull thickness is thought to improve the outcome for anyone experiencing a head injury, skull shape is also believed to play a role in how well a person responds to trauma to the head. Another thing of note is that skulls thin with age.