What Is the Average Size of the Human Head?


Doctors and researchers use data concerning the size of the head and brain to develop new advancements in medicine. This information related to the size of the human head is also useful to other professionals around the world. These include the fashion industry, safety equipment designers, eyeglass manufacturers, and other such groups.

Through collected data and reports, it has been determined that the average human head measures 6-7 inches in width and 8-9 inches in length. The average circumference of the human head is 21-23 inches. There are several factors that determine the exact size of each individual’s head. These uncover some of them.


Studies conducted by the University of Cambridge and the University of Oxford found that men tend to have a larger head size than women. These studies were performed on both men and women between the ages of 18 and 59 years old. When comparing individuals at the same age level, the findings were that men tend to have brains that are 8-percent to 13-percent larger on average than women. This resulted in larger head circumferences. 

Brain Size

The size of the brain is a major factor that determines the overall size of the head. The brain is housed inside of the skull cavity. When a baby is born, the skull is not completely connected or hardened. Localized soft spots, which are covered with tough, fibrous membranes, are called fontanels and they allow the fetal head to pass through the birth canal. Delicate fontanels close over time as the skull forms to fit the growing brain, as brains that are larger in size require bigger cavities. This directly affects the circumference of the head at the age of maturity.


When you hear that the food you eat affects your brain development, you should know this is true. The nutrition a person experiences from the time they are in-utero to what they choose to consume as adults can play a part in the size of their brains.

Studies conducted in various parts of the world monitored the nutritional values on body and head development. The findings show that women who consumed healthier diets during pregnancy gave birth to babies with body and head sizes that were within a normal range. Locations where there was poorer nutrition saw babies of smaller proportions being born.

Birth Order (Multiple Baby Births)

When studying the head circumference of babies born as a result of multiple births (such as twins and triples), scientists found that the birth order plays a role in the size of the head. While children that are born first tend to weigh more on average, children of these multiple births born last tend to have a bigger head circumference. This is due to the spacing inside of the uterus and the position of the child. It also shows the effects of nutrition as it is received by the child in-utero. Whether the child is male or female will also have an affect on the size of the head at birth. This also impacts the rate at which the head will grow at the earliest stages of life, while male babies tend to have higher growth spurts early on.

Medical Conditions

There is a wide range of medical conditions that can affect the size of the human head from birth throughout the individual’s lifetime. Some of these conditions include:

  • Microcephaly
  • Macrocephaly
  • Cephalic Disorders
  • Russell Silver Syndrome
  • Down’s Syndrome