The head circumference of a man of about 170cm height is generally up to 50 to 53 centimeters or more. The size of the human head circumference is mainly related to the age development changes, the newborn head circumference is about 34 centimeters, half a week after birth can grow to 42 centimeters, a week after birth can grow to 45 centimeters, two-year-old children head circumference can reach 47 centimeters. The head circumference of children aged three to four can reach 48.5 centimeters, and the head circumference of those aged four to ten can reach 50 centimeters, and from then on until adulthood after the age of 18, the head circumference of human beings can reach 53 centimeters or more, and will not undergo any further major changes.