What is the average thickness of a human hair? It can vary tremendously depending on race, and continent (Africans' average hair thickness is higher than Europeans', for example). It also depends if you talk about body hair or head hair. Hair from a human head is normally between .04 and .25 millimeters, averaging normally .1. Body hair depends on gender and even within individuals of the same gender and race it can be very different from an individual to another. The Thickest Hair in the human body belongs to a man's moustache. Usually hair is not completely tubular. Moustache hair is like a strap. The thinner dimension is as thick as 0.2MM and the thicker dimension is as thick as 0.3 MM. These are usually the thickest hairs measured. Sometimes very short abnormally thick hair is where the root is damaged and needs to be removed.