Graft Calculation

There are between 180-200 hair roots per square centimetre in a normal scalp. The aim in hair transplantation is to achieve this number. If the hairless area is large, 40-50 % less than this number can be implanted. This is because baldness occurs when about 50% of hair volume is lost. If the loss is more than 50%, baldness can be clearly seen.

The reason why numbers are not clear in these calculations is that the structure of hair strands differs from person to person. Depending on hair structure the visibility of the skin underneath increases or decreases.

  • Thick hair is more advantageous than fine hair.

  • Curly hair is more advantageous than straight hair.

  • Light-coloured hair, for example, greying hair, is more advantageous than black hair.

According to the information above, a minimum of 100 hair roots and a maximum of 200 hair roots must be transplanted to one square centimetre in a completely hairless area. Additionally, it is important to know that the number of hair roots and the number of grafts are two different things. Based on the information above, there are on average 2 hair roots in grafts collected by the most commonly used 0.7-0.75 mm FUE needles (punch). Thus, for transplantation a minimum of 50 grafts and a maximum of 100 grafts are needed per square centimetre on average.

In the video below, you can see how the area with hair loss is calculated and you can also roughly calculate how many grafts you need with our graft calculation software.

Area and graft calculation in hair transplantation