If you use a Macro-lens on your cell phone (easily available on Amazon for under $30), you can take a look at your donor area and calculate your donor density and your total available grafts or hairs for hair transplants for your lifetime. I have counted the hairs in such a field for you. Each number reflects the hair count per follicular unit (or graft).
In this example, the total count is 140 hairs found in 56 Follicular units (or grafts) which means that this person averages 2.5 hairs/follicular unit (or graft). As the average Caucasian hair count is 2.2 hairs/follicular unit, this man has 20% more hair in his donor area than an average man. This will translate into more than 20% more grafts (logic will be presented another time). This means that this man probably has significantly more hair per graft which will translate into more donor grafts for his lifetime and a fuller hair transplant as each graft will have more hair. You need to do this calculation for your donor hair. If your donor area has 1.7. hairs per follicular unit (or graft) as shown in the second snapshot, then it would mean that your donor supply is not capable of producing a lot of grafts for treating an advanced balding pattern. These patients run the risk of a see-through donor area if they get FUE performed with any significant numbers, especially if they have a medium weight or fine hair.
The total number of Follicular Units on the entire hair baring scalp is 50,000 for an average head. To calculate the total number of hairs that you were born with and using Follicular Unit Density from the back of the head (permanent zone) just multiply the average number of hairs per follicular unit times 50,000 and that will give you a total birth hair count. Example, if your average donor density is 2.2 hairs/Follicular unit, then the total hairs on the hair baring scalp is 2.2 * 50,000 = 110,000 hairs (which happens to be the average hair count for a Caucasian Male). From that calculation, the surgeon can determine how many GRAFTS you have for hair transplants that can be donated during your lifetime. Usually, a comfortable number of transplantable grafts ranges from 1/3rd to 2/3rds of 12% of the 50,000 birth number of Follicular Units, a constant in most people. When a person has a coarser hair, the number of grafts that can be transplanted goes up for 12% and when the person has fine hair it goes down from the 12% number.
I will tell you that doctors opinions vary considerably on this 12% number of transplantable grafts. A competent doctor will put this into perspective for your Personalized Master Plan for your hair loss. Every balding man thinking that some day they may get a hair transplant must understand how to do this very simple calculation.
Low Donor density