As with any kind of cosmetic procedure, the final results of a hair transplant won’t be known until the work has begun – or even finished. With a hair transplant, the bald scalp is covered with donor hair taken from other parts of the scalp – these donor areas as known as grafts. A hair transplant is not a quick procedure, and it can take many thousands of hair transplants to get the right look.
As to exactly how many hair grafts will be needed for any one person, it’s almost impossible to tell before the procedure starts. Some people will have the procedure done, and then decide to go back for more ‘filling out’. Others may be happy with the first grafts and leave it at that. And the initial degree of hair loss is also an important factor. After all, the less hair you have to start with, the more you will need to have transplanted. 
Roughly, however, around 800 to 1500 grafts will be needed to fix a receding hairline. The next biggest part of the scalp is the front third – this could need up to 2500 grafts (the minimum for this area is around 2000). This is an important part of the scalp to get ‘fixed’ as it contains the frontal tuft, which is the part of the hair that gives the greatest appearance of density. 2500 to 3000 grafts is the average for the front half of the scalp, and 3000 to 4000 is the average for the front two thirds.
The crown is often a different matter, and may only require 800 to 1200 grafts. This area if often given fewer grafts as more will be needed in other areas of the scalp – the crown can ‘get away’ with looking as though the hair is thinning if there is no more donor hair to use, whereas other parts of the scalp cannot.