I have crown balding and the area is like a circle 4 inches in diameter. I have no loss in the front (Photo)

The crown often takes more hair than other areas of a similar size because the swirl is present in the crown and the hair changes direction. The swirl draws the eye to the scalp. A 4-inch area will take anywhere between 2000-3000 grafts depending upon the thickness of your hair shafts. More coarse hair, the less is the grafts that are needed when compared to fine hair.