Shop Average wigs for women. Generally most wig styles are made in average cap head size measuring 21 - 22 total inches around the inside perimeter of the cap. Something else to note, most wigs also provide adjusters at the base of nape, which will allow some flexibility in slightly loosening or tightening the tension level by approximately one half inch. We carry a huge selection by the top name brands in average cap sizes, in varying hair lengths, textures, fibers in smoldering colors and shades from the traditional tones, highlighted, rooted, LR (long rooted,) Ombre, Gradient, and chunk highights. If you need help determining your head size measurement for accuracy ahead of time , CLICK HERE on our link : "HOW TO MEASURE YOUR HEAD SIZE FOR WIGS" for easy instructions on measuring.