Cap Size is for Average size heads – 21.5″-22.5″. With a tape measure, begin at the front of your hairline and wrap the tape behind your ear to the nape of your neck around to your other ear until the tape meets again at the front of your hairline. 95% of the population will fit the average wig size A wonderful Troll style costume wig that stands up straight. This wig can pass for an Oompa Loompa from Willy Wonka movie Cat in the Hat Thing 1 or Thing 2 or a simple Troll character.