How to Measure for a Wig Wrap tape around above the ears and across the forehead, all the way around to get the circumference of the head. All our wigs are on stretchy elastic bases and so are suitable for 2 sizes. If your head size falls in between the sizes that are available , then choose the smaller size. You can always snip the wig cap to ease the wig onto your doll. If the wig is too big then the doll will appear to have too much hair.