Wrap a cloth tape measure around the circumference of your doll's head just behind the ears and across the forehead. Measurement should be in inches.

Most wigs have a stretch type cap which provides flexibility in sizing. This stretch cap makes it easier to place the wig on the dolls head. EXAMPLE: If your measurement of the dolls head is 14 5/8" a wig size of 14-15 is correct. 

Measure your doll's foot from heel to toe. Add 5mm to the length of the bare foot to determine the correct size of the size.