"My daughter is excited about her supergirl costume! She is size 7 so I had to take a chance and order up or down. I ordered 4-6 and it fit perfectly. The only drawback is that the boot covers are a bit small so we will need to find shoes they can fit over. This seems to be a common issue in many other reviews for this costume. Other than that, this costume will make our little girl very happy this Halloween!"