"We got the Tin Man costume for my 8 y/o and the medium (8-10) just fits. They run a bit small. It is very cute, but the hat must have been made for a newborn. I am not sure it would even fit over the newborns head. I don't know what that is about, but still like the costume. We will have to make adjustments on the hat, but it will be darling with his lil sis as Dorothy."