I bought this socks for my daughter, she is 6 years old and her  shoe size is 10.5 and the 6-7 fit her fine. The socks do fit right under the knee and not as thick as I would like it to be. The socks is fine for fall, spring and states with nice weather year round. If you get cold winter's  like me on the east coast, it is not thick enough for that. All in all a ok buy, try it you might like it.