I can just tell you my experience with my kids. DD5 measures an 11 and no longer needs wide, but did as a toddler. Her 10/11 Crocs are too short and she is very happy with the 12/13. I just ordered a pair for my DS2. He is wearing a 7.5 and I ordered the 8/9 because he still has a wide foot and I was hoping to get longer use out of them. Hope this helps!