I normally wear a 10.5 with Nike and had to go with size 12 for these. Adidas' tend to run small for me; I usually have to wear a size 11 or 11.5. This is the first time I had to go size 12. This is more to do with the width than anything else, as a size 11.5 was good on length but the width hurt my left foot. Luckily, size 12 is not too long, where the front of the shoe folds when I bend my foot/toes. Once I knew my size and got the shoes, they have been great! Very comfortable. I use them as a pair of casual shoes, walking around, day to day kind of stuff.