Luckily I bought these at an outlet store where I could try them on. I usually wear Reebok size 9.  This shoe in size 9 was too tight so went up to 9.5.  Still a little bit snug but after breaking them in are quite comfortable.  I have a relatively narrow foot anyway.  If you have average or wide feet you might want to get a different style of Nike running shoe. For me I like them and they are comfortable for long walks.  So I am pleased with my purchase. They were only 39 dollars at the outlet store.  A little more on Amazon.