I am a 6.5 in dress shoes so I will normally take a 7 in sneakers....7 were too fitted with these shoes and it caused a pain at the back of my heel. I decided to go 1/2 a size up to 7.5 and although there is no heel pain, and the shoes is bigger which is recommended for running....these hurt my big toe nails. It is a good shoe but obviously just not for me.