Go up a half size. I purchased these for my daughter who wears a women's 8 wide or 8 C width (Men's 6.5 medium) and they fit me perfectly (like a men's 6 narrow or B width).  I wear a women's 7.5 to 8 and I have a narrowish foot with a high instep. Instead of returning the shoes for a different size I kept them for myself and ordered a different pair for her. This is a significant thing to note because in my past experience; ADIDAS tends to have a large toe box compared to say, Reebok or Saucony, and I generally cannot wear them for running or working out (this includes the women's sizes), but these worked perfectly for me at the gym and for street running.  They are very comfortable and did not cause my normal shin splints.  So if you are a man with a narrow foot and a high arch; these are your jam.