I wear 8.5-9 so i got the 39 and the fit is perfect. It is a narrow type birk but i think it makes my feet look slimmer. I wore them 2 days in a row now and are very comfortable, no need to break them in. My reservations are these: when i bought them, they arrived with these white paint looking marks on them. I haven't attempted to take the marks off yet. But being brand new, this is a little conserning& dissappinting given the price tag on these. Also, where the back strap fastens to the outside cork sole, i can see the glue..  this doesnt seem like usual birk standard and i question longevity due to this. I DO think these are genuine, the question here for me is wheather or not they were rejected birks with minor defects, sold here for full price birks... not sure.