I typically wear an 8 1/2 and ordered a 39, which seems to be the right size.  For reference, I have very average feet. The shoes are comfy other than the top on the outside--near the top middle part of  my outside toes, which rubs a bit, giving me a blister there.  I'm hoping that gets better after I wear them for a while.  The support feels great and so far they seem to be good quality.