I followed the keen website's advice to get a .5 size up, that they run small. But i found that they were just a half size to big. If you want the ball of your foot and the heel in the right place buy your size. They are fairly wide, and stretch a bit. My size (6) not 6.5 fits very comfortably. Had to return the first pair, but back country was great and very quick (even the free shipping) Love my shoes, wear them every day. Only problem, my feel seem to smell a bit, something about sandals make my feet smell. But, I can waer the shoes through the day, no feet problems.