I actually have pretty narrow feet and after reading several reviews about going up a 1/2 size, I decided to go to my nearest Foot Locker just to try them on.  Good thing I did, because I definitely needed the half size. Shoes are SUPER comfortable but I would recommend ordering up! I did end up ordering from Amazon anyway because there's about a $13 price difference! I'm an under pronator, with a high arch and these feel great. Just the right amount of cushioning and the mesh top makes them really breathable. Color is really fun too...don't mind waking up and pulling these on!