I normally purchase shoes in a 9W, but the last pair I ordered felt a bit too big and sloppy.  Ordered this pair in 8.5W and it fits fine. I loved my previous pair, but the cork on the straps of this pair seems to be wearing very quickly.  The sole of the sandal also stains very quickly, making the sandal look older and more worn out than I would have expected in such a short time.  However,  I have high arches, plantar fasciitus, and morton's nueroma, and the Vionics are the ONLY sandal I can wear comfortably.