What makes Allen Edmonds shoes so unique is the extensive range of sizes and widths we offer that make achieving a perfect fit much simpler. Each half size increases by approximately one-sixth of an inch and each full size increases by one-third of an inch. The widths of Allen Edmonds shoes range from AAA, the narrowest width, to EEE, the widest width, with a D width considered medium. Technically speaking, each width increases by approximately three-sixteenths of an inch in total girth. Protects heels and sole edges.