I really recommend going to the store and getting fitted properly. Your Allen Edmonds shoe size vs usual shoe size may surprise you. The sizing guide online is only accurate when considering your heel to toe length, which may vary from your heel to ball-of-foot length. For example, on the size guide, my length is a 7.5, but the size that fits the ball of my foot is 8.5 D. If you plan on investing in a quality pair of shoes, it's worth the time to get sized and fitted properly by a professional. Edit: In the past, people have had success tracing their foot on paper and sending it to the shoebank for a size recommendation.