My Mk IIIs - 9-91/2 E, Altama Jungle Boots - 10W, Civie shoes - 10.5, Danner/Swat/5.11 - 11, WWB - 280/102, GP - 275/104. No set standard really - based on boot manufacturer. Needless to say, important to check with stock insoles as well as after-market (Superfeet, Custom Soles, Spencos etc) for...