Really depends on the shoes, and the way they're cut/made. Better quality shoes that are available in extra wide widths, I can wear a 10.5 or 11, but if they're not as widely built, I have to go for a larger size to get the width I need...which sucks, having shoes that are Ronald McDonald shoes just because I have wide "Flintstone Feet."
My workboots, which are hand made and custom fitted to my feet are 10.5 FF (4E) I have some Finn Comfort shoes that are about an 11 extra-wide and they fit very nicely. "Athletic shoes" are where I have the problem getting wide widths, which is why I only wear New Balance...one of the few that make widths wide enough for me.