I wear an 11 in most running shoes, etc. I bought a pair of Danner Mountain Lites 20 years ago in size 11D. After who knows how many miles, replaced them with a pair of 11Ds purchased from the net this Christmas. Fit hasn't changed in 20 years. Hope this helps? For what it's worth, I personally don't think you can buy a better boot than Danner. Plus, they're still made in America!!