Just thought I'd give my two cents as to the sizing on these. I measure exactly a size 9 and have an average to slightly wider than average foot. I first got these in a 9.5 and they fit fine with light or mid weight smartwool socks. However, I wanted to wear these with my heavyweight smartwools as this will be my cold weather set-up. I found that Size 10 fits great with heavyweight socks and fine with the mid weights as long as I cinch the boot tightly. So, if you want a proper fit, go a half size up. If you want to wear a heavy sock or two layers of socks, go a full size.