Still very unsure on these yet. I have low arches, usually wear 10.5.. I ordered 10.5.. very roomy and have to way over tighten them to get my foot to not constantly completely lift off the sole inside the shoe. After my 12 hour shift my feet hurt like all hell. Inserts made them better but even with dr scholls inserts these still felt very large.. will be returning for a half size smaller.. maybe that will help. Way too roomy inside. The anti static worked awesome though and I never get shocked anymore.