Extra Wide Calf: 17 ½ to a 20” boot; Super Wide Calf: 18 to 21” boot; 9 Place to Shop for Wide Calf Boots Zulily. This sample sale and discount retailer offers sooo many options seasonally and at great deals too! Duo Boots. I just wrote about this Boot Brand- especially for over the knee options. DUO Boots delivers wide calf boots up to a.