I ordered the extra-large version. I guessed that the whole sock would be extra-large.  The toe to heel was definitely extra-large.  The heel to calf was not.  This is appropriate for a bigfoot with pipe cleaner legs. I guess it's back to the woods for this bigfoot. (In case you wondered, my calf measures 17" at the largest and my shoe size is 14W in a Merrill Moab shoe.)