I really like clarks boots, I own a couple other pairs (one black & one brown).  I purchased these as a gift, and I was tempted to see how they'd fit, so I tired them on.  The size, 7.5M, fits as expected.  (kinda snug on me, as I'm an 8 wide), however, the calves portion of the boot was huge.  supersized!  I have moderately large calves, and I've come across boots that are way too tight in the calves.  these boots are big in the calves on me, which was a shocker!  there was room for me to put my entire hand/arm inside the boot with my leg inside.  if you have large calves and don't mind some extra room in the calves, these may work for you.  if you have small calves, even medium, these might be too big!