How Should Chelsea Boots Fit Your Calf?
The calf is just below the knee. Any boot that reaches that high is not a chelsea.
The chelsea is an ankle boot. It should fit relatively snugly all through the instep and just to the "break" of the ankle...above which it doesn't really matter.
I was worried about the same thing when I got my first pair of chelsea boots and realized the opening didn't conform to my leg and was pretty much just wide open. I just rolled with it after some googling and I never really noticed since. The fit in the actual foot part was always fine. I think that's how they just are supposed to be.
Or I've been wearing severely misfitted chelsea boots for years