The shape of the heel in a sock

Short answer: A properly knitted heel has a gusset that follows the angle of the foot. Without it the sock slides down inside the shoe and folds under the foot.

What a heel has to do

The foot bends at almost a right angle at the ankle. A sock that is just a straight tube has to stretch over that bend, and it is pulled downward with every step. A knitted heel has extra stitches exactly there.

How to see the difference

Lay the sock flat. If you can see a clear angle where the heel bulges out, the heel is shaped. If the sock is completely straight, it is not. See bamboo socks for men.

What it means in practice

A shaped heel stays put, does not roll down at the back and wears evenly. An unshaped heel gives a fold under the foot and a hole in the heel before long. See bamboo socks for women and bamboo trainer socks for women.

Frequently asked questions

Can you see it in a photo of a sock

Often yes. Look for an angle between the leg and the foot.

Why do ankle socks slip off

Either the heel shaping is missing or the sock is a size too big.

Does the heel wear out fastest

Yes, along with the toe. Those are the two places that meet the shoe hardest.