Sock sizes and why they do not follow shoe size

Short answer: Socks are sold in ranges like 40 to 44, because the knit stretches. If you fall at the top of a range, choose the next size up, or the sock stretches flat and wears out faster.

The range covers several sizes at once

A range of four sizes works because the knit gives way and adapts to the foot. But at the top of the range, the sock is already stretched close to its limit, while at the bottom there is plenty of room left to give. See bamboo socks for men.

A stretched sock wears out faster at the heel

When the knit is pulled fully taut, the fabric grows thinner across the heel and toe, and wear sets in much faster than in a sock with more room to give. This first shows up as holes exactly where the shoe presses hardest.

Socks that are too big fold inside the shoe

If the sock is too big, it folds inside the shoe, and folds cause blisters on long walks or runs. A sock that is slightly too big feels soft at first but turns uncomfortable after a few hours. See bamboo socks for women for the right range.

The material changes how the range feels

Bamboo knit stretches differently from cotton, because the fibres are smoother and more elastic. This means the same range can feel looser in a bamboo knit than in pure cotton, even when the numbers on the pack are identical.

The toes are often the first to feel it

Before the heel, most people notice their toes being squeezed if the sock is too small. That happens because the toe area has less knit to give than the rest of the foot. When in doubt, always choose the size up.

Sport and everyday wear ask for different things

For running and training it matters that the sock sits snug without being tight, so it does not shift inside the shoe. For everyday wear a slightly looser range can feel more comfortable. See bamboo tennis socks for men for a style built for movement.

Washing can change the range over time

Knit can shrink slightly when washed at high temperature, even when it is machine washable. If you always wash cool and skip the tumble dryer, the sock keeps its original range far better across its whole lifetime.

Different brands use different ranges

A range of 40 to 44 at one brand is not necessarily the same at another. Trust mainly how the sock actually fits, and treat the numbers on the pack as guidance rather than a guarantee.

Choose by foot width, not just length

Two people with the same shoe size can have very different foot widths. A wide foot fills more of a range, and here it makes extra sense to choose the top number in the range so the sock does not press too hard.