Why 40 to 45 covers five shoe sizes
Short answer: The stretch in the sock makes the difference. A leg that can stretch by a third easily covers five steps in shoe size, and the foot adapts in the same way. That is why one pair can fit several feet.
The stretch makes the difference
A sock is knitted with elastic in the yarn, so it can stretch around a long foot and draw in around a short one. A leg that can stretch by a third easily covers five shoe size steps. That is exactly why a single pair can fit several feet.
What is actually measured
Sock size is based on the length of the foot, not the inside measure of the shoe. A range therefore describes a length with room at both ends, so the shortest and the longest foot in the range can both wear the sock. The middle sits between the extremes, and that is where the fit is most even.
The material does the work
With elastane in the yarn, the sock can draw in around a short foot and stretch around a long one. Without elastane the range would be much narrower, because yarn without elastic gives little. The material matters as much as the number on the label. See all bamboo socks for men.
Why five steps and not two
Five steps sounds like a lot, yet it is a difference in foot length that the knit can absorb. Production also gets simpler with fewer sizes, and a sock that fits several feet is easier to keep in stock. So many makers group several shoe sizes in one range.
How to find your range
Measure your foot from heel to longest toe and find the range the number falls in. If you have no tape measure, use the size of the shoes you wear most. In the middle of a range the sock fits best. At the edge, try the next range if it feels loose or tight.
The limit of what works
At the bottom of a range there is more fabric than the foot needs. It can fold under the foot and press. At the top the fabric is almost fully stretched, and the toe may feel it. A range works best when the foot sits somewhere between. See bamboo petticoat and all bamboo socks for women.
Ranges differ between brands
Ranges are not the same at every brand. Some use four steps, others six, and the feet are spread differently. A sock from one brand marked forty to forty five can therefore fit differently from one at another brand with the same numbers. Always read the range on the individual item.
Narrow or wide range
A narrow range is often better, because the sock then sits closer to the right length. In return it covers fewer feet, so more sizes are needed. A wide range is simpler to buy, but the fit depends a little more on where in the range your foot lies.
Care that keeps the shape
Socks can shrink a little in the wash, and you feel it most at the top of a range. Wash as the care label says and avoid high heat so the sock keeps its shape. If a sock still feels tight, the next range may suit your foot better.
Frequently asked questions
How do I find my range
Measure your foot from heel to longest toe and find the range the number falls in. If you are on the border, choose by whether you prefer a snugger or a looser sock.
Are ranges the same at every brand
No. Some use four steps, others six, and the feet are spread differently. Always read the range on the individual item, and do not assume a number means the same at two brands.
Is a narrow range better
Often yes, because the sock then sits closer to the right length. In return more sizes are needed, so it is a trade-off between fit and a simple choice of sizes.
You can find the full range at Bamboo-Clothing.com.
