US sock sizes are based on foot length in inches, so a sock size 11 fits a foot about 10–11 in long. Packs are often sold as S, M, L or as a range of shoe sizes. Stretchy socks cover a range of about two sock sizes.
How to use the Sock Size Calculator
- Sizing
- I know
- US shoe size
- Foot length
Results update as you type, and every field accepts the units shown in its menu.
How it works
Choose men’s, women’s or children’s sizing and enter your US shoe size, or choose to enter foot length.
Inputs explained
| Field | What to enter |
|---|---|
| Sizing | Choose one: Men’s, Women’s |
| I know | Choose one: US shoe size, Foot length |
| US shoe size | A number |
| Foot length | Units: cm, in, mm, m |
What each result means
- US sock size = ceil([Foot length (in)] – 0.000001)
- Foot length (cm) = [Foot length (in)]×2.54
Example values
How the main result changes when US shoe size changes and everything else stays at the example values above:
| US shoe size | US sock size |
|---|---|
| 5 | 9 |
| 7.5 | 10 |
| 10 | 11 |
| 12.5 | 12 |
| 15 | 13 |
| 20 | 14 |
Formula
Sock size ≈ foot length in inches, rounded up
Foot length from US shoe size: men (size + 22) ÷ 3, women (size + 21) ÷ 3
Worked example
Inputs: Sizing: Men's; I know: US shoe size; US shoe size: 10.
Results: Foot length (in) = 10.67; US sock size = 11; General size = M; Foot length (cm) = 27.1.
Frequently asked questions
What sock size for a size 10 shoe?
Men's US 10 shoe ≈ sock size 11 (medium–large).
Is sock size the same as shoe size?
No, sock sizes are usually 1–2 numbers higher than US men's shoe sizes.
What does "sock size 10–13" mean?
The sock fits feet about 10–13 in long, roughly men's shoe sizes 8–12.