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.
Tips
- Measure over thin clothing with a soft tape held snug but not tight, and keep the tape level all the way round.
- Take each measurement twice; if you are between sizes, the larger size is usually the safer choice.
- Size charts vary by brand and country – check the maker’s own chart when it is available.
- For sewing projects, pre-wash fabric before cutting and buy 10% extra for shrinkage, pattern matching and mistakes.
Common mistakes to avoid
- Mixing inches and centimetres between the tape and the size chart.
- Forgetting seam and hem allowances when cutting fabric.
- Measuring an old, stretched garment instead of your body.
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 upFoot length from US shoe size: men (size + 22) ÷ 3, women (size + 21) ÷ 3Worked example
Inputs — Sizing: Men's; I know: US shoe size; US shoe size: 10; Foot length: 26.67 cm.
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.
What formula does the Sock Size Calculator use?
Sock size ≈ foot length in inches, rounded up.