Hat size conversion chart
Hat sizes are your head circumference in inches divided by π. Measure around the head just above the ears and eyebrows, keeping the tape level, then read across. When between sizes, most caps adjust; helmets should round up.
| Head circumference (cm) | Inches | US hat size | Letter size |
|---|---|---|---|
| 53 | 20¾ | 6⅝ | XS |
| 54 | 21¼ | 6¾ | S |
| 55 | 21⅝ | 6⅞ | S |
| 56 | 22 | 7 | M |
| 57 | 22⅜ | 7⅛ | M |
| 58 | 22¾ | 7¼ | L |
| 59 | 23¼ | 7⅜ | L |
| 60 | 23⅝ | 7½ | XL |
| 61 | 24 | 7⅝ | XL |
| 62 | 24½ | 7¾ | XXL |
| 63 | 24⅞ | 7⅞ | XXL |
Notes
- US hat size = circumference in inches ÷ π (3.14159).
- Hair volume and hairstyle can shift a size — measure with your usual hairstyle.
- For helmets, prioritize the manufacturer's own sizing; letter sizes differ between brands.
Frequently asked questions
- How do I measure my hat size?
- Wrap a soft tape around your head just above the ears and eyebrows, keep it level, and note the circumference in cm or inches.
- What hat size is 58 cm?
- 58 cm is 22¾ inches, which is US size 7¼ — a letter size L in most brands.
- Are hat sizes the same for men and women?
- Yes, the scale is unisex; women's average head circumference is slightly smaller (about 55 cm vs 58 cm).