How to Measure Your Hat Size
All you need is a soft tape measure (or a strip of string and a ruler) and one measurement: your head circumference.
Step by step
- Wrap the tape around the widest part of your head — about 1 cm above the ears and eyebrows, where a hat actually rests.
- Keep it level all the way around and snug, not tight.
- Read the number in centimetres (or inches). That's your head circumference.
- Convert it below — or use the formula.
US hat size = head circumference in inches ÷ π (≈ 3.14). Example: 22 in ÷ 3.14 ≈ size 7.
Hat size chart
| Head (cm) | Inches | US | EU | S–XXL |
|---|---|---|---|---|
| 53.3 | 21 | 6⅝ | 53 | S |
| 54 | 21.25 | 6¾ | 54 | S |
| 55 | 21.625 | 6⅞ | 55 | M |
| 56 | 22 | 7 | 56 | M |
| 57 | 22.375 | 7⅛ | 57 | L |
| 58 | 22.75 | 7¼ | 58 | L |
| 59 | 23.125 | 7⅜ | 59 | XL |
| 60 | 23.5 | 7½ | 60 | XL |
| 61 | 23.875 | 7⅝ | 61 | XXL |
| 62 | 24.25 | 7¾ | 62 | XXL |
FAQ
How do I measure my head for a hat?
Wrap a soft tape measure around the widest part of your head — about 1 cm (½ inch) above your ears and eyebrows, where a hat sits. Keep it level and snug but not tight. That number is your head circumference.
What is the hat size formula?
US hat size = head circumference in inches ÷ π (about 3.14). A 22-inch head ÷ 3.14 ≈ 7, so it's a size 7 hat.
Is a size 7 hat medium or large?
A size 7 (about 56 cm / 22 in) is generally a Medium. M usually covers ~55–56 cm, L ~57–58 cm.
What if I'm between hat sizes?
Size up — a slightly loose hat can be taken in with sizing tape, but a tight one can't be made bigger. Adjustable or stretch-fit hats also help.
US hat sizing is defined as head circumference (inches) ÷ π. General reference; brands and styles vary.