Hat size chart
Your US fitted hat size is your head circumference in inches divided by pi, rounded up to the next eighth: a 22.5 in head is a 7 1/4. Measure once and get your size in every system.
Hat size chart: the tool
Find your hat size
Measure round the head about 1 cm (1/2 in) above the eyebrows and ears, where the hat sits. Keep the tape snug, not tight.
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How to measure
Fitted hat size chart and cap sizes by head circumference
| US size | Head (cm) | Head (in) | Letter size |
|---|---|---|---|
| 6 3/8 | 51 | 20.25 | XS |
| 6 1/2 | 52 | 20.625 | XS |
| 6 5/8 | 53 | 21 | XS |
| 6 3/4 | 54 | 21.5 | S |
| 6 7/8 | 55 | 21.875 | S |
| 7 | 56 | 22.25 | M |
| 7 1/8 | 57 | 22.625 | M |
| 7 1/4 | 58 | 23 | L |
| 7 3/8 | 59 | 23.375 | L |
| 7 1/2 | 60 | 23.75 | XL |
| 7 5/8 | 61 | 24 | XL |
| 7 3/4 | 62 | 24.5 | 2XL |
| 7 7/8 | 63 | 25 | 2XL |
| 8 | 64 | 25.5 | 3XL |
US, UK and EU hat sizes
| EU (cm) | US | UK | Head (in) |
|---|---|---|---|
| 53 | 6 5/8 | 6 1/2 | 20.5 |
| 54 | 6 3/4 | 6 5/8 | 21.25 |
| 55 | 6 7/8 | 6 3/4 | 21.5 |
| 56 | 7 | 6 7/8 | 22 |
| 57 | 7 1/8 | 7 | 22.5 |
| 58 | 7 1/4 | 7 1/8 | 22.875 |
| 59 | 7 3/8 | 7 1/4 | 23.25 |
| 60 | 7 1/2 | 7 3/8 | 23.625 |
| 61 | 7 5/8 | 7 1/2 | 24 |
| 62 | 7 3/4 | 7 5/8 | 24.5 |
| 63 | 7 7/8 | 7 3/4 | 24.875 |
| 64 | 8 | 7 7/8 | 25.25 |
| 65 | 8 1/8 | 8 | 25.625 |
Head size by age
| Age group | Inches | cm |
|---|---|---|
| Preemie | 9 to 12 | 23 to 30.5 |
| Baby | 14 to 16 | 35.5 to 40.5 |
| Toddler | 16 to 18 | 40.5 to 46 |
| Child | 18 to 20 | 45.5 to 51 |
| Tween | 20 to 22 | 51 to 56 |
| Woman | 21 to 23 | 53 to 58.5 |
| Man | 22 to 24 | 56 to 61 |
Why makers' inch columns differ
They disagree on the inch column by up to about 3/8 in: for US 7, Stetson says 22 1/4 in, Lock & Co 22 in, Stormy Kromer 21 7/8 in (7 x pi = 21.99). For a tool, compute from cm or from the pi formula rather than mixing these columns.
Related tools
Questions
How do I measure my head for a hat?
Wrap a soft tape round your head about 1 cm above the eyebrows and the tops of the ears. Read the number where the tape meets. Between sizes, go up.
What hat size is 22 1/2 inches?
22.5 in divided by pi is 7.16, so a US 7 1/4 if you round up to the next eighth, or 7 1/8 on charts that round to the nearest. 22.5 in is 57.15 cm.
What is a 7 1/4 hat size in cm?
About 58 cm. On the makers' charts each US eighth is one centimetre: 7 is 56 cm, 7 1/2 is 60 cm.
Is a UK hat size the same as US?
No. UK sizes are one eighth smaller: a US 7 1/4 is a UK 7 1/8.
Sources
- Stetson: Size Guide (checked 2026-10-02)
- Lock & Co. Hatters: Hat Size Chart & Measuring Guide (checked 2026-10-02)
- Stormy Kromer: Know Your Cap Size (checked 2026-10-02)
- Craft Yarn Council: Head Circumference Chart (checked 2026-10-02)
- Wikipedia: Hat (Size section) (checked 2026-10-02)
Last checked: 5 October 2026