Reference · Updated June 2026
Hat size reference
Hat sizes are simply your head circumference. The chart below maps it to every common labelling system — US fractions, UK fractions, EU centimetres and S–XXL.
| Head (cm) | Head (in) | US | UK | EU | INTL |
|---|---|---|---|---|---|
| 54 | 21 1/4 | 6 3/4 | 6 5/8 | 54 | XS |
| 55 | 21 5/8 | 6 7/8 | 6 3/4 | 55 | S |
| 56 | 22 | 7 | 6 7/8 | 56 | S/M |
| 57 | 22 1/2 | 7 1/8 | 7 | 57 | M |
| 58 | 22 7/8 | 7 1/4 | 7 1/8 | 58 | M/L |
| 59 | 23 1/4 | 7 3/8 | 7 1/4 | 59 | L |
| 60 | 23 5/8 | 7 1/2 | 7 3/8 | 60 | L/XL |
| 61 | 24 | 7 5/8 | 7 1/2 | 61 | XL |
| 62 | 24 3/8 | 7 3/4 | 7 5/8 | 62 | XXL |
| 63 | 24 3/4 | 7 7/8 | 7 3/4 | 63 | XXL |
How to measure
Wrap a soft tape around your head about 1 cm above the ears and the eyebrows — where a hat naturally sits. Hold it snug, not tight, and read the number in centimetres.
US vs UK fractions
Both use eighth-of-an-inch increments but start from a different base. A US 7 1/4 is a UK 7 1/8 — a difference of one eighth across the entire chart.
EU is the head measurement
Continental European hat sizes simply state the head circumference in centimetres. EU 58 = 58 cm head circumference.
Between sizes
If you fall between two sizes, choose the larger and use a sizing tape inside the band for a precise fit. Going down a size when your head is between is rarely comfortable.