Hat size calculator
Enter your head circumference to find your hat size.
Hat size is determined by head circumference in centimetres. The French system uses this value directly: size 57 = 57 cm head circumference. The US and UK systems use the diameter in inches or fractions. Most unisex hats cover sizes 54 to 62 cm.
Measure your head at its widest point, about 1 cm above the eyebrows and ears. Hold the tape horizontal, snug but not tight. Measure twice to confirm. If you wear your hair up or in a bun, measure with the same hairstyle as when wearing the hat.
- Take a soft tape measure.
- Place it horizontally around your head, 1 cm above eyebrows and ears.
- Adjust snug but not loose.
- Note the measurement in centimetres: that is your FR size.
| Head circumference (cm) | FR size | US size | Letter size |
|---|---|---|---|
| 53 cm | 53 | 6 5/8 | XS |
| 54 cm | 54 | 6 3/4 | XS |
| 55 cm | 55 | 6 7/8 | S |
| 56 cm | 56 | 7 | S |
| 57 cm | 57 | 7 1/8 | M |
| 58 cm | 58 | 7 1/4 | M |
| 59 cm | 59 | 7 3/8 | L |
| 60 cm | 60 | 7 1/2 | XL |
| 61 cm | 61 | 7 5/8 | XL |
| 62 cm | 62 | 7 3/4 | XXL |
| 63 cm | 63 | 7 7/8 | XXL |
| 64 cm | 64 | 8 | XXXL |
| 65 cm | 65 | 8 1/8 | XXXL |
Frequently asked questions
What if I'm between two sizes?
For a wool or fleece hat, size up (the material stretches). For straw or rigid hats, take the nearest size. Many hats have an internal adjustment band.
Are women's and men's sizes different?
Average head circumference is larger for men (56-58 cm) than women (54-56 cm), but the measurement system is identical. Hats are sold by head circumference, regardless of gender.
How do I measure a child's hat size?
Same method (head circumference, 1 cm above eyebrows). Children's sizes typically range from 50 cm (3-4 years) to 56 cm (12-14 years). Baby hats are 38-46 cm.
What do XL and XXL correspond to?
XL is 60-61 cm, XXL is 62-63 cm, XXXL is 64-65 cm. Above that, custom hats are needed. Baseball caps often have adjustments covering several sizes.