International Hat Size Conversion
Our hat size calculator converts head circumference to US, UK, EU, and international hat sizes. Find your perfect fit for fitted caps, dress hats, winter hats, and headwear from any country.
How Hat Sizing Works
Hat sizes are based on head circumference, but different systems express this differently. US sizes use fractions (6 3/4, 7, 7 1/4, etc.), UK uses similar fractions, EU uses centimeters (54, 55, 56, etc.), and some systems use S/M/L/XL. One size fits all hats use adjustable features.
Hat Size Formula
Measure head circumference where the hat sits (usually mid-forehead and above ears), then convert using size charts. Add 1/8 inch or 0.5 cm for comfort.
Example:
Head circumference of 22.5 inches = US size 7 1/8 = EU size 57 = Medium/Large.
Common Use Cases
Real-world applications for this calculator
Buying Hats Online
Order fitted hats from international brands or specialty hat shops.
Vintage Shopping
Convert vintage hat sizes to modern equivalents.
Uniform/Military
Size hats for uniforms, military dress, or formal headwear.
Tips
- Measure at the end of the day when your head is at its largest.
- Hair volume affects fit - measure with your typical hairstyle.
- Consider hat material (wool vs straw) which affects stretch.
- Size up if you plan to wear your hat with hair up or voluminous styles.
Frequently Asked Questions
Where do I measure my head for hat sizing?
Measure around your head where the hat will sit, typically about 1/8 inch (finger width) above your ears and across the mid-forehead. Keep the tape level and snug but not tight.
Should a hat fit tightly?
A properly fitted hat should feel snug but not tight. It should stay on in a light breeze without feeling like it's squeezing your head. You should be able to fit one finger between the band and your head.
What is the average hat size for men and women?
The average adult male hat size is 7 1/8 to 7 3/8 (57-59 cm). The average adult female hat size is 7 to 7 1/8 (55-57 cm). However, sizes vary widely among individuals.
How do I convert US hat sizes to European?
US sizes (like 7, 7 1/4, 7 1/2) can be converted to EU centimeter sizes by multiplying by 8. For example, US 7 = 56 cm, US 7 1/4 = 58 cm, US 7 1/2 = 60 cm.
What if I'm between hat sizes?
Size up to the next size. You can use sizing tape or foam strips inside the band to make a slightly large hat fit better. It's easier to size down a large hat than stretch a small one.