Hat Size Converter
Convert head circumference into US hat size, UK hat size, and international letter size (XS-XXL) all at once.
US Hat Size
7.25
UK Hat Size
7.25
International Size
M
Circumference
58.0 cm / 22.83 in
How the Hat Size Converter Works
Measure your head circumference (wrap a soft tape measure around the widest part of your head, just above the ears and eyebrows) and enter it in centimeters or inches. The converter gives you your US hat size, UK hat size, and an international letter size (XS through XXL), all at once.
UK hat sizing uses the same numeric scale as US sizing in practice — a US 7¼ and a UK 7¼ describe the same head circumference, so both are shown as the same figure here. International letter sizes are based on standard published bands: roughly XS (53–54cm), S (55–56cm), M (57–58cm), L (59–60cm), XL (61–62cm), and XXL (63cm+), though exact bands can vary slightly by brand.
Example
A 58cm head circumference converts to about 22.83 inches, which divided by π gives a US/UK hat size of roughly 7¼, and falls in the "M" international letter size band.
Common Use Cases
- Finding your correct hat size before ordering online from a US, UK, or European retailer.
- Converting a hat size you know from one sizing system to another.
- Buying a hat as a gift when you only have the recipient's head circumference measurement.
FAQs
- How do I measure my head circumference accurately? Wrap a soft measuring tape around your head about 1–2cm above your eyebrows and ears, at the widest point, keeping the tape snug but not tight.
- Are US and UK hat sizes really the same number? In practical terms, yes — both traditionally use the same inches-based sizing scale (like 7, 7⅛, 7¼), so a given head circumference produces the same numeric size in each system. What differs more is letter-size bands used by different international brands.
- Why do letter sizes sometimes not match my numeric size exactly? Letter-size bands (XS–XXL) are approximate ranges set by each hat maker, so borderline measurements can round differently between brands. Use the numeric size for the most precise fit when available.