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Hat Size Converter

Hat size US fractional ↔ UK ↔ EU ↔ letter (XS-XXL). Head circumference in cm.

Updated April 2026
US
7
UK
6 7/8
EU (cm)
56
Letter
M
How to measure your head

Use a soft tape (or wrap a string and measure on a ruler). Place it about 1 cm above your ears and just above your brow — where a hat normally sits. Hold it level and snug, not tight. Measure twice and take the larger of the two.

USUKEU (cm)Letter
6 1/26 3/852XS
6 5/86 1/253XS
6 3/46 5/854S
6 7/86 3/455S
76 7/856M
7 1/8757M
7 1/47 1/858L
7 3/87 1/459XL
7 1/27 3/860XL
7 5/87 1/261XXL
7 3/47 5/862XXL
7 7/87 3/4633XL
87 7/8643XL

Between sizes? Wool felt hats stretch up to ~1 cm — size down. Straw hats don’t stretch — size up. Fitted caps (New Era 59FIFTY etc.) run true to US fractional sizes.

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What it does

US 7 fits a 56cm head — but is that S, M, or L? This maps all four systems with the string-and-ruler measurement technique.

Runs entirely in your browser — no upload, no account, no watermark. For more tools in this category see the full tools index.

Embed this tool on your siteShow snippet

Paste this snippet into any page. Loads on-demand (lazy), no tracking scripts, and sized to most dashboards. Replace the height to fit your layout.

<iframe src="https://freetoolarena.com/embed/hat-size-converter" width="100%" height="720" frameborder="0" loading="lazy" title="Hat Size Converter" style="border:1px solid #e2e8f0;border-radius:12px;max-width:720px;"></iframe>
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How to use it

  1. Measure head in cm.
  2. Or enter a size.
  3. Read all systems.

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