Hat Size Converter
Convert hat sizes between US, UK, and EU standards, or calculate your size from head circumference.
100% client-side · no upload
How to use
- Measure your head circumference with a soft tape measure at the widest part, just above your ears and eyebrows.
- Enter the measurement in centimetres and click Find Size.
- Your hat size in US, UK, and EU standards is shown instantly.
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Frequently Asked Questions
- Is the hat size converter free?
- Yes, completely free with no signup and no usage limits.
- Does my data leave my device?
- No. All conversions run in JavaScript inside your browser. Nothing is sent to any server.
- Does it work on mobile?
- Yes. The tool is mobile-first and works on iPhone Safari and Android Chrome.
- What is EU hat size?
- EU hat sizes are equal to the head circumference in centimetres. A head circumference of 57 cm = EU size 57. US and UK sizes use fractional inches (e.g. 7⅛), which correspond to the same physical head measurement.
- How do I measure my head for a hat?
- Wrap a soft tape measure around your head at the widest point — usually about 1 cm above your ears and 1–2 cm above your eyebrows. Note the measurement in centimetres and enter it above. If you're between sizes, round up for a more comfortable fit.
Last updated: By jarvisbox