Hat Size Calculator
Head circumference → US/UK/EU hat size.
How to use Hat Size Calculator
- Measure your head circumference.
- Enter it to get your equivalent US, UK, and EU hat sizes.
About this tool
Hat Size Calculator is a single-purpose utility on instant.tw, a free toolbox of calculators, converters, generators, and quick lookups. Everything works in your browser — nothing is uploaded, nothing is stored on a server unless explicitly noted.
Category: Sizing & Fit. Browse more Sizing & Fit tools.