mm to US crochet hook size
Type the size printed on your hook to see what it is called in American patterns.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter hook diameter.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
The diameter is looked up in the Craft Yarn Council hook chart; if there is no exact match, the closest size is shown.
Example
Inputs: Hook diameter = 5 mm. Result: US size: H-8; Diameter of that size: 5 mm; Exact match: Yes.
Limits and caveats
- The chart used does not list sizes such as 3 mm or 7 mm, so the nearest US size is shown for them.
- Steel lace hooks thinner than 2 mm are not covered.
Questions about this tool
What US size is a 5 mm crochet hook?
H-8.
What US size is a 6 mm hook?
J-10.
What US size is a 3.5 mm hook?
E-4.