Editing Crochet hook (section)

==United States standard crochet hook and knitting needle sizes==
Accurate [[knitting needle]] and crochet hook sizing is important for both crafts. There are, however, no uniform procedures for indicating these measurements.<ref name=flewcrossing>{{cite book|url=https://books.google.com/books?id=Ulv2kkxV2KYC&pg=PA10&dq=knitting+needle+sizes&ei=V97wSLvoF5KQzQSCqrngCg&sig=ACfU3U1cQlQKI9KTr-hrrRtHc9HatO6sZg#PPA11,M1|accessdate=2008-10-11|author=Janine Flew, Diana Crossing|title=Knit|publisher=Murdoch Books|year=2006|pages=10–11 | isbn=978-1-74045-759-0}}</ref>

The [[Craft Yarn Council of America]] (CYCA), an industry trade association, has collated a table of crochet hook and knitting needle sizes from ''de facto'' industrial standards and elicited the cooperation of its member organizations in adopting them to regularize sizing in the [[United States]]. The listed gauge systems are also widely used internationally. Their broader applicability is further highlighted by their normalization with the [[metric system]],<ref name="cyca">{{cite web|url=https://www.craftyarncouncil.com/standards/hooks-and-needles|title=Hooks & Needles|publisher=Craft Yarn Council of America|accessdate=2018-08-14}}</ref> which the CYCA members have agreed to have appear prominently on their packaging.

A [[hook gauge]] is used for measuring both knitting needles and crochet hooks. The size of a crochet hook is determined by the diameter of its shaft.<ref name=stoller>{{cite book |author=Debbie Stoller|title=Stitch 'N Bitch Crochet: The Happy Hooker|publisher=Workman Publishing|year=2006|pages=13–15}}</ref>  

Standard sizes are:
{|class="wikitable sortable" style="text-align: center;"
! Metric diameter
! US Knitting Needle Number 
! Corresponding Crochet Hook Size
|-
|align="center"| {{nts|2.25}} mm
| {{nts|1}}
|B-1
|-
|align="center"| {{nts|2.75}} mm
| {{nts|2}}
|C-2
|-
|align="center"| {{nts|3.25}} mm
| {{nts|3}}
|D-3
|-
|align="center"| {{nts|3.5}} mm
| {{nts|4}}
|E-4
|-
|align="center"| {{nts|3.75}} mm
| {{nts|5}}
|F-5
|-
|align="center"| {{nts|4}} mm
| {{nts|6}}
|G-6
|-
|align="center"| {{nts|4.5}} mm
|{{nts|7}}
| 7
|-
|align="center"| {{nts|5}} mm
|{{nts|8}}
|H-8
|-
|align="center"| {{nts|5.5}} mm
| {{nts|9}}
|I-9
|-
|align="center"| {{nts|6}} mm
| {{nts|10}}
|J-10
|-
|align="center"| {{nts|6.5}} mm
| {{nts|10.5}}
|K-10.5
|-
|align="center"| {{nts|8}} mm
| {{nts|11}}
|L-11
|-
|align="center"| {{nts|9}} mm
|{{nts|13}}
|M/N-13
|-
|align="center"| {{nts|10}} mm
|{{nts|15}}
|N/P-15
|-
| align="center" | {{nts|12.75}} mm
|{{nts|17}}
|—
|-
|align="center"| {{nts|15}} mm
|{{nts|19}}
|P/Q
|-
|align="center"| {{nts|16}} mm
| —
|Q
|-
|align="center"| {{nts|19}} mm
|{{nts|35}}
|S
|-
|align="center"| {{nts|25}} mm
|{{nts|50}}
|T/U/X
|}