List of United States standard crochet hook and knitting needle sizes - wikipedia List of 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. 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, 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. Standard knitting needle and crochet hook sizes Metric diameter US Knitting Needle Number Corresponding Crochet Hook Size 7000225000000000000 ♠ 2.25 mm 7000100000000000000 ♠ 1 B - 1 7000275000000000000 ♠ 2.75 mm 7000200000000000000 ♠ 2 C - 2 7000325000000000000 ♠ 3.25 mm 7000300000000000000 ♠ 3 D - 3 7000350000000000000 ♠ 3.5 mm 7000400000000000000 ♠ 4 E-4 7000375000000000000 ♠ 3.75 mm 7000500000000000000 ♠ 5 F - 5 7000400000000000000 ♠ 4 mm 7000600000000000000 ♠ 6 G - 6 7000450000000000000 ♠ 4.5 mm 7000700000000000000 ♠ 7 7 7000500000000000000 ♠ 5 mm 7000800000000000000 ♠ 8 H - 8 7000550000000000000 ♠ 5.5 mm 7000900000000000000 ♠ 9 I - 9 7000600000000000000 ♠ 6 mm 7001100000000000000 ♠ 10 J - 10 7000650000000000000 ♠ 6.5 mm 7001105000000000000 ♠ 10.5 K - 10.5 7000800000000000000 ♠ 8 mm 7001110000000000000 ♠ 11 L - 11 7000900000000000000 ♠ 9 mm 7001130000000000000 ♠ 13 M / N - 13 7001100000000000000 ♠ 10 mm 7001150000000000000 ♠ 15 N / P - 15 7001127500000000000 ♠ 12.75 mm 7001170000000000000 ♠ 17 -- 7001150000000000000 ♠ 15 mm 7001190000000000000 ♠ 19 P / Q 7001160000000000000 ♠ 16 mm -- Q 7001190000000000000 ♠ 19 mm 7001350000000000000 ♠ 35 7001250000000000000 ♠ 25 mm 7001500000000000000 ♠ 50 U References Jump up ^ Janine Flew, Diana Crossing ( 2006 ). Knit. Murdoch Books. pp. 10 -- 11. ISBN 978 - 1 - 74045 - 759 - 0. Retrieved 2008 - 10 - 11. Jump up ^ `` Hooks & Needles ''. Craft Yarn Council of America. Retrieved 2018 - 08 - 14. Jump up ^ Debbie Stoller ( 2006 ). Stitch ' N Bitch Crochet : The Happy Hooker. Workman Publishing. pp. 13 -- 15. access - date = requires url = ( help ) External links Wikimedia Commons has media related to Crochet hooks. Craft Yarn Council of America Retrieved from `` https://en.wikipedia.org/w/index.php?title=List_of_United_States_standard_crochet_hook_and_knitting_needle_sizes&oldid=854966722 '' Categories : Crochet Mechanical standards Standards of the United States Hidden categories : Pages using citations with accessdate and no URL Commons category without a link on Wikidata Talk About Wikipedia Add links This page was last edited on 15 August 2018, at 00 : 39 ( UTC ). Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: what letter is a size 4 crochet hook
Answer: E-4