List of Standard Crochet Hook Sizes

List of Standard Crochet Hook Sizes

The Craft Yarn Council of America (CYCA), an industry trade association, has collated a table of crochet hook 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 crochet hooks. The size of a crochet hook is determined by the diameter of its shaft.

Standard knitting needle and crochet hook sizes

Metric diameterUS Knitting Needle NumberCorresponding Crochet Hook Size
2.25 mm1B-1
2.75 mm2C-2
3.25 mm3D-3
3.5 mm4E-4
3.75 mm5F-5
4 mm6G-6 (Boye G-6 is 4.25mm)
4.5 mm77
5 mm8H-8
5.5 mm9I-9
6 mm10J-10
6.5 mm10.5K-10.5
8 mm11L-11
9 mm13M/N-13
10 mm15N/P-15
12.75 mm17
15 mm19P/Q
16 mmQ
19 mm35S
25 mm50U

The Complete Guide to using the right sized Knitting Needles or Crochet Hook with the right Weight Yarn

f you like to be a little creative with projects it helps to know what weight yarns equal to what plys and what crochet hooks can be used with what, so I have created this handy chart to help you chose the right fit every time.

So, whether you comparing English yarn terms to American terms or are looking for a guide on what crochet hook size is suitable for a 4-ply yarn, simply refer to the table below. 

Please note, this table has been created as a guide, always refer to the pattern or yarn in question. I would also recommend testing gauge and tension with a tension swatch.

Yarn Weight UKYarn Weight USYarn Weight AustraliaNeedle SizeHook Size
1 plyLace2 ply1.25-3mm0.75-3mm
2 plyFingering3 ply1.25-3.5mm2-3.5mm
4 plySport5 ply3.25-4mm2-3.5mm
DKLight Worsted8 ply4-5mm3.5-4.5mm
AranWorsted10 ply4.5-6mm5-6.5mm
ChunkyBulky12-14 ply5-8mm6.5-9mm
Super ChunkySuper Bulky16 ply8-12mm 9-14mm
Super Chunky Jumbo20 ply12mm +15mm+

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