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 diameter	US Knitting Needle Number	Corresponding Crochet Hook Size
2.25 mm	1	B-1
2.75 mm	2	C-2
3.25 mm	3	D-3
3.5 mm	4	E-4
3.75 mm	5	F-5
4 mm	6	G-6 (Boye G-6 is 4.25mm)
4.5 mm	7	7
5 mm	8	H-8
5.5 mm	9	I-9
6 mm	10	J-10
6.5 mm	10.5	K-10.5
8 mm	11	L-11
9 mm	13	M/N-13
10 mm	15	N/P-15
12.75 mm	17	—
15 mm	19	P/Q
16 mm	—	Q
19 mm	35	S
25 mm	50	U

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 UK	Yarn Weight US	Yarn Weight Australia	Needle Size	Hook Size
1 ply	Lace	2 ply	1.25-3mm	0.75-3mm
2 ply	Fingering	3 ply	1.25-3.5mm	2-3.5mm
4 ply	Sport	5 ply	3.25-4mm	2-3.5mm
DK	Light Worsted	8 ply	4-5mm	3.5-4.5mm
Aran	Worsted	10 ply	4.5-6mm	5-6.5mm
Chunky	Bulky	12-14 ply	5-8mm	6.5-9mm
Super Chunky	Super Bulky	16 ply	8-12mm	9-14mm
Super Chunky	Jumbo	20 ply	12mm +	15mm+