Hook Sizes & Yarn Weights

Two quick-reference charts to match your hook to your yarn. Metric (mm) is the most reliable size, because US letters and old UK numbers vary between brands.

Crochet hook sizes

Crochet hook size conversion: metric, US and old UK
Metric	US	Old UK
2.0 mm	–	14
2.25 mm	B-1	13
2.5 mm	–	12
2.75 mm	C-2	–
3.0 mm	–	11
3.25 mm	D-3	10
3.5 mm	E-4	9
3.75 mm	F-5	–
4.0 mm	G-6	8
4.5 mm	7	7
5.0 mm	H-8	6
5.5 mm	I-9	5
6.0 mm	J-10	4
6.5 mm	K-10½	3
7.0 mm	–	2
8.0 mm	L-11	0
9.0 mm	M/N-13	00
10.0 mm	N/P-15	000
15.0 mm	P/Q	–

A dash means there is no common equivalent in that system. Steel hooks for fine thread use a separate numbering.

Yarn weights

Based on the Craft Yarn Council's Standard Yarn Weight System. Gauge is single crochet stitches per 10 cm (4 in).

Yarn weight chart with UK and Australian names, gauge and hook sizes
#	Weight	Also called	UK / AU	Gauge	Hook	Good for
0	Lace	Fingering, 10-count crochet thread	1–2 ply	32–42 dc*	1.5–2.25 mm	Doilies, fine lace
1	Super Fine	Sock, fingering, baby	3–4 ply	21–32 sc	2.25–3.5 mm	Socks, shawls, fine baby items
2	Fine	Sport, baby	5 ply	16–20 sc	3.5–4.5 mm	Light garments, lace runners
3	Light	DK, light worsted	DK / 8 ply	12–17 sc	4.5–5.5 mm	Baby blankets, granny squares, garments
4	Medium	Worsted, afghan, Aran	Aran / 10 ply	11–14 sc	5.5–6.5 mm	Amigurumi*, hats, bags, throws
5	Bulky	Chunky, craft, rug	Chunky / 12 ply	8–11 sc	6.5–9 mm	Quick hats, pet sweaters, rugs
6	Super Bulky	Super bulky, roving	Super chunky / 14 ply	7–9 sc	9–15 mm	Chunky blankets, cushions
7	Jumbo	Jumbo, roving	–	6 or fewer	15 mm and up	Arm-crochet style throws

* Lace weight is usually measured in double crochet, because it is mostly used for open lace.
* For amigurumi, use a hook one or two sizes smaller than the chart so the stuffing does not show. See single crochet.