Size Guide

Patterns and labels give sizes in millimeters, US letters or US numbers. Millimeters are the most reliable, so start there.

Crochet hooks

Millimeters	US size
2.25 mm	B-1
2.75 mm	C-2
3.25 mm	D-3
3.5 mm	E-4
3.75 mm	F-5
4 mm	G-6
4.5 mm	7
5 mm	H-8
5.5 mm	I-9
6 mm	J-10
6.5 mm	K-10½
8 mm	L-11
9 mm	M/N-13
10 mm	N/P-15
11.5 mm	P-16
15 mm	P/Q
19 mm	S
25 mm	T/U/X

Sizes such as 2.0, 2.5, 3.0, 7.0 and 12 mm have no standard US letter. Some makers print their own letters on those hooks, so go by the millimeter size. Shop crochet hooks

Knitting needles

Millimeters	US size
2 mm	0
2.25 mm	1
2.75 mm	2
3.25 mm	3
3.5 mm	4
3.75 mm	5
4 mm	6
4.5 mm	7
5 mm	8
5.5 mm	9
6 mm	10
6.5 mm	10½
8 mm	11
9 mm	13
10 mm	15
12.75 mm	17
15 mm	19
19 mm	35
25 mm	50

3.0 mm and 7.0 mm needles have no standard US number. Shop knitting needles

Which size fits which yarn

Yarn weight	Also called	Hook	Needles
1 Super Fine	Sock, fingering	2.25 to 3.5 mm (B-1 to E-4)	2.25 to 3.25 mm (US 1 to 3)
2 Fine	Sport	3.5 to 4.5 mm (E-4 to 7)	3.25 to 3.75 mm (US 3 to 5)
3 Light	DK, light worsted	4.5 to 5.5 mm (7 to I-9)	3.75 to 4.5 mm (US 5 to 7)
4 Medium	Worsted, afghan, aran	5.5 to 6.5 mm (I-9 to K-10½)	4.5 to 5.5 mm (US 7 to 9)
5 Bulky	Chunky, craft, rug	6.5 to 9 mm (K-10½ to M/N-13)	5.5 to 8 mm (US 9 to 11)
6 Super Bulky	Super bulky, roving	9 to 15 mm (M/N-13 to Q)	8 to 12.75 mm (US 11 to 17)
7 Jumbo	Jumbo, roving	15 mm and larger (Q and larger)	12.75 mm and larger (US 17 and larger)

These sizes and ranges come from the Craft Yarn Council standards, and they are starting points. A yarn listing or your pattern may suggest something different, and the gauge in your pattern comes first. Shop yarn