Crochet hook sizes

Compare metric, US and traditional UK crochet hook labels.

Metric diameter	Common US label	Traditional UK label
2.25 mm	B-1	13
2.75 mm	C-2	12
3.125 mm	D	11
3.25 mm	D-3	10
3.5 mm	E-4	9
3.75 mm	F-5	—
4 mm	G-6	8
4.5 mm	7	7
5 mm	H-8	6
5.5 mm	I-9	5
6 mm	J-10	4
6.5 mm	K-10½	3
8 mm	L-11	0
9 mm	M/N-13	00
10 mm	N/P-15	000
12 mm	—	—
15 mm	P/Q	—
16 mm	Q	—
19 mm	S	—
25 mm	T/U/X	—

Choose by millimeters

Millimeter diameter is the reliable reference because letter and number labels vary by manufacturer. Steel thread hooks use a different numbering system. Always use the pattern gauge and make a swatch.

Cross Stitch Creator conversion chart. Labels vary, so check the millimeter marking on the hook and the gauge required by your pattern.

Check crochet gauge