Knitting Needle Sizes and Conversion Chart

Knitting needle sizes can be confusing. That’s because different countries have different ways of numbering their knitting needles.

While the US and the UK use the same metric sizes, their numbering systems run in opposite directions.

In the US, needle sizes start at 0 and increase to 50. However, in the UK, sizes start at 14 and go up to 000.

In Japan, knitting needles use different standard metric sizes, starting at 2.1 mm and going up to 25 mm.

Confused yet?

To help you decipher the world of knitting needle sizes, refer to the charts below!

Knitting Needle Sizes Chart for US and UK

This knitting needle size conversion chart compares knitting needles in the US and UK, with crochet hook sizes thrown in for good measure!

Metric (mm)	US Size	UK Size	Crochet
2.0 mm	0	14	–
2.25 mm	1	13	B
2.5 mm	1.5	–	–
2.75 mm	2	12	C
3.0 mm	2.5	11	–
3.25 mm	3	10	D
3.5 mm	4	–	E
3.75 mm	5	9	F
4.0 mm	6	8	G
4.5 mm	7	7	–
5.0 mm	8	6	H
5.5 mm	9	5	I
6.0 mm	10	4	J
6.5 mm	10.5	3	K
7.0 mm	–	2	–
7.5 mm	–	1	–
8.0 mm	11	0	L
9.0 mm	13	00	–
10.0 mm	15	000	–
12-12.75 mm	17	–	–
15-16 mm	19	–	–
19.0 mm	35	–	–
20.0 mm	36	–	–
25 mm	50	–	–

Japanese Needle Size Chart

Note that Japanese needles have a different metric size than US and UK needles.

Metric (mm)	JPN Size
2.1 mm	0
2.4 mm	1
2.7 mm	2
3.0 mm	3
3.3 mm	4
3.6 mm	5
3.9 mm	6
4.2 mm	7
4.5 mm	8
4.8 mm	9
5.1 mm	10
5.4 mm	11
5.7 mm	12
6 mm	13
6.3 mm	14
6.6 mm	15

What is My Knitting Needle Size?

If you have knitting needles from all over the world or of unknown origins, your best bet for identifying their size is by using a knitting gauge.

A knitting gauge is a small tool made of plastic, metal or wood. Like a slice of Swiss cheese, it has a bunch of variously sized holes all over it.

Unlike Swiss cheese, these holes are precisely sized for measuring knitting needles!

knitting needle sizes comparison chart — This is a standard plastic gauge for measuring knitting needle sizes.

This is how it works:

Take your mystery needle and poke it through a similarly-sized hole in the knitting gauge.

If the needle slides in smoothly and sits snugly in the hole, then you’ve just identified your needle size. Mystery solved!

A knitting gauge is super useful, and every knitter should have one in their toolbox.

Thankfully, there’s one to suit every knitter’s personality and needs, from animal lovers to those looking for plain utilitarian plastic. Below, some highly-rated favourites: