Needle Size Conversion

Knittingtips.net

14/04/2026

Needle Sizes

Needle Size Converter

Easily convert between mm, US, and UK needle sizes.

mm	US	UK
2	0	14
2.25	1	13
2.5	–	12
2.75	2	12
3	–	11
3.25	3	10
3.5	4	–
3.75	5	9
4	6	8
4.5	7	7
5	8	6
5.5	9	5
6	10	4
6.5	10½	3
7	–	2
7.5	–	1
8	11	0
9	13	00
10	15	000
12	17	–
15	19	–
19	35	–
25	50	–

Understanding knitting needles

It's easy to get confused when buying needles online or knitting from international patterns. While some regions use the logical metric system, many countries still hold on to traditional designations.

Material choice affects the result

Even if the size is the same, the choice of material (such as bamboo, wood, metal, or plastic) will affect how the yarn slides and thus your personal gauge. Use the conversion table as a starting point, but always remember to check your own gauge with a swatch.

What is the difference between US and UK needle sizes?

The US system uses increasing numbers (0, 1, 2...) for thicker needles, while the old British system (UK) used decreasing numbers. Fortunately, most systems today use the metric system in millimeters (mm).

Is 4mm the same as US 6?

Yes, a 4mm needle usually corresponds to US size 6. See our complete table for all other sizes.