Crochet Hook and Knitting Needle Size Conversions

I recently ordered a couple of sets of 4" DPNs. I don't normally knit a lot of things that require little bitty DPNs, but I do knit a lot of Japanese patterns. A common stitch in these patterns is the wrapped stitch. You have to use a cable needle to do these. You knit across a certain number of stitches, then move them from the right-hand needle to a cable needle, wrap the working yarn around the stitches two or more times, then move them all back to the right-hand needle. It's cumbersome and slow, and I always feel particularly uncoordinated when I'm moving the stitches from the right-hand needle to the cable needle. I got the bright idea that I could knit the stitches to be wrapped directly onto the cable needle, so I don't need to move the stitches from the right-hand needle to the cable needle at all. Of course, that requires having a short needle of the right size.
Once I got the needles, I wanted to make a sort of case for them, because some of them came in little cellophane bags, and the others came in a case that's unnecessarily large and unwieldy. I made a sort of roll-up holder for my crochet hooks a long time ago and used a font stitch on my sewing machine to mark the sizes like this:

Here it is rolled up, in case you're curious:

I wanted to mark the sizes for my DPN case too. The sizes marked were a little strange, so I went off to the Internet to find a size conversion chart. I've done this many times in the past, and it's always a little frustrating. Some charts don't include all the sizes and sometimes there are discrepancies between charts. I also have trouble finding charts that have "the big four" (at least for me): metric, US, UK, and Japanese sizes. That set me off on a quest to put together a complete chart. I relied pretty heavily on Phretys' most excellent chart for the Japanese sizes, but I filled in a few sizes that weren't there. I compared many charts and then searched for actual needles and hooks for sale to verify the sizes. I found to my surprise that the larger crochet hooks vary in some significant ways among manufacturers. It's a good thing to know, although I generally shy away from heavy yarn.


Here's the result of my research. I hope it might be helpful. 

Note: ^†ミリ: Japanese jumbo sizes for knitting needles and crochet hooks are sized by mm

Knitting Needles					Crochet Hooks
Metric	US	UK	Japan*		Metric	US	UK	Japan
0.5	8/0	24			0.5			14
0.75	6/0	22			0.55			13
0.875		20			0.6	16		12
1.0	5/0	19			0.75	14		10
1.25	0000	16			0.85	13	7	9
1.5	000	15			0.9			8
1.75	00				0.95			7
2.0	0	14			1.0	12	6 ½	6 (1/0)
2.1			0		1.1	11	6
2.25	1	13			1.25			4
2.4			1		1.3	10	5 ½
2.5	1 ½				1.4	9	5
2.7			2		1.5	8	4 ½	2
2.75	2	12			1.65	7	4
3.0	2 ½	11	3		1.75			0
3.25	3	10			1.8	6	3 ½
3.3			4		1.9	5	3
3.5	4				2.0	steel  4	14 (steel 2 ½)	2/0
3.6			5		2.1	steel 3	steel 2
3.75	5	9			2.25	1/B (steel 2)	13 (steel 1 ½)
3.9			6		2.3			3/0
4.0	6	8			2.5		12	4/0
4.2			7		2.75	2/C (steel 1)	steel 1
4.5	7	7	8		3.0		11	5/0
4.8			9		3.25	3/D (steel 0)	10 (steel 0)
5.0	8	6			3.5	4/E (steel 00)	9	6/0
5.1			10		3.75	5/F
5.4			11		4.0	6	8	7/0
5.5	9	5			4.25	G
5.7			12		4.5	7	7	7.5/0
6.0	10	4	13		5.0	8/H	6	8/0
6.3			14		5.5	9/I	5
6.5	10 ½	3			6.0	10/J	4	10/0
6.6			15		6.5	10 ½/K	3
7		2	ミリ7†		7.0		2	ミリ7
7.5		1			8.0	11/L	0	ミリ8
8.0	11	0	ミリ8		9.0	15/N	00	ミリ9
9.0	13	00	ミリ9		10.0	16/P	000	ミリ10
10.0	15	000	ミリ10		15.0			ミリ15
11.0	17				15.75	Q
12.0			ミリ12		16.0	Q
15.0			ミリ15		19.0	S
16.0	19				20.0			ミリ20
19.0	35				Notes: The larger sizes vary by brand, with some sizes only available from certain makers. Sizes in the table are from Boye. Differences are noted below: Susan Bates: L 8.0, M 9.0, N 10.0, P 11.5 Lion Brand: 13/N 9.0, 15/P 10.0, 19/Q 15.75
20.0			ミリ20
25.0	50		ミリ25
30.0			ミリ30
*Japanese sizes also apply to Tunisian crochet hooks