Nominal diameter hole D (mm)		Pitch P (mm)		Flat size A/F (mm)			External diameter A/C (mm)	Height H (mm)
1st choice	2nd choice	coarse	fine	ISO	DIN	JIS		Hex Nut	Jam Nut	Nylon Nut
1		0.25		2.5
1.2		0.25
	1.4	0.3
1.6		0.35		3.2
	1.8	0.35
2		0.4		4				1.6	1.2	-
2.5		0.45		5				2	1.6	-
3		0.5		5.5			6.4	2.4	1.8	4
	3.5	0.6		6
4		0.7		7	7	7	8.1	3.2	2.2	5
5		0.8		8	8	8	9.2	4	2.7	5
6		1	0.75	10	10	10	11.5	5	3.2	6
	7	1			11			5.5	3.5	-
8		1.25	1	13	13	12	15	6.5	4	8
10		1.5	1.25 or 1	16	17	14	19.6	8	5	10
12		1.75	1.5 or 1.25	18	19	17	22.1	10	6	12
	14	2	1.5	21	22	19		11	7	14
16		2	1.5	24	24	22	27.7	13	8	16
	18	2.5	2 or 1.5		27			15	9	18.5
20		2.5	2 or 1.5	30	30		34.6	16	10	20
	22	2.5	2 or 1.5	32
24		3	2	36			41.6	19
	27	3	2	41
30		3.5	2	46			53.1	24
	33	3.5	2
36		4	3	55			63.5	29
	39	4	3
42		4.5	3
	45	4.5	3
48		5	3
	52	5	4
56		5.5	4
	60	5.5	4
64		6	4

Note that flat (wrench) sizes differ from industry standards. For example, wrench sizes of fastener used in Japanese built cars comply with JIS automotive standard.

Mechanical specifications of Metric/English sized nuts

Material	Proof strength	Tensile yield strength (min.)	Tensile ultimate strength (min.)	Nut marking	Nut class
ISO 898 (Metric)
Low or medium carbon steel	380 MPa (55 ksi)	420 MPa (61 ksi)	520 MPa (75 ksi)		5
Medium carbon steel Q&T	580 MPa (84 ksi)	640 MPa (93 ksi)	800 MPa (116 ksi)		8
Alloy steel Q&T	830 MPa (120 ksi)	940 MPa (136 ksi)	1040 MPa (151 ksi)		10
SAE J429 (English)
Low or medium carbon steel	55 ksi (379 MPa)	57 ksi (393 MPa)	74 ksi (510 MPa)		2
Medium carbon steel Q&T	85 ksi (586 MPa)	92 ksi (634 MPa)	120 ksi (827 MPa)		5
Alloy steel Q&T	120 ksi (827 MPa)	130 ksi (896 MPa)	150 ksi (1034 MPa)		8