ISO 4762 – Hexagon Socket Cap Head Screw Dimensions

ISO 4762 is the primary international standard for hexagon socket head cap screws (SHCS). These high-strength fasteners are designed with a cylindrical head and an internal hexagonal drive, enabling high-torque tightening in recessed or confined areas where traditional hex bolts cannot be used. ISO 4762 is the modern global equivalent to the German DIN 912 standard. For the vast majority of engineering applications, these two standards are considered functionally interchangeable, sharing identical dimensions for head diameter (d_k), head height (k), and socket size (s).

ISO 4762 Hexagon Socket Head Cap Screw Schematic

ISO 4762 - Dimensions
Thread Size		M1.6	M2	M2.5	M3	M4	M5	M6	M8	M10	M12	M14	M16	M20	M24	M30	M36	M42	M48	M56	M64
dk	Max	3.14	3.98	4.68	5.68	7.22	8.72	10.22	13.27	16.27	18.27	21.33	24.33	30.33	36.39	45.39	54.46	63.46	72.46	84.54	96.54
dk	Min	2.86	3.62	4.32	5.32	6.78	8.28	9.78	12.73	15.73	17.73	20.67	23.67	29.67	35.61	44.61	53.54	62.54	71.54	83.46	95.46
k	Max	1.6	2	2.5	3	4	5	6	8	10	12	14	16	20	24	30	36	42	48	56	64
k	Min	1.46	1.86	2.36	2.86	3.82	4.82	5.7	7.64	9.64	11.57	13.57	15.57	19.48	23.48	29.48	35.38	41.38	47.38	55.26	63.26
s	Nom	1.5	1.5	2	2.5	3	4	5	6	8	10	12	14	17	19	22	27	32	36	41	46
	Max	1.58	1.58	2.08	2.58	3.08	4.095	5.14	6.14	8.175	10.175	12.212	14.212	17.23	19.275	22.275	27.275	32.33	36.33	41.33	46.33
	Min	1.52	1.52	2.02	2.52	3.02	4.02	5.02	6.02	8.025	10.025	12.032	14.032	17.05	19.065	22.065	27.065	32.08	36.08	41.08	46.08
e	Min	1.733	1.733	2.303	2.873	3.443	4.583	5.723	6.863	9.149	11.429	13.716	15.996	19.437	21.734	25.154	30.854	36.571	41.131	46.831	52.531
t	Min	0.7	1	1.1	1.3	2	2.5	3	4	5	6	7	8	10	12	15.5	19	24	28	34	38
w	Min	0.55	0.55	0.85	1.15	1.4	1.9	2.3	3.3	4	4.8	5.8	6.8	8.6	10.4	13.1	15.3	16.3	17.5	19	22
r	Min	0.1	0.1	0.1	0.1	0.2	0.2	0.25	0.4	0.4	0.6	0.6	0.6	0.8	0.8	1	1	1.2	1.6	2	2
da	Max	2	2.6	3.1	3.6	4.7	5.7	6.8	9.2	11.2	13.7	15.7	17.7	22.4	26.4	33.4	39.4	45.6	52.6	63	71
ds	Max	1.6	2	2.5	3	4	5	6	8	10	12	14	16	20	24	30	36	42	48	56	64
ds	Min	1.46	1.86	2.36	2.86	3.82	4.82	5.82	7.78	9.78	11.73	13.73	15.73	19.67	23.67	29.67	35.61	41.61	47.61	55.54	63.54
dw	Min	2.72	3.48	4.18	5.07	6.53	8.03	9.38	12.33	15.33	17.23	20.17	23.17	28.87	34.81	43.61	52.54	61.34	70.34	82.26	94.26
b	Ref	15	16	17	18	20	22	24	28	32	36	40	44	52	60	72	84	96	108	124	140

Note: All measurement are in mm

Disclaimer: The dimensions presented on this page are based on the applicable industry standard. However, actual product measurements may vary slightly due to manufacturing practices, material selection, surface finish, and specified tolerance classes. Buyers and sourcing professionals are encouraged to verify final specifications with the manufacturer or supplier prior to procurement, particularly for critical applications.

Legend

dk – Head diameter.
da – Transition diameter (max).
ds – Shank diameter.
k – Head height.
s – Width across flats of the internal hexagon socket.
t – Minimum depth of the internal hexagon socket.
e – Width across corners of the internal hexagon socket (min).
dw – Minimum bearing diameter under the head.
b – Reference thread length.
r – Radius of the underhead fillet (min).
w – Minimum wall thickness between the socket and outer head diameter.
Ref (Reference value) – A theoretical dimension provided for information and design guidance only. Reference values (like b) are not requirements for inspection but assist in geometry calculation.

Technical Note

The maximum value of lg can be determined by:
lg max = nominal length − b
where b is the reference thread length.
The minimum value of ls can be determined by:
ls min = lg max − 5P
where P is the thread pitch.
Standard nominal lengths (l) according to ISO 4762 are generally available in the following ranges:
- For sizes M1.6 – M8: 2.5 mm to 80 mm
- For sizes M10 – M36: 16 mm to 200 mm
- For sizes M42 – M64: 50 mm to 300 mm

Standard Body Lengths and Tolerances
Nominal Length (l)	Min (mm)	Max (mm)
2.5 mm	2.3	2.7
3 mm	2.8	3.2
4 mm	3.76	4.24
5 mm	4.76	5.24
6 mm	5.76	6.24
8 mm	7.71	8.29
10 mm	9.71	10.29
12 mm	11.65	12.35
16 mm	15.65	16.35
20 mm	19.58	20.42
25 mm	24.58	25.42
30 mm	29.58	30.42
35 mm	34.5	35.5
40 mm	39.5	40.5
45 mm	44.5	45.5
50 mm	49.5	50.5
55 mm	54.4	55.6
60 mm	59.4	60.6
65 mm	64.4	65.6
70 mm	69.4	70.6
80 mm	79.4	80.6
90 mm	89.3	90.7
100 mm	99.3	100.7
110 mm	109.3	110.7
120 mm	119.3	120.7
130 mm	129.2	130.8
140 mm	139.2	140.8
150 mm	149.2	150.8
160 mm	159.2	160.8
180 mm	179.2	180.8
200 mm	199.075	200.925
220 mm	219.075	220.925
240 mm	239.075	240.925
260 mm	258.95	261.05
280 mm	278.95	281.05
300 mm	298.95	301.05

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