Dimensions mm · values as the standard states them Size P s e k b 125 < l ≤ 200 b l > 200 b l ≤ 125 c r M3 0.5 5.5
6.01
2
18
—
12
0.15 – 0.4
0.1
M4 0.7 7
7.66
2.8
20
—
14
0.15 – 0.4
0.2
M5 0.8 8
8.79
3.5
22
—
16
0.15 – 0.5
0.2
M6 1 10
11.05
4
24
—
18
0.15 – 0.5
0.25
M8 1.25 13
14.38
5.3
28
—
22
0.15 – 0.6
0.4
M10 1.5 16
DIN 17
17.77
6.4
32
45
26
0.15 – 0.6
0.4
M12 1.75 18
DIN 19
20.03
7.5
36
49
30
0.15 – 0.6
0.6
M14 2 21
DIN 22
23.36
8.8
40
53
34
0.15 – 0.6
0.6
M16 2 24
26.75
10
44
57
38
0.2 – 0.8
0.6
M18 2.5 27
30.14
11.5
48
61
42
0.2 – 0.8
0.6
M20 2.5 30
33.53
12.5
52
65
46
0.2 – 0.8
0.8
M22 2.5 34
DIN 32
37.72
14
56
69
50
0.2 – 0.8
0.8
M24 3 36
39.98
15
60
73
54
0.2 – 0.8
0.8
M27 3 41
45.2
17
66
79
60
0.2 – 0.8
1
M30 3.5 46
50.85
18.7
72
85
66
0.2 – 0.8
1
M36 4 55
60.79
22.5
84
97
—
0.2 – 0.8
1
M42 4.5 65
71.3
26
96
109
—
0.3 – 1
1.2
M48 5 75
82.6
30
108
121
—
0.3 – 1
1.6
M56 5.5 85
93.56
35
—
137
—
0.3 – 1
2
M64 6 95
104.9
40
—
153
—
0.3 – 1
2
Ranges read min – max; ≤ / ≥ where the standard gives one limit, ≈ for approximate values. Sizes in (brackets) are non-preferred. Select a row for its size sheet. Cells marked DIN show where DIN 931 used a different value.
Size sheet · ISO 4014
M3
s width across flats 5.5
e width across corners 6.01
k head height 2
b thread length (125 < l ≤ 200) 18
b thread length (l ≤ 125) 12
c 0.15 – 0.4
r fillet radius 0.1 Thread · ISO 261/262
Pitch P 0.5
d2 2.675
d3 2.387
Tap drill 2.5
Stress area As 5.03 mm² Size sheet · ISO 4014
M4
s width across flats 7
e width across corners 7.66
k head height 2.8
b thread length (125 < l ≤ 200) 20
b thread length (l ≤ 125) 14
c 0.15 – 0.4
r fillet radius 0.2 Thread · ISO 261/262
Pitch P 0.7
d2 3.545
d3 3.141
Tap drill 3.3
Stress area As 8.78 mm² Size sheet · ISO 4014
M5
s width across flats 8
e width across corners 8.79
k head height 3.5
b thread length (125 < l ≤ 200) 22
b thread length (l ≤ 125) 16
c 0.15 – 0.5
r fillet radius 0.2 Thread · ISO 261/262
Pitch P 0.8
d2 4.48
d3 4.019
Tap drill 4.2
Stress area As 14.18 mm² Size sheet · ISO 4014
M6
s width across flats 10
e width across corners 11.05
k head height 4
b thread length (125 < l ≤ 200) 24
b thread length (l ≤ 125) 18
c 0.15 – 0.5
r fillet radius 0.25 Thread · ISO 261/262
Pitch P 1
d2 5.35
d3 4.773
Tap drill 5
Stress area As 20.12 mm² Size sheet · ISO 4014
M8
s width across flats 13
e width across corners 14.38
k head height 5.3
b thread length (125 < l ≤ 200) 28
b thread length (l ≤ 125) 22
c 0.15 – 0.6
r fillet radius 0.4 Thread · ISO 261/262
Pitch P 1.25
d2 7.188
d3 6.466
Tap drill 6.75
Stress area As 36.61 mm² Size sheet · ISO 4014
M10
s width across flats 16
e width across corners 17.77
k head height 6.4
b thread length (125 < l ≤ 200) 32
b thread length (l > 200) 45
b thread length (l ≤ 125) 26
c 0.15 – 0.6
r fillet radius 0.4 Thread · ISO 261/262
Pitch P 1.5
d2 9.026
d3 8.16
Tap drill 8.5
Stress area As 57.99 mm² Size sheet · ISO 4014
M12
s width across flats 18
e width across corners 20.03
k head height 7.5
b thread length (125 < l ≤ 200) 36
b thread length (l > 200) 49
b thread length (l ≤ 125) 30
c 0.15 – 0.6
r fillet radius 0.6 Thread · ISO 261/262
Pitch P 1.75
d2 10.863
d3 9.853
Tap drill 10.25
Stress area As 84.27 mm² Size sheet · ISO 4014
M14
s width across flats 21
e width across corners 23.36
k head height 8.8
b thread length (125 < l ≤ 200) 40
b thread length (l > 200) 53
b thread length (l ≤ 125) 34
c 0.15 – 0.6
r fillet radius 0.6 Thread · ISO 261/262
Pitch P 2
d2 12.701
d3 11.546
Tap drill 12
Stress area As 115.44 mm² Size sheet · ISO 4014
M16
s width across flats 24
e width across corners 26.75
k head height 10
b thread length (125 < l ≤ 200) 44
b thread length (l > 200) 57
b thread length (l ≤ 125) 38
c 0.2 – 0.8
r fillet radius 0.6 Thread · ISO 261/262
Pitch P 2
d2 14.701
d3 13.546
Tap drill 14
Stress area As 156.67 mm² Size sheet · ISO 4014
M18
s width across flats 27
e width across corners 30.14
k head height 11.5
b thread length (125 < l ≤ 200) 48
b thread length (l > 200) 61
b thread length (l ≤ 125) 42
c 0.2 – 0.8
r fillet radius 0.6 Thread · ISO 261/262
Pitch P 2.5
d2 16.376
d3 14.933
Tap drill 15.5
Stress area As 192.47 mm² Size sheet · ISO 4014
M20
s width across flats 30
e width across corners 33.53
k head height 12.5
b thread length (125 < l ≤ 200) 52
b thread length (l > 200) 65
b thread length (l ≤ 125) 46
c 0.2 – 0.8
r fillet radius 0.8 Thread · ISO 261/262
Pitch P 2.5
d2 18.376
d3 16.933
Tap drill 17.5
Stress area As 244.79 mm² Size sheet · ISO 4014
M22
s width across flats 34
e width across corners 37.72
k head height 14
b thread length (125 < l ≤ 200) 56
b thread length (l > 200) 69
b thread length (l ≤ 125) 50
c 0.2 – 0.8
r fillet radius 0.8 Thread · ISO 261/262
Pitch P 2.5
d2 20.376
d3 18.933
Tap drill 19.5
Stress area As 303.4 mm² Size sheet · ISO 4014
M24
s width across flats 36
e width across corners 39.98
k head height 15
b thread length (125 < l ≤ 200) 60
b thread length (l > 200) 73
b thread length (l ≤ 125) 54
c 0.2 – 0.8
r fillet radius 0.8 Thread · ISO 261/262
Pitch P 3
d2 22.051
d3 20.319
Tap drill 21
Stress area As 352.5 mm² Size sheet · ISO 4014
M27
s width across flats 41
e width across corners 45.2
k head height 17
b thread length (125 < l ≤ 200) 66
b thread length (l > 200) 79
b thread length (l ≤ 125) 60
c 0.2 – 0.8
r fillet radius 1 Thread · ISO 261/262
Pitch P 3
d2 25.051
d3 23.319
Tap drill 24
Stress area As 459.41 mm² Size sheet · ISO 4014
M30
s width across flats 46
e width across corners 50.85
k head height 18.7
b thread length (125 < l ≤ 200) 72
b thread length (l > 200) 85
b thread length (l ≤ 125) 66
c 0.2 – 0.8
r fillet radius 1 Thread · ISO 261/262
Pitch P 3.5
d2 27.727
d3 25.706
Tap drill 26.5
Stress area As 560.59 mm² Size sheet · ISO 4014
M36
s width across flats 55
e width across corners 60.79
k head height 22.5
b thread length (125 < l ≤ 200) 84
b thread length (l > 200) 97
c 0.2 – 0.8
r fillet radius 1 Thread · ISO 261/262
Pitch P 4
d2 33.402
d3 31.093
Tap drill 32
Stress area As 816.72 mm² Size sheet · ISO 4014
M42
s width across flats 65
e width across corners 71.3
k head height 26
b thread length (125 < l ≤ 200) 96
b thread length (l > 200) 109
c 0.3 – 1
r fillet radius 1.2 Thread · ISO 261/262
Pitch P 4.5
d2 39.077
d3 36.479
Tap drill 37.5
Stress area As 1120.91 mm² Size sheet · ISO 4014
M48
s width across flats 75
e width across corners 82.6
k head height 30
b thread length (125 < l ≤ 200) 108
b thread length (l > 200) 121
c 0.3 – 1
r fillet radius 1.6 Thread · ISO 261/262
Pitch P 5
d2 44.752
d3 41.866
Tap drill 43
Stress area As 1473.15 mm² Size sheet · ISO 4014
M56
s width across flats 85
e width across corners 93.56
k head height 35
b thread length (l > 200) 137
c 0.3 – 1
r fillet radius 2 Thread · ISO 261/262
Pitch P 5.5
d2 52.428
d3 49.252
Tap drill 50.5
Stress area As 2030.02 mm² Size sheet · ISO 4014
M64
s width across flats 95
e width across corners 104.9
k head height 40
b thread length (l > 200) 153
c 0.3 – 1
r fillet radius 2 Thread · ISO 261/262
Pitch P 6
d2 60.103
d3 56.639
Tap drill 58
Stress area As 2675.97 mm² Provenance
Draft — values taken from a single source and not yet cross-checked.
Accessed 2026-09-23 · For design and safety-critical use, consult the current edition of the standard.
Data notes (1) The source publishes one identical table for DIN 931, ISO 4014. The source lists separate DIN and ISO widths across flats; this record uses its own column. All other dimensions are ISO-identical per the Würth DIN→ISO changeover table.