Dimensions mm · values as the standard states them Size P s e m dw da n de m´ split_pin thread_alt w M6 1 10
9.78 – 10
≥ 11.05
5.7 – 6
≥ 8.8
6 – 6.75
2 – 2.25
—
≥ 2.8
1,6x14
—
3.2 – 3.5
(M7) 1 11
10.73 – 11
≥ 12.12
6.64 – 7
≥ 9.5
7 – 7.75
2 – 2.25
—
≥ 3.2
1,6x14
—
3.7 – 4
M8 1.25 13
12.73 – 13
≥ 14.38
7.64 – 8
≥ 11.3
8 – 8.75
2.5 – 2.75
—
≥ 3.8
2x16
M8x1
4.2 – 4.5
M10 1.5 17
16.73 – 17
≥ 18.9
8.64 – 9
≥ 15.3
10 – 10.8
2.8 – 3.05
—
≥ 4.6
2,5x20
M10x1
4.7 – 5
M12 1.75 19
18.67 – 19
≥ 20.1
9.64 – 10
≥ 17.2
12 – 13
3.5 – 3.8
16.57 – 17
≥ 5.3
3,2x22
M12x1,5
5.7 – 6
(M14) 2 22
21.67 – 22
≥ 24.49
10.57 – 11
≥ 20.2
14 – 15.1
3.5 – 3.8
18.48 – 19
≥ 5.9
3,2x25
(M14x1,5)
6.64 – 7
M16 2 24
23.67 – 24
≥ 26.75
11.57 – 12
≥ 22.2
16 – 17.3
4.5 – 4.8
21.48 – 22
≥ 5.9
4x28
M16x1,5
6.64 – 7
(M18) 2.5 27
26.16 – 27
≥ 29.56
12.3 – 13
≥ 24.8
18 – 19.5
4.5 – 4.8
24.3 – 25
≥ 6.7
4x32
(M18x2)
7.64 – 8
M20 2.5 30
29.16 – 30
≥ 32.95
12.3 – 13
≥ 27.7
20 – 21.6
4.5 – 4.8
27.3 – 28
≥ 6.7
4x36
M20x2
7.64 – 8
(M22) 2.5 32
31 – 32
≥ 35.03
14.3 – 15
≥ 29.5
22 – 23.8
5.5 – 5.8
29.3 – 30
≥ 9.1
5x36
(M22x2)
8.64 – 9
M24 3 36
35 – 36
≥ 39.55
14.3 – 15
≥ 33.2
24 – 25.9
5.5 – 5.8
33 – 34
≥ 9.1
5x40
—
8.64 – 9
(M27) 3 41
40 – 41
≥ 45.2
16.3 – 17
≥ 38
27 – 29.2
5.5 – 5.8
37 – 38
≥ 8.7
5x45
—
10.57 – 11
M30 3.5 46
45 – 46
≥ 50.85
17.3 – 18
≥ 42.7
30 – 32.4
7 – 7.36
41 – 42
≥ 8.7
6,3x50
—
10.57 – 11
(M33) 3.5 50
49 – 50
≥ 55.37
19.16 – 20
≥ 46.6
33 – 35.6
7 – 7.36
45 – 46
≥ 10.3
6,3x56
—
12.57 – 13
M36 4 55
53.8 – 55
≥ 60.79
19.16 – 20
≥ 51.1
36 – 38.9
7 – 7.36
49 – 50
≥ 10.37
6,3x63
—
12.57 – 13
(M39) 4 60
58.8 – 60
≥ 66.44
21.16 – 22
≥ 55.9
39 – 42.1
7 – 7.36
53.8 – 55
≥ 11.9
6,3x71
—
12.57 – 13
M42 4.5 65
63.8 – 65
≥ 72.02
22.16 – 23
≥ 60.6
42 – 45.4
9 – 9.36
56.8 – 58
≥ 11.9
8x71
—
13.57 – 14
(M45) 4.5 70
68.1 – 70
≥ 76.95
24.16 – 25
≥ 64.7
45 – 48.6
9 – 9.36
60.8 – 62
≥ 13.5
8x80
—
15.57 – 16
M48 5 75
73.1 – 75
≥ 82.6
24.16 – 25
≥ 69.4
48 – 51.8
9 – 9.36
63.8 – 65
≥ 13.5
8x80
—
15.57 – 16
(M52) 5 80
78.1 – 80
≥ 88.25
26.16 – 27
≥ 74.2
52 – 56.2
9 – 9.36
68.8 – 70
≥ 15
8x90
—
17.57 – 18
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.
Size sheet · DIN 937
M6
s width across flats 10
e width across corners ≥ 11.05
m height of the nut 5.7 – 6
dw bearing face diameter ≥ 8.8
da transition diameter 6 – 6.75
n groove width 2 – 2.25
m´ ≥ 2.8
split_pin 1,6x14
w 3.2 – 3.5 Thread · ISO 261/262
Pitch P 1
d2 5.35
d3 4.773
Tap drill 5
Stress area As 20.12 mm² Size sheet · DIN 937
M7
s width across flats 11
e width across corners ≥ 12.12
m height of the nut 6.64 – 7
dw bearing face diameter ≥ 9.5
da transition diameter 7 – 7.75
n groove width 2 – 2.25
m´ ≥ 3.2
split_pin 1,6x14
w 3.7 – 4 Thread · ISO 261/262
Pitch P 1
d2 6.35
d3 5.773
Tap drill 6
Stress area As 28.86 mm² Size sheet · DIN 937
M8
s width across flats 13
e width across corners ≥ 14.38
m height of the nut 7.64 – 8
dw bearing face diameter ≥ 11.3
da transition diameter 8 – 8.75
n groove width 2.5 – 2.75
m´ ≥ 3.8
split_pin 2x16
thread_alt alternative / fine thread M8x1
w 4.2 – 4.5 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 · DIN 937
M10
s width across flats 17
e width across corners ≥ 18.9
m height of the nut 8.64 – 9
dw bearing face diameter ≥ 15.3
da transition diameter 10 – 10.8
n groove width 2.8 – 3.05
m´ ≥ 4.6
split_pin 2,5x20
thread_alt alternative / fine thread M10x1
w 4.7 – 5 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 · DIN 937
M12
s width across flats 19
e width across corners ≥ 20.1
m height of the nut 9.64 – 10
dw bearing face diameter ≥ 17.2
da transition diameter 12 – 13
n groove width 3.5 – 3.8
de diameter of the crown 16.57 – 17
m´ ≥ 5.3
split_pin 3,2x22
thread_alt alternative / fine thread M12x1,5
w 5.7 – 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 · DIN 937
M14
s width across flats 22
e width across corners ≥ 24.49
m height of the nut 10.57 – 11
dw bearing face diameter ≥ 20.2
da transition diameter 14 – 15.1
n groove width 3.5 – 3.8
de diameter of the crown 18.48 – 19
m´ ≥ 5.9
split_pin 3,2x25
thread_alt alternative / fine thread (M14x1,5)
w 6.64 – 7 Thread · ISO 261/262
Pitch P 2
d2 12.701
d3 11.546
Tap drill 12
Stress area As 115.44 mm² Size sheet · DIN 937
M16
s width across flats 24
e width across corners ≥ 26.75
m height of the nut 11.57 – 12
dw bearing face diameter ≥ 22.2
da transition diameter 16 – 17.3
n groove width 4.5 – 4.8
de diameter of the crown 21.48 – 22
m´ ≥ 5.9
split_pin 4x28
thread_alt alternative / fine thread M16x1,5
w 6.64 – 7 Thread · ISO 261/262
Pitch P 2
d2 14.701
d3 13.546
Tap drill 14
Stress area As 156.67 mm² Size sheet · DIN 937
M18
s width across flats 27
e width across corners ≥ 29.56
m height of the nut 12.3 – 13
dw bearing face diameter ≥ 24.8
da transition diameter 18 – 19.5
n groove width 4.5 – 4.8
de diameter of the crown 24.3 – 25
m´ ≥ 6.7
split_pin 4x32
thread_alt alternative / fine thread (M18x2)
w 7.64 – 8 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 · DIN 937
M20
s width across flats 30
e width across corners ≥ 32.95
m height of the nut 12.3 – 13
dw bearing face diameter ≥ 27.7
da transition diameter 20 – 21.6
n groove width 4.5 – 4.8
de diameter of the crown 27.3 – 28
m´ ≥ 6.7
split_pin 4x36
thread_alt alternative / fine thread M20x2
w 7.64 – 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 · DIN 937
M22
s width across flats 32
e width across corners ≥ 35.03
m height of the nut 14.3 – 15
dw bearing face diameter ≥ 29.5
da transition diameter 22 – 23.8
n groove width 5.5 – 5.8
de diameter of the crown 29.3 – 30
m´ ≥ 9.1
split_pin 5x36
thread_alt alternative / fine thread (M22x2)
w 8.64 – 9 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 · DIN 937
M24
s width across flats 36
e width across corners ≥ 39.55
m height of the nut 14.3 – 15
dw bearing face diameter ≥ 33.2
da transition diameter 24 – 25.9
n groove width 5.5 – 5.8
de diameter of the crown 33 – 34
m´ ≥ 9.1
split_pin 5x40
w 8.64 – 9 Thread · ISO 261/262
Pitch P 3
d2 22.051
d3 20.319
Tap drill 21
Stress area As 352.5 mm² Size sheet · DIN 937
M27
s width across flats 41
e width across corners ≥ 45.2
m height of the nut 16.3 – 17
dw bearing face diameter ≥ 38
da transition diameter 27 – 29.2
n groove width 5.5 – 5.8
de diameter of the crown 37 – 38
m´ ≥ 8.7
split_pin 5x45
w 10.57 – 11 Thread · ISO 261/262
Pitch P 3
d2 25.051
d3 23.319
Tap drill 24
Stress area As 459.41 mm² Size sheet · DIN 937
M30
s width across flats 46
e width across corners ≥ 50.85
m height of the nut 17.3 – 18
dw bearing face diameter ≥ 42.7
da transition diameter 30 – 32.4
n groove width 7 – 7.36
de diameter of the crown 41 – 42
m´ ≥ 8.7
split_pin 6,3x50
w 10.57 – 11 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 · DIN 937
M33
s width across flats 50
e width across corners ≥ 55.37
m height of the nut 19.16 – 20
dw bearing face diameter ≥ 46.6
da transition diameter 33 – 35.6
n groove width 7 – 7.36
de diameter of the crown 45 – 46
m´ ≥ 10.3
split_pin 6,3x56
w 12.57 – 13 Thread · ISO 261/262
Pitch P 3.5
d2 30.727
d3 28.706
Tap drill 29.5
Stress area As 693.55 mm² Size sheet · DIN 937
M36
s width across flats 55
e width across corners ≥ 60.79
m height of the nut 19.16 – 20
dw bearing face diameter ≥ 51.1
da transition diameter 36 – 38.9
n groove width 7 – 7.36
de diameter of the crown 49 – 50
m´ ≥ 10.37
split_pin 6,3x63
w 12.57 – 13 Thread · ISO 261/262
Pitch P 4
d2 33.402
d3 31.093
Tap drill 32
Stress area As 816.72 mm² Size sheet · DIN 937
M39
s width across flats 60
e width across corners ≥ 66.44
m height of the nut 21.16 – 22
dw bearing face diameter ≥ 55.9
da transition diameter 39 – 42.1
n groove width 7 – 7.36
de diameter of the crown 53.8 – 55
m´ ≥ 11.9
split_pin 6,3x71
w 12.57 – 13 Thread · ISO 261/262
Pitch P 4
d2 36.402
d3 34.093
Tap drill 35
Stress area As 975.75 mm² Size sheet · DIN 937
M42
s width across flats 65
e width across corners ≥ 72.02
m height of the nut 22.16 – 23
dw bearing face diameter ≥ 60.6
da transition diameter 42 – 45.4
n groove width 9 – 9.36
de diameter of the crown 56.8 – 58
m´ ≥ 11.9
split_pin 8x71
w 13.57 – 14 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 · DIN 937
M45
s width across flats 70
e width across corners ≥ 76.95
m height of the nut 24.16 – 25
dw bearing face diameter ≥ 64.7
da transition diameter 45 – 48.6
n groove width 9 – 9.36
de diameter of the crown 60.8 – 62
m´ ≥ 13.5
split_pin 8x80
w 15.57 – 16 Thread · ISO 261/262
Pitch P 4.5
d2 42.077
d3 39.479
Tap drill 40.5
Stress area As 1306 mm² Size sheet · DIN 937
M48
s width across flats 75
e width across corners ≥ 82.6
m height of the nut 24.16 – 25
dw bearing face diameter ≥ 69.4
da transition diameter 48 – 51.8
n groove width 9 – 9.36
de diameter of the crown 63.8 – 65
m´ ≥ 13.5
split_pin 8x80
w 15.57 – 16 Thread · ISO 261/262
Pitch P 5
d2 44.752
d3 41.866
Tap drill 43
Stress area As 1473.15 mm² Size sheet · DIN 937
M52
s width across flats 80
e width across corners ≥ 88.25
m height of the nut 26.16 – 27
dw bearing face diameter ≥ 74.2
da transition diameter 52 – 56.2
n groove width 9 – 9.36
de diameter of the crown 68.8 – 70
m´ ≥ 15
split_pin 8x90
w 17.57 – 18 Thread · ISO 261/262
Pitch P 5
d2 48.752
d3 45.866
Tap drill 47
Stress area As 1757.83 mm² Provenance
Draft — values taken from a single source and not yet cross-checked.
fasteners.eu dimensions, lengths, materials, property classes, current norm, equivalent norms Accessed 2026-09-23 · For design and safety-critical use, consult the current edition of the standard.