Dimensions mm · values as the standard states them Size P s e k da r a1 dp kw p thread_alt z2 M6 1 8
7.78 – 8
≥ 8.79
5
4.85 – 5.15
≤ 6.8
≥ 0.25
≤ 3
4
3.82 – 4
≥ 3.4
1
M6
3
3 – 3.25
M8 1.25 10
9.78 – 10
≥ 11.05
6
5.85 – 6.15
≤ 9.2
≥ 0.4
≤ 3.75
5.5
5.32 – 5.5
≥ 4.1
1.25
M8
4
4 – 4.3
M10 1.5 13
12.73 – 13
≥ 14.38
7
6.82 – 7.18
≤ 11.2
≥ 0.4
≤ 4.5
7
6.78 – 7
≥ 4.8
1.5
M10
5
5 – 5.3
M12 1.75 16
15.73 – 16
≥ 17.77
9
8.82 – 9.18
≤ 13.7
≥ 0.6
≤ 5.25
8.5
8.28 – 8.5
≥ 6.2
1.75
M12
6
6 – 6.3
M16 2 18
17.73 – 18
≥ 19.92
11
10.79 – 11.21
≤ 17.7
≥ 0.6
≤ 6
12
11.73 – 12
≥ 7.6
2
M16
8
8 – 8.36
M20 2.5 24
23.67 – 24
≥ 26.75
14
13.79 – 14.21
≤ 22.4
≥ 0.8
≤ 7.5
15
14.73 – 15
≥ 9.7
2.5
M20x2
10
10 – 10.36
M24 3 30
29.67 – 30
≥ 33.53
17
16.79 – 17.21
≤ 26.4
≥ 0.8
≤ 9
18
17.73 – 18
≥ 11.8
3
M24x2
12
12 – 12.43
M30 3.5 36
35.38 – 36
≥ 39.98
21
20.74 – 21.26
≤ 33.4
≥ 1
≤ 10.5
23
22.67 – 23
≥ 14.5
3.5
M30x2
15
15 – 15.43
M36 4 46
45.38 – 46
≥ 51.28
25
24.74 – 25.26
≤ 39.4
≥ 1
≤ 12
28
27.67 – 28
≥ 17.3
4
M36x3
18
18 – 18.43
M42 4.5 55
54.26 – 55
≥ 61.31
30
29.74 – 30.26
≤ 45.6
≥ 1.2
≤ 13.5
32
31.61 – 32
≥ 20.8
4.5
M42x3
21
21 – 21.52
M48 5 65
64.26 – 65
≥ 72.61
34
33.69 – 34.31
≤ 52.6
≥ 1.6
≤ 15
38
37.61 – 38
≥ 23.6
5
M48x3
24
24 – 24.52
M56 5.5 75
74.26 – 75
≥ 83.91
40
39.69 – 40.31
≤ 63
≥ 2
≤ 16.5
45
44.61 – 45
≥ 27.8
5.5
M56x3
28
28 – 28.52
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.
Length tolerances 12 11.65 – 12.35
14 13.65 – 14.35
16 15.65 – 16.35
18 17.65 – 18.35
20 19.58 – 20.42
25 24.58 – 25.42
30 29.58 – 30.42
35 34.5 – 35.5
40 39.5 – 40.5
45 44.5 – 45.5
50 49.5 – 50.5
60 59.4 – 60.6
70 69.4 – 70.6
80 79.4 – 80.6
90 89.3 – 90.7
100 99.3 – 100.7
120 119.3 – 120.7
140 139.2 – 140.8
160 159.2 – 160.8
180 179.2 – 180.8
200 199.075 – 200.925
220 219.075 – 220.925
240 239.075 – 240.925
260 258.95 – 261.105
280 278.95 – 281.105
300 298.95 – 301.105
Size sheet · DIN 561 A
M6
s width across flats 8
e width across corners ≥ 8.79
k head height 5
da transition diameter ≤ 6.8
r fillet radius ≥ 0.25
a1 ≤ 3
dp diameter of the ejector 4
kw ≥ 3.4
p 1
thread_alt alternative / fine thread M6
z2 length of the ejector 3 Thread · ISO 261/262
Pitch P 1
d2 5.35
d3 4.773
Tap drill 5
Stress area As 20.12 mm² Standard lengths
12 · 14 · 16 · 18 · 20 · 25 · 30
Size sheet · DIN 561 A
M8
s width across flats 10
e width across corners ≥ 11.05
k head height 6
da transition diameter ≤ 9.2
r fillet radius ≥ 0.4
a1 ≤ 3.75
dp diameter of the ejector 5.5
kw ≥ 4.1
p 1.25
thread_alt alternative / fine thread M8
z2 length of the ejector 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 Standard lengths
16 · 18 · 20 · 25 · 30 · 35 · 40
Size sheet · DIN 561 A
M10
s width across flats 13
e width across corners ≥ 14.38
k head height 7
da transition diameter ≤ 11.2
r fillet radius ≥ 0.4
a1 ≤ 4.5
dp diameter of the ejector 7
kw ≥ 4.8
p 1.5
thread_alt alternative / fine thread M10
z2 length of the ejector 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 Standard lengths
20 · 25 · 30 · 35 · 40 · 45 · 50
Size sheet · DIN 561 A
M12
s width across flats 16
e width across corners ≥ 17.77
k head height 9
da transition diameter ≤ 13.7
r fillet radius ≥ 0.6
a1 ≤ 5.25
dp diameter of the ejector 8.5
kw ≥ 6.2
p 1.75
thread_alt alternative / fine thread M12
z2 length of the ejector 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 Standard lengths
25 · 30 · 35 · 40 · 45 · 50 · 60 · 70
Size sheet · DIN 561 A
M16
s width across flats 18
e width across corners ≥ 19.92
k head height 11
da transition diameter ≤ 17.7
r fillet radius ≥ 0.6
a1 ≤ 6
dp diameter of the ejector 12
kw ≥ 7.6
p 2
thread_alt alternative / fine thread M16
z2 length of the ejector 8 Thread · ISO 261/262
Pitch P 2
d2 14.701
d3 13.546
Tap drill 14
Stress area As 156.67 mm² Standard lengths
30 · 35 · 40 · 45 · 50 · 60 · 70 · 80 · 90
Size sheet · DIN 561 A
M20
s width across flats 24
e width across corners ≥ 26.75
k head height 14
da transition diameter ≤ 22.4
r fillet radius ≥ 0.8
a1 ≤ 7.5
dp diameter of the ejector 15
kw ≥ 9.7
p 2.5
thread_alt alternative / fine thread M20x2
z2 length of the ejector 10 Thread · ISO 261/262
Pitch P 2.5
d2 18.376
d3 16.933
Tap drill 17.5
Stress area As 244.79 mm² Standard lengths
40 · 45 · 50 · 60 · 70 · 80 · 90 · 100
Size sheet · DIN 561 A
M24
s width across flats 30
e width across corners ≥ 33.53
k head height 17
da transition diameter ≤ 26.4
r fillet radius ≥ 0.8
a1 ≤ 9
dp diameter of the ejector 18
kw ≥ 11.8
p 3
thread_alt alternative / fine thread M24x2
z2 length of the ejector 12 Thread · ISO 261/262
Pitch P 3
d2 22.051
d3 20.319
Tap drill 21
Stress area As 352.5 mm² Standard lengths
45 · 50 · 60 · 70 · 80 · 90 · 100 · 120
Size sheet · DIN 561 A
M30
s width across flats 36
e width across corners ≥ 39.98
k head height 21
da transition diameter ≤ 33.4
r fillet radius ≥ 1
a1 ≤ 10.5
dp diameter of the ejector 23
kw ≥ 14.5
p 3.5
thread_alt alternative / fine thread M30x2
z2 length of the ejector 15 Thread · ISO 261/262
Pitch P 3.5
d2 27.727
d3 25.706
Tap drill 26.5
Stress area As 560.59 mm² Standard lengths
60 · 70 · 80 · 90 · 100 · 120 · 140 · 160
Size sheet · DIN 561 A
M36
s width across flats 46
e width across corners ≥ 51.28
k head height 25
da transition diameter ≤ 39.4
r fillet radius ≥ 1
a1 ≤ 12
dp diameter of the ejector 28
kw ≥ 17.3
p 4
thread_alt alternative / fine thread M36x3
z2 length of the ejector 18 Thread · ISO 261/262
Pitch P 4
d2 33.402
d3 31.093
Tap drill 32
Stress area As 816.72 mm² Standard lengths
80 · 90 · 100 · 120 · 140 · 160 · 180 · 200
Size sheet · DIN 561 A
M42
s width across flats 55
e width across corners ≥ 61.31
k head height 30
da transition diameter ≤ 45.6
r fillet radius ≥ 1.2
a1 ≤ 13.5
dp diameter of the ejector 32
kw ≥ 20.8
p 4.5
thread_alt alternative / fine thread M42x3
z2 length of the ejector 21 Thread · ISO 261/262
Pitch P 4.5
d2 39.077
d3 36.479
Tap drill 37.5
Stress area As 1120.91 mm² Standard lengths
80 · 90 · 100 · 120 · 140 · 160 · 180 · 200 · 220 · 240 · 260
Size sheet · DIN 561 A
M48
s width across flats 65
e width across corners ≥ 72.61
k head height 34
da transition diameter ≤ 52.6
r fillet radius ≥ 1.6
a1 ≤ 15
dp diameter of the ejector 38
kw ≥ 23.6
p 5
thread_alt alternative / fine thread M48x3
z2 length of the ejector 24 Thread · ISO 261/262
Pitch P 5
d2 44.752
d3 41.866
Tap drill 43
Stress area As 1473.15 mm² Standard lengths
90 · 100 · 120 · 140 · 160 · 180 · 200 · 220 · 240 · 260 · 280 · 300
Size sheet · DIN 561 A
M56
s width across flats 75
e width across corners ≥ 83.91
k head height 40
da transition diameter ≤ 63
r fillet radius ≥ 2
a1 ≤ 16.5
dp diameter of the ejector 45
kw ≥ 27.8
p 5.5
thread_alt alternative / fine thread M56x3
z2 length of the ejector 28 Thread · ISO 261/262
Pitch P 5.5
d2 52.428
d3 49.252
Tap drill 50.5
Stress area As 2030.02 mm² Standard lengths
100 · 120 · 140 · 160 · 180 · 200 · 220 · 240 · 260 · 280 · 300
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.