Dimensions mm · values as the standard states them Size P ds s e k b l > 125 b l ≤ 125 da c r dc k´ x1 M5 0.8 5
4.82 – 5
5
4.82 – 5
6.5
5.92 – 6.5
7
—
16
≤ 5.7
2
1.88 – 2.12
≥ 0.25
9.5
8.92 – 9.5
≥ 3.4
≤ 2
M6 1 6
5.82 – 6
6
5.82 – 6
8
7.42 – 8
8
—
18
≤ 6.8
2
1.88 – 2.12
≥ 0.25
10.5
9.8 – 10.5
≥ 4.1
≤ 2.5
M8 1.25 8
7.78 – 8
8
7.78 – 8
10
9.42 – 10
10
—
22
≤ 9.2
2
1.88 – 2.12
≥ 0.4
13.5
12.8 – 13.5
≥ 5.5
≤ 3.2
M10 1.5 10
9.78 – 10
10
9.78 – 10
13
12.3 – 13
13
32
26
≤ 11.2
3
2.88 – 3.12
≥ 0.4
16.5
15.8 – 16.5
≥ 6.9
≤ 3.8
M12 1.75 12
11.73 – 12
13
12.73 – 13
17
16.3 – 17
15
36
30
≤ 13.7
3
2.88 – 3.12
≥ 0.6
19.5
18.66 – 19.5
≥ 8.3
≤ 4.3
M16 2 16
15.73 – 16
17
16.73 – 17
22
21.16 – 22
20
44
38
≤ 17.7
4
3.85 – 4.15
≥ 0.6
25
24.16 – 25
≥ 11.1
≤ 5
M20 2.5 20
19.67 – 20
22
21.67 – 22
28
27.16 – 28
25
52
45
≤ 22.4
5
4.85 – 5.15
≥ 0.8
31
30 – 31
≥ 13.8
≤ 6.3
M24 3 24
23.67 – 24
24
23.67 – 24
32
31 – 32
28
60
54
≤ 26.4
6
5.85 – 6.15
≥ 0.9
36
35 – 36
≥ 15.2
≤ 7.5
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 10 9.71 – 10.29
16 1565 – 16.35
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
55 54.4 – 55.6
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
110 109.3 – 110.7
120 119.3 – 120.7
140 139.2 – 140.8
160 159.2 – 160.8
180 179.2 – 180.8
Size sheet · DIN 478
M5
ds shank diameter 5
s width across flats 5
e width across corners 6.5
k head height 7
b thread length (l ≤ 125) 16
da transition diameter ≤ 5.7
c thickness of the mounting collar 2
r fillet radius ≥ 0.25
dc 9.5
k´ minimum size of the head on the key ≥ 3.4
x1 thread run ≤ 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 Standard lengths
10 · 16 · 20 · 25 · 30
Size sheet · DIN 478
M6
ds shank diameter 6
s width across flats 6
e width across corners 8
k head height 8
b thread length (l ≤ 125) 18
da transition diameter ≤ 6.8
c thickness of the mounting collar 2
r fillet radius ≥ 0.25
dc 10.5
k´ minimum size of the head on the key ≥ 4.1
x1 thread run ≤ 2.5 Thread · ISO 261/262
Pitch P 1
d2 5.35
d3 4.773
Tap drill 5
Stress area As 20.12 mm² Standard lengths
10 · 16 · 20 · 25 · 30 · 35 · 40
Size sheet · DIN 478
M8
ds shank diameter 8
s width across flats 8
e width across corners 10
k head height 10
b thread length (l ≤ 125) 22
da transition diameter ≤ 9.2
c thickness of the mounting collar 2
r fillet radius ≥ 0.4
dc 13.5
k´ minimum size of the head on the key ≥ 5.5
x1 thread run ≤ 3.2 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 · 20 · 25 · 30 · 35 · 40 · 45
Size sheet · DIN 478
M10
ds shank diameter 10
s width across flats 10
e width across corners 13
k head height 13
b thread length (l > 125) 32
b thread length (l ≤ 125) 26
da transition diameter ≤ 11.2
c thickness of the mounting collar 3
r fillet radius ≥ 0.4
dc 16.5
k´ minimum size of the head on the key ≥ 6.9
x1 thread run ≤ 3.8 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 · 55 · 60
Size sheet · DIN 478
M12
ds shank diameter 12
s width across flats 13
e width across corners 17
k head height 15
b thread length (l > 125) 36
b thread length (l ≤ 125) 30
da transition diameter ≤ 13.7
c thickness of the mounting collar 3
r fillet radius ≥ 0.6
dc 19.5
k´ minimum size of the head on the key ≥ 8.3
x1 thread run ≤ 4.3 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 · 55 · 60 · 70 · 80 · 90
Size sheet · DIN 478
M16
ds shank diameter 16
s width across flats 17
e width across corners 22
k head height 20
b thread length (l > 125) 44
b thread length (l ≤ 125) 38
da transition diameter ≤ 17.7
c thickness of the mounting collar 4
r fillet radius ≥ 0.6
dc 25
k´ minimum size of the head on the key ≥ 11.1
x1 thread run ≤ 5 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 · 55 · 60 · 70 · 80 · 90 · 100 · 110 · 120 · 140
Size sheet · DIN 478
M20
ds shank diameter 20
s width across flats 22
e width across corners 28
k head height 25
b thread length (l > 125) 52
b thread length (l ≤ 125) 45
da transition diameter ≤ 22.4
c thickness of the mounting collar 5
r fillet radius ≥ 0.8
dc 31
k´ minimum size of the head on the key ≥ 13.8
x1 thread run ≤ 6.3 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
35 · 40 · 45 · 50 · 55 · 60 · 70 · 80 · 90 · 100 · 110 · 120 · 140 · 160 · 180
Size sheet · DIN 478
M24
ds shank diameter 24
s width across flats 24
e width across corners 32
k head height 28
b thread length (l > 125) 60
b thread length (l ≤ 125) 54
da transition diameter ≤ 26.4
c thickness of the mounting collar 6
r fillet radius ≥ 0.9
dc 36
k´ minimum size of the head on the key ≥ 15.2
x1 thread run ≤ 7.5 Thread · ISO 261/262
Pitch P 3
d2 22.051
d3 20.319
Tap drill 21
Stress area As 352.5 mm² Standard lengths
35 · 40 · 45 · 50 · 55 · 60 · 70 · 80 · 90 · 100 · 110 · 120 · 140 · 160 · 180
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.
Data notes (1) 8 value(s) omitted after consistency checks: M5 k: min 7.18 > max 6.82 in source — min/max omitted; M6 k: min 8.18 > max 7.82 in source — min/max omitted; M8 k: min 10.18 > max 9.82 in source — min/max omitted; M10 k: min 13.22 > max 12.78 in source — min/max omitted; M12 k: min 15.22 > max 14.78 in source — min/max omitted; M16 k: min 20.26 > max 19.74 in source — min/max omitted; M20 k: min 25.26 > max 24.74 in source — min/max omitted; M24 k: min 28.26 > max 27.74 in source — min/max omitted