Dimensions mm · values as the standard states them Size P ds dk s e k b 125 < l ≤ 200 b l > 200 b l ≤ 125 da c a r t M3 0.5 3
2.86 – 3
6
5.7 – 6
2
2.02 – 2.1
≥ 2.3
≤ 1.7
—
—
12
≤ 3.6
≈ 0.2
90°
2° 0
≥ 0.1
1.2
0.95 – 1.2
M4 0.7 4
3.82 – 4
8
7.64 – 8
2.5
2.52 – 2.6
≥ 2.87
≤ 2.3
—
—
14
≤ 4.7
≈ 0.3
90°
2° 0
≥ 0.2
1.8
1.5 – 1.8
M5 0.8 5
4.82 – 5
10
9.64 – 10
3
3.02 – 3.1
≥ 3.44
≤ 2.8
—
—
16
≤ 5.7
≈ 0.3
90°
2° 0
≥ 0.2
2.3
2.05 – 2.3
M6 1 6
5.82 – 6
12
11.57 – 12
4
4.02 – 4.12
≥ 4.58
≤ 3.3
24
—
18
≤ 6.8
≈ 0.3
90°
2° 0
≥ 0.3
2.5
2.25 – 2.5
M8 1.25 8
7.78 – 8
16
15.57 – 16
5
5.02 – 5.14
≥ 5.72
≤ 4.4
28
—
22
≤ 9.2
≈ 0.4
90°
2° 0
≥ 0.5
3.5
3.2 – 3.5
M10 1.5 10
9.78 – 10
20
19.48 – 20
6
6.02 – 6.14
≥ 6.86
≤ 5.5
32
45
26
≤ 11.2
≈ 0.5
90°
2° 0
≥ 0.5
4.4
4.1 – 4.4
M12 1.75 12
11.73 – 12
24
23.48 – 24
8
8.025 – 8.175
≥ 9.15
≤ 6.5
36
49
30
≤ 13.7
≈ 0.5
90°
2° 0
≥ 1
4.6
4.3 – 4.6
(M14) 2 14
13.73 – 14
27
26.48 – 27
10
10.025 – 10.175
≥ 11.43
≤ 7
40
53
34
≤ 15.7
≈ 0.5
90°
2° 0
≥ 1
4.8
4.5 – 4.8
M16 2 16
15.73 – 16
30
29.48 – 30
10
10.025 – 10.175
≥ 11.43
≤ 7.5
44
57
38
≤ 17.7
≈ 0.5
90°
2° 0
≥ 1
5.3
5 – 5.3
(M18) 2.5 18
17.73 – 18
33
32.38 – 33
12
12.032 – 12.212
≥ 13.72
≤ 8
48
61
42
≤ 20.2
≈ 0.5
90°
2° 0
≥ 1
5.5
5.2 – 5.5
M20 2.5 20
19.67 – 20
36
35.38 – 36
12
12.032 – 12.212
≥ 13.72
≤ 8.5
52
65
46
≤ 22.4
≈ 0.5
90°
2° 0
≥ 1
5.9
5.6 – 5.9
(M22) 2.5 22
21.67 – 22
36
35.38 – 36
14
14.032 – 14.212
≥ 16
≤ 13.1
56
69
50
≤ 24.4
≈ 1
60°
2° 0
≥ 1
8.8
8.44 – 8.8
M24 3 24
23.67 – 24
39
38.38 – 39
14
14.032 – 14.212
≥ 16
≤ 14
60
73
54
≤ 26.4
≈ 1
60°
2° 0
≥ 1.6
10.3
9.87 – 10.3
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 8 7.71 – 8.29
10 9.71 – 10.29
12 11.65 – 12.35
16 15.65 – 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
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
Size sheet · DIN 7991
M3
ds shank diameter 3
dk head diameter 6
s width across flats 2
e width across corners ≥ 2.3
k head height ≤ 1.7
b thread length (l ≤ 125) 12
da transition diameter ≤ 3.6
c ≈ 0.2
a 90°
r fillet radius ≥ 0.1
t groove depth 1.2 Thread · ISO 261/262
Pitch P 0.5
d2 2.675
d3 2.387
Tap drill 2.5
Stress area As 5.03 mm² Standard lengths
8 · 10 · 12 · 16 · 20 · 25 · 30
Size sheet · DIN 7991
M4
ds shank diameter 4
dk head diameter 8
s width across flats 2.5
e width across corners ≥ 2.87
k head height ≤ 2.3
b thread length (l ≤ 125) 14
da transition diameter ≤ 4.7
c ≈ 0.3
a 90°
r fillet radius ≥ 0.2
t groove depth 1.8 Thread · ISO 261/262
Pitch P 0.7
d2 3.545
d3 3.141
Tap drill 3.3
Stress area As 8.78 mm² Standard lengths
8 · 10 · 12 · 16 · 20 · 25 · 30 · 35 · 40
Size sheet · DIN 7991
M5
ds shank diameter 5
dk head diameter 10
s width across flats 3
e width across corners ≥ 3.44
k head height ≤ 2.8
b thread length (l ≤ 125) 16
da transition diameter ≤ 5.7
c ≈ 0.3
a 90°
r fillet radius ≥ 0.2
t groove depth 2.3 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
8 · 10 · 12 · 16 · 20 · 25 · 30 · 35 · 40 · 50
Size sheet · DIN 7991
M6
ds shank diameter 6
dk head diameter 12
s width across flats 4
e width across corners ≥ 4.58
k head height ≤ 3.3
b thread length (125 < l ≤ 200) 24
b thread length (l ≤ 125) 18
da transition diameter ≤ 6.8
c ≈ 0.3
a 90°
r fillet radius ≥ 0.3
t groove depth 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
8 · 10 · 12 · 16 · 20 · 25 · 30 · 35 · 40 · 50
Size sheet · DIN 7991
M8
ds shank diameter 8
dk head diameter 16
s width across flats 5
e width across corners ≥ 5.72
k head height ≤ 4.4
b thread length (125 < l ≤ 200) 28
b thread length (l ≤ 125) 22
da transition diameter ≤ 9.2
c ≈ 0.4
a 90°
r fillet radius ≥ 0.5
t groove depth 3.5 Thread · ISO 261/262
Pitch P 1.25
d2 7.188
d3 6.466
Tap drill 6.75
Stress area As 36.61 mm² Standard lengths
10 · 12 · 16 · 20 · 25 · 30 · 35 · 40 · 50 · 60
Size sheet · DIN 7991
M10
ds shank diameter 10
dk head diameter 20
s width across flats 6
e width across corners ≥ 6.86
k head height ≤ 5.5
b thread length (125 < l ≤ 200) 32
b thread length (l > 200) 45
b thread length (l ≤ 125) 26
da transition diameter ≤ 11.2
c ≈ 0.5
a 90°
r fillet radius ≥ 0.5
t groove depth 4.4 Thread · ISO 261/262
Pitch P 1.5
d2 9.026
d3 8.16
Tap drill 8.5
Stress area As 57.99 mm² Standard lengths
12 · 16 · 20 · 25 · 30 · 35 · 40 · 50 · 60 · 70
Size sheet · DIN 7991
M12
ds shank diameter 12
dk head diameter 24
s width across flats 8
e width across corners ≥ 9.15
k head height ≤ 6.5
b thread length (125 < l ≤ 200) 36
b thread length (l > 200) 49
b thread length (l ≤ 125) 30
da transition diameter ≤ 13.7
c ≈ 0.5
a 90°
r fillet radius ≥ 1
t groove depth 4.6 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
20 · 25 · 30 · 35 · 40 · 50 · 60 · 70
Size sheet · DIN 7991
M14
ds shank diameter 14
dk head diameter 27
s width across flats 10
e width across corners ≥ 11.43
k head height ≤ 7
b thread length (125 < l ≤ 200) 40
b thread length (l > 200) 53
b thread length (l ≤ 125) 34
da transition diameter ≤ 15.7
c ≈ 0.5
a 90°
r fillet radius ≥ 1
t groove depth 4.8 Thread · ISO 261/262
Pitch P 2
d2 12.701
d3 11.546
Tap drill 12
Stress area As 115.44 mm² Standard lengths
25 · 30 · 35 · 40 · 50 · 60 · 70 · 80
Size sheet · DIN 7991
M16
ds shank diameter 16
dk head diameter 30
s width across flats 10
e width across corners ≥ 11.43
k head height ≤ 7.5
b thread length (125 < l ≤ 200) 44
b thread length (l > 200) 57
b thread length (l ≤ 125) 38
da transition diameter ≤ 17.7
c ≈ 0.5
a 90°
r fillet radius ≥ 1
t groove depth 5.3 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 · 50 · 60 · 70 · 80 · 90
Size sheet · DIN 7991
M18
ds shank diameter 18
dk head diameter 33
s width across flats 12
e width across corners ≥ 13.72
k head height ≤ 8
b thread length (125 < l ≤ 200) 48
b thread length (l > 200) 61
b thread length (l ≤ 125) 42
da transition diameter ≤ 20.2
c ≈ 0.5
a 90°
r fillet radius ≥ 1
t groove depth 5.5 Thread · ISO 261/262
Pitch P 2.5
d2 16.376
d3 14.933
Tap drill 15.5
Stress area As 192.47 mm² Standard lengths
35 · 40 · 50 · 60 · 70 · 80 · 90 · 100
Size sheet · DIN 7991
M20
ds shank diameter 20
dk head diameter 36
s width across flats 12
e width across corners ≥ 13.72
k head height ≤ 8.5
b thread length (125 < l ≤ 200) 52
b thread length (l > 200) 65
b thread length (l ≤ 125) 46
da transition diameter ≤ 22.4
c ≈ 0.5
a 90°
r fillet radius ≥ 1
t groove depth 5.9 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 · 50 · 60 · 70 · 80 · 90 · 100
Size sheet · DIN 7991
M22
ds shank diameter 22
dk head diameter 36
s width across flats 14
e width across corners ≥ 16
k head height ≤ 13.1
b thread length (125 < l ≤ 200) 56
b thread length (l > 200) 69
b thread length (l ≤ 125) 50
da transition diameter ≤ 24.4
c ≈ 1
a 60°
r fillet radius ≥ 1
t groove depth 8.8 Thread · ISO 261/262
Pitch P 2.5
d2 20.376
d3 18.933
Tap drill 19.5
Stress area As 303.4 mm² Standard lengths
40 · 50 · 60 · 70 · 80 · 90 · 100
Size sheet · DIN 7991
M24
ds shank diameter 24
dk head diameter 39
s width across flats 14
e width across corners ≥ 16
k head height ≤ 14
b thread length (125 < l ≤ 200) 60
b thread length (l > 200) 73
b thread length (l ≤ 125) 54
da transition diameter ≤ 26.4
c ≈ 1
a 60°
r fillet radius ≥ 1.6
t groove depth 10.3 Thread · ISO 261/262
Pitch P 3
d2 22.051
d3 20.319
Tap drill 21
Stress area As 352.5 mm² Standard lengths
50 · 60 · 70 · 80 · 90 · 100
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 7991, ISO 10642. It does not match the official ISO 10642 preview, so it is kept as the DIN table.