Dimensions mm · values as the standard states them Size P s e m h dw da r C dc m´ thread_alt M5 0.8 8
7.78 – 8
≥ 8.79
≥ 4.7
≤ 6.2
≥ 9.8
5 – 5.75
≤ 0.3
≥ 1
≤ 11.8
≥ 2.2
—
M6 1 10
9.78 – 10
≥ 11.05
≥ 5.7
≤ 7.3
≥ 12.2
6 – 6.75
≤ 0.36
≥ 1.1
≤ 14.2
≥ 3.1
—
M8 1.25 13
12.73 – 13
≥ 14.38
≥ 7.6
≤ 9.4
≥ 15.8
8 – 8.75
≤ 0.48
≥ 1.2
≤ 17.9
≥ 4.5
M8x1
M10 1.5 15
14.73 – 15
≥ 16.64
≥ 9.6
≤ 11.4
≥ 19.6
10 – 10.8
≤ 0.6
≥ 1.5
≤ 21.8
≥ 5.5
(M10x1)
M12 1.75 18
17.73 – 18
≥ 20.03
≥ 11.6
≤ 13.8
≥ 23.8
12 – 13
≤ 0.72
≥ 1.8
≤ 26
≥ 6.7
(M10x1,25)
(M14) 2 21
20.67 – 21
≥ 23.36
≥ 13.3
≤ 15.9
≥ 27.6
14 – 15.1
≤ 0.88
≥ 2.1
≤ 29.9
≥ 7.8
(M14x1,5)
M16 2 24
23.67 – 24
≥ 26.75
≥ 15.3
≤ 18.3
≥ 31.9
16 – 17.3
≤ 0.96
≥ 2.4
≤ 34.5
≥ 9
M16x1,5
M20 2.5 30
29.16 – 30
≥ 32.95
≥ 18.9
≤ 22.4
≥ 39.9
20 – 21.6
≤ 1.2
≥ 3
≤ 42.8
≥ 11.1
M20x1,5
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
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
45 44.5 – 45.5
50 49.5 – 50.5
55 54.4 – 55.6
60 59.4 – 60.6
65 64.4 – 65.5
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
130 129.2 – 130.8
140 139.2 – 140.8
150 149.2 – 150.8
160 159.2 – 160.8
180 179.2 – 180.8
200 199 – 201
Size sheet · DIN 6921
M5
s width across flats 8
e width across corners ≥ 8.79
m ≥ 4.7
h ≤ 6.2
dw bearing face diameter ≥ 9.8
da transition diameter 5 – 5.75
r fillet radius ≤ 0.3
C ≥ 1
dc ≤ 11.8
m´ ≥ 2.2 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 · 12 · 16 · 20 · 25 · 30 · 35 · 40 · 45 · 50
Size sheet · DIN 6921
M6
s width across flats 10
e width across corners ≥ 11.05
m ≥ 5.7
h ≤ 7.3
dw bearing face diameter ≥ 12.2
da transition diameter 6 – 6.75
r fillet radius ≤ 0.36
C ≥ 1.1
dc ≤ 14.2
m´ ≥ 3.1 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 · 16 · 20 · 25 · 30 · 35 · 40 · 45 · 50 · 55 · 60
Size sheet · DIN 6921
M8
s width across flats 13
e width across corners ≥ 14.38
m ≥ 7.6
h ≤ 9.4
dw bearing face diameter ≥ 15.8
da transition diameter 8 – 8.75
r fillet radius ≤ 0.48
C ≥ 1.2
dc ≤ 17.9
m´ ≥ 4.5
thread_alt alternative / fine thread M8x1 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 · 50 · 55 · 60 · 65 · 70 · 80
Size sheet · DIN 6921
M10
s width across flats 15
e width across corners ≥ 16.64
m ≥ 9.6
h ≤ 11.4
dw bearing face diameter ≥ 19.6
da transition diameter 10 – 10.8
r fillet radius ≤ 0.6
C ≥ 1.5
dc ≤ 21.8
m´ ≥ 5.5
thread_alt alternative / fine thread (M10x1) 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 · 65 · 70 · 80 · 90 · 100
Size sheet · DIN 6921
M12
s width across flats 18
e width across corners ≥ 20.03
m ≥ 11.6
h ≤ 13.8
dw bearing face diameter ≥ 23.8
da transition diameter 12 – 13
r fillet radius ≤ 0.72
C ≥ 1.8
dc ≤ 26
m´ ≥ 6.7
thread_alt alternative / fine thread (M10x1,25) 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 · 65 · 70 · 80 · 90 · 100 · 110 · 120
Size sheet · DIN 6921
M14
s width across flats 21
e width across corners ≥ 23.36
m ≥ 13.3
h ≤ 15.9
dw bearing face diameter ≥ 27.6
da transition diameter 14 – 15.1
r fillet radius ≤ 0.88
C ≥ 2.1
dc ≤ 29.9
m´ ≥ 7.8
thread_alt alternative / fine thread (M14x1,5) Thread · ISO 261/262
Pitch P 2
d2 12.701
d3 11.546
Tap drill 12
Stress area As 115.44 mm² Standard lengths
30 · 35 · 40 · 45 · 50 · 55 · 60 · 65 · 70 · 80 · 90 · 100 · 110 · 120 · 130 · 140
Size sheet · DIN 6921
M16
s width across flats 24
e width across corners ≥ 26.75
m ≥ 15.3
h ≤ 18.3
dw bearing face diameter ≥ 31.9
da transition diameter 16 – 17.3
r fillet radius ≤ 0.96
C ≥ 2.4
dc ≤ 34.5
m´ ≥ 9
thread_alt alternative / fine thread M16x1,5 Thread · ISO 261/262
Pitch P 2
d2 14.701
d3 13.546
Tap drill 14
Stress area As 156.67 mm² Standard lengths
35 · 40 · 45 · 50 · 55 · 60 · 65 · 70 · 80 · 90 · 100 · 110 · 120 · 130 · 140 · 150 · 160
Size sheet · DIN 6921
M20
s width across flats 30
e width across corners ≥ 32.95
m ≥ 18.9
h ≤ 22.4
dw bearing face diameter ≥ 39.9
da transition diameter 20 – 21.6
r fillet radius ≤ 1.2
C ≥ 3
dc ≤ 42.8
m´ ≥ 11.1
thread_alt alternative / fine thread M20x1,5 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 · 55 · 60 · 65 · 70 · 80 · 90 · 100 · 110 · 120 · 130 · 140 · 150 · 160 · 180 · 200
Provenance
Draft — values taken from a single source and not yet cross-checked.
fasteners.eu dimensions, lengths, materials, property classes, current norm, equivalent norms Otto Roth status Accessed 2026-09-23 · For design and safety-critical use, consult the current edition of the standard.