Dimensions mm · values as the standard states them Size P d1 s e m da a mass M6 1 14
h13
10
h13
≥ 11.05
9
js15
6 – 6.75
3
js14
6
M8 1.25 18
h13
13
h13
≥ 14.38
12
js15
8 – 8.75
3.5
js14
12
M10 1.5 22
h13
16
h13
≥ 17.77
15
js15
10 – 10.8
4
js14
22
M12 1.75 25
h13
18
h13
≥ 20.03
18
js15
12 – 13
4
js14
30
M16 2 31
h13
24
h13
≥ 26.75
24
js15
16 – 17.3
5
js14
68
M20 2.5 37
h13
30
h13
≥ 33.53
30
js15
20 – 21.6
6
js14
124
M24 3 45
h13
36
h14
≥ 39.98
36
js15
24 – 25.9
6
js14
219
M27 3 50
h13
41
h14
≥ 45.63
40
js15
27 – 29.1
7
js14
320
M30 3.5 58
h13
46
h14
≥ 51.28
45
js15
30 – 32.4
8
js14
464
M36 4 68
h13
55
h14
≥ 61.31
54
js15
36 – 38.9
10
js14
790
M42 4.5 80
h13
65
h14
≥ 72.61
63
js15
42 – 45.4
12
js14
1290
M48 5 92
h13
75
h14
≥ 83.91
72
js15
48 – 51.8
14
js14
1970
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 6331
M6
d1 external diameter of the nut 14
s width across flats 10
e width across corners ≥ 11.05
m nut height 9
da transition diameter 6 – 6.75
a Shoulder height 3
mass mass per 1000 pieces (kg) 6 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 6331
M8
d1 external diameter of the nut 18
s width across flats 13
e width across corners ≥ 14.38
m nut height 12
da transition diameter 8 – 8.75
a Shoulder height 3.5
mass mass per 1000 pieces (kg) 12 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 6331
M10
d1 external diameter of the nut 22
s width across flats 16
e width across corners ≥ 17.77
m nut height 15
da transition diameter 10 – 10.8
a Shoulder height 4
mass mass per 1000 pieces (kg) 22 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 6331
M12
d1 external diameter of the nut 25
s width across flats 18
e width across corners ≥ 20.03
m nut height 18
da transition diameter 12 – 13
a Shoulder height 4
mass mass per 1000 pieces (kg) 30 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 6331
M16
d1 external diameter of the nut 31
s width across flats 24
e width across corners ≥ 26.75
m nut height 24
da transition diameter 16 – 17.3
a Shoulder height 5
mass mass per 1000 pieces (kg) 68 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 6331
M20
d1 external diameter of the nut 37
s width across flats 30
e width across corners ≥ 33.53
m nut height 30
da transition diameter 20 – 21.6
a Shoulder height 6
mass mass per 1000 pieces (kg) 124 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 6331
M24
d1 external diameter of the nut 45
s width across flats 36
e width across corners ≥ 39.98
m nut height 36
da transition diameter 24 – 25.9
a Shoulder height 6
mass mass per 1000 pieces (kg) 219 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 6331
M27
d1 external diameter of the nut 50
s width across flats 41
e width across corners ≥ 45.63
m nut height 40
da transition diameter 27 – 29.1
a Shoulder height 7
mass mass per 1000 pieces (kg) 320 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 6331
M30
d1 external diameter of the nut 58
s width across flats 46
e width across corners ≥ 51.28
m nut height 45
da transition diameter 30 – 32.4
a Shoulder height 8
mass mass per 1000 pieces (kg) 464 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 6331
M36
d1 external diameter of the nut 68
s width across flats 55
e width across corners ≥ 61.31
m nut height 54
da transition diameter 36 – 38.9
a Shoulder height 10
mass mass per 1000 pieces (kg) 790 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 6331
M42
d1 external diameter of the nut 80
s width across flats 65
e width across corners ≥ 72.61
m nut height 63
da transition diameter 42 – 45.4
a Shoulder height 12
mass mass per 1000 pieces (kg) 1290 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 6331
M48
d1 external diameter of the nut 92
s width across flats 75
e width across corners ≥ 83.91
m nut height 72
da transition diameter 48 – 51.8
a Shoulder height 14
mass mass per 1000 pieces (kg) 1970 Thread · ISO 261/262
Pitch P 5
d2 44.752
d3 41.866
Tap drill 43
Stress area As 1473.15 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.