Dimensions mm · values as the standard states them Size P s e m dw mass mw M5 0.8 7.64 – 8
9.93 – 11.3
3.52 – 4
≥ 6.7
1.31
≥ 2.5
M6 1 9.64 – 10
12.53 – 14.1
4.52 – 5
≥ 8.7
2.77
≥ 3.2
M8 1.25 12.57 – 13
16.34 – 18.4
5.92 – 6.5
≥ 11.5
5.5
≥ 4.1
M10 1.5 16.57 – 17
21.54 – 24
7.42 – 8
≥ 15.5
13
≥ 5.2
M12 1.75 18.48 – 19
24.02 – 26.9
9.42 – 10
≥ 17.2
19.1
≥ 6.6
M16 2 23.16 – 24
30.11 – 33.9
12.3 – 13
≥ 22
38.2
≥ 8.6
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 557
M5
s width across flats 7.64 – 8
e width across corners 9.93 – 11.3
m nut height 3.52 – 4
dw bearing face diameter ≥ 6.7
mass mass per 1000 pieces (kg) 1.31
mw height ≥ 2.5 Thread · ISO 261/262
Pitch P 0.8
d2 4.48
d3 4.019
Tap drill 4.2
Stress area As 14.18 mm² Size sheet · DIN 557
M6
s width across flats 9.64 – 10
e width across corners 12.53 – 14.1
m nut height 4.52 – 5
dw bearing face diameter ≥ 8.7
mass mass per 1000 pieces (kg) 2.77
mw height ≥ 3.2 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 557
M8
s width across flats 12.57 – 13
e width across corners 16.34 – 18.4
m nut height 5.92 – 6.5
dw bearing face diameter ≥ 11.5
mass mass per 1000 pieces (kg) 5.5
mw height ≥ 4.1 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 557
M10
s width across flats 16.57 – 17
e width across corners 21.54 – 24
m nut height 7.42 – 8
dw bearing face diameter ≥ 15.5
mass mass per 1000 pieces (kg) 13
mw height ≥ 5.2 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 557
M12
s width across flats 18.48 – 19
e width across corners 24.02 – 26.9
m nut height 9.42 – 10
dw bearing face diameter ≥ 17.2
mass mass per 1000 pieces (kg) 19.1
mw height ≥ 6.6 Thread · ISO 261/262
Pitch P 1.75
d2 10.863
d3 9.853
Tap drill 10.25
Stress area As 84.27 mm² Size sheet · DIN 557
M16
s width across flats 23.16 – 24
e width across corners 30.11 – 33.9
m nut height 12.3 – 13
dw bearing face diameter ≥ 22
mass mass per 1000 pieces (kg) 38.2
mw height ≥ 8.6 Thread · ISO 261/262
Pitch P 2
d2 14.701
d3 13.546
Tap drill 14
Stress area As 156.67 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.