Dimensions mm · values as the standard states them Size P s e dw da c r dc m´ thread_alt M5 0.8 8
7.78 – 8
≥ 8.79
≥ 9.8
5 – 5.75
≥ 1
≤ 0.3
≤ 11.8
≥ 2.2
—
M6 1 10
9.78 – 10
≥ 11.05
≥ 12.2
6 – 6.75
≥ 1.1
≤ 0.36
≤ 14.2
≥ 3.1
—
M8 1.25 13
12.73 – 13
≥ 14.38
≥ 15.8
8 – 8.75
≥ 1.2
≤ 0.48
≤ 17.9
≥ 4.5
M8x1
M10 1.5 15
14.73 – 15
≥ 16.64
≥ 19.6
10 – 10.8
≥ 1.5
≤ 0.6
≤ 21.8
≥ 5.5
(M10x1)
M12 1.75 18
17.73 – 18
≥ 20.03
≥ 23.8
12 – 13
≥ 1.8
≤ 0.72
≤ 26
≥ 6.7
(M12x1,5)
M14 2 21
20.67 – 21
≥ 23.36
≥ 27.6
14 – 15.1
≥ 2.1
≤ 0.88
≤ 29.9
≥ 7.8
M14x1,5
M16 2 24
23.67 – 24
≥ 26.75
≥ 31.9
16 – 17.3
≥ 2.4
≤ 0.96
≤ 34.5
≥ 9
M16x1,5
M20 2.5 30
29.67 – 30
≥ 32.95
≥ 39.9
20 – 21.6
≥ 3
≤ 1.2
≤ 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.
Size sheet · ISO 4161
M5
s width across flats 8
e width across corners ≥ 8.79
dw bearing face diameter ≥ 9.8
da transition diameter 5 – 5.75
c ≥ 1
r radius ≤ 0.3
dc outer diameter of the ring ≤ 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 Size sheet · ISO 4161
M6
s width across flats 10
e width across corners ≥ 11.05
dw bearing face diameter ≥ 12.2
da transition diameter 6 – 6.75
c ≥ 1.1
r radius ≤ 0.36
dc outer diameter of the ring ≤ 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 Size sheet · ISO 4161
M8
s width across flats 13
e width across corners ≥ 14.38
dw bearing face diameter ≥ 15.8
da transition diameter 8 – 8.75
c ≥ 1.2
r radius ≤ 0.48
dc outer diameter of the ring ≤ 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 Size sheet · ISO 4161
M10
s width across flats 15
e width across corners ≥ 16.64
dw bearing face diameter ≥ 19.6
da transition diameter 10 – 10.8
c ≥ 1.5
r radius ≤ 0.6
dc outer diameter of the ring ≤ 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 Size sheet · ISO 4161
M12
s width across flats 18
e width across corners ≥ 20.03
dw bearing face diameter ≥ 23.8
da transition diameter 12 – 13
c ≥ 1.8
r radius ≤ 0.72
dc outer diameter of the ring ≤ 26
m´ ≥ 6.7
thread_alt alternative / fine thread (M12x1,5) 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 · ISO 4161
M14
s width across flats 21
e width across corners ≥ 23.36
dw bearing face diameter ≥ 27.6
da transition diameter 14 – 15.1
c ≥ 2.1
r radius ≤ 0.88
dc outer diameter of the ring ≤ 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 Size sheet · ISO 4161
M16
s width across flats 24
e width across corners ≥ 26.75
dw bearing face diameter ≥ 31.9
da transition diameter 16 – 17.3
c ≥ 2.4
r radius ≤ 0.96
dc outer diameter of the ring ≤ 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 Size sheet · ISO 4161
M20
s width across flats 30
e width across corners ≥ 32.95
dw bearing face diameter ≥ 39.9
da transition diameter 20 – 21.6
c ≥ 3
r radius ≤ 1.2
dc outer diameter of the ring ≤ 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 Provenance
Reviewed — dimensions cross-checked against the official ISO preview; values match.
Accessed 2026-09-23 · For design and safety-critical use, consult the current edition of the standard.
Data notes (3) Dimensions cross-checked against the official ISO 4161:1999 preview — values match. Parameters that did not match the current ISO edition were omitted: m. The source publishes one identical table for DIN 6923, ISO 4161.