Dimensions mm · values as the standard states them Size P dk k b da a r t n rt w X M1.6 0.35 3.2
2.9 – 3.2
1
0.86 – 1
≥ 25
≤ 2
≤ 0.7
≥ 0.1
≥ 0.35
0.4
0.46 – 0.6
(0.5)
≥ 0.3
≤ 0.9
M2 0.4 4
3.7 – 4
1.3
1.16 – 1.3
≥ 25
≤ 2.6
≤ 0.8
≥ 0.1
≥ 0.5
0.5
0.56 – 0.7
(0.6)
≥ 0.4
≤ 1
M2.5 0.45 5
4.7 – 5
1.5
1.36 – 1.5
≥ 25
≤ 3.1
≤ 0.9
≥ 0.1
≥ 0.6
0.6
0.66 – 0.8
(0.8)
≥ 0.5
≤ 1.1
M3 0.5 5.6
5.3 – 5.6
1.8
1.66 – 1.8
≥ 25
≤ 3.6
≤ 1
≥ 0.1
≥ 0.7
0.8
0.86 – 1
(0.9)
≥ 0.7
≤ 1.25
M4 0.7 8
7.64 – 8
2.4
2.26 – 2.4
≥ 38
≤ 4.7
≤ 1.4
≥ 0.2
≥ 1
1.2
1.26 – 1.51
(1.2)
≥ 1
≤ 1.75
M5 0.8 9.5
9.14 – 9.5
3
2.86 – 3
≥ 38
≤ 5.7
≤ 1.6
≥ 0.2
≥ 1.2
1.2
1.26 – 1.51
(1.5)
≥ 1.2
≤ 2
M6 1 12
11.57 – 12
3.6
3.3 – 3.6
≥ 38
≤ 6.8
≤ 2
≥ 0.25
≥ 1.4
1.6
1.66 – 1.91
(1.8)
≥ 1.4
≤ 2.5
M8 1.25 16
15.57 – 16
4.8
4.5 – 4.8
≥ 38
≤ 9.2
≤ 2.5
≥ 0.4
≥ 1.9
2
2.06 – 2.31
(2.4)
≥ 1.9
≤ 3.2
M10 1.5 20
19.48 – 20
6
5.7 – 6
≥ 38
≤ 11.2
≤ 3
≥ 0.4
≥ 2.4
2.5
2.56 – 2.81
(3)
≥ 2.4
≤ 3.8
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 2 1.8 – 2.2
2.5 2.3 – 2.7
3 2.8 – 3.2
4 3.76 – 4.24
5 4.76 – 5.24
6 5.76 – 6.24
8 7.71 – 8.29
10 9.71 – 10.29
12 11.65 – 12.35
14 13.65 – 14.35
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 54.05 – 55.95
60 59.05 – 60.95
65 64.05 – 65.95
70 69.05 – 70.95
75 74.05 – 75.95
80 79.05 – 80.95
Size sheet · ISO 1580
M1.6
dk head diameter 3.2
k head height 1
b thread length ≥ 25
da transition diameter ≤ 2
a length undercut ≤ 0.7
r fillet radius ≥ 0.1
t groove depth ≥ 0.35
n groove width 0.4
rt (0.5)
w ≥ 0.3
X ≤ 0.9 Thread · ISO 261/262
Pitch P 0.35
d2 1.373
d3 1.171
Tap drill 1.25
Stress area As 1.27 mm² Standard lengths
2 · 2.5 · 3 · 4 · 5 · 6 · 8 · 10 · 12 · 14 · 16
Size sheet · ISO 1580
M2
dk head diameter 4
k head height 1.3
b thread length ≥ 25
da transition diameter ≤ 2.6
a length undercut ≤ 0.8
r fillet radius ≥ 0.1
t groove depth ≥ 0.5
n groove width 0.5
rt (0.6)
w ≥ 0.4
X ≤ 1 Thread · ISO 261/262
Pitch P 0.4
d2 1.74
d3 1.509
Tap drill 1.6
Stress area As 2.07 mm² Standard lengths
2.5 · 3 · 4 · 5 · 6 · 8 · 10 · 12 · 14 · 16 · 20
Size sheet · ISO 1580
M2.5
dk head diameter 5
k head height 1.5
b thread length ≥ 25
da transition diameter ≤ 3.1
a length undercut ≤ 0.9
r fillet radius ≥ 0.1
t groove depth ≥ 0.6
n groove width 0.6
rt (0.8)
w ≥ 0.5
X ≤ 1.1 Thread · ISO 261/262
Pitch P 0.45
d2 2.208
d3 1.948
Tap drill 2.05
Stress area As 3.39 mm² Standard lengths
3 · 4 · 5 · 6 · 8 · 10 · 12 · 14 · 16 · 20 · 25
Size sheet · ISO 1580
M3
dk head diameter 5.6
k head height 1.8
b thread length ≥ 25
da transition diameter ≤ 3.6
a length undercut ≤ 1
r fillet radius ≥ 0.1
t groove depth ≥ 0.7
n groove width 0.8
rt (0.9)
w ≥ 0.7
X ≤ 1.25 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
4 · 5 · 6 · 8 · 10 · 12 · 14 · 16 · 20 · 25 · 30
Size sheet · ISO 1580
M4
dk head diameter 8
k head height 2.4
b thread length ≥ 38
da transition diameter ≤ 4.7
a length undercut ≤ 1.4
r fillet radius ≥ 0.2
t groove depth ≥ 1
n groove width 1.2
rt (1.2)
w ≥ 1
X ≤ 1.75 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
5 · 6 · 8 · 10 · 12 · 14 · 16 · 20 · 25 · 30 · 35 · 40
Size sheet · ISO 1580
M5
dk head diameter 9.5
k head height 3
b thread length ≥ 38
da transition diameter ≤ 5.7
a length undercut ≤ 1.6
r fillet radius ≥ 0.2
t groove depth ≥ 1.2
n groove width 1.2
rt (1.5)
w ≥ 1.2
X ≤ 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
6 · 8 · 10 · 12 · 14 · 16 · 20 · 25 · 30 · 35 · 40 · 45 · 50
Size sheet · ISO 1580
M6
dk head diameter 12
k head height 3.6
b thread length ≥ 38
da transition diameter ≤ 6.8
a length undercut ≤ 2
r fillet radius ≥ 0.25
t groove depth ≥ 1.4
n groove width 1.6
rt (1.8)
w ≥ 1.4
X ≤ 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 · 14 · 16 · 20 · 25 · 30 · 35 · 40 · 45 · 50 · 55 · 60
Size sheet · ISO 1580
M8
dk head diameter 16
k head height 4.8
b thread length ≥ 38
da transition diameter ≤ 9.2
a length undercut ≤ 2.5
r fillet radius ≥ 0.4
t groove depth ≥ 1.9
n groove width 2
rt (2.4)
w ≥ 1.9
X ≤ 3.2 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 · 14 · 16 · 20 · 25 · 30 · 35 · 40 · 45 · 50 · 55 · 60 · 65 · 70 · 75 · 80
Size sheet · ISO 1580
M10
dk head diameter 20
k head height 6
b thread length ≥ 38
da transition diameter ≤ 11.2
a length undercut ≤ 3
r fillet radius ≥ 0.4
t groove depth ≥ 2.4
n groove width 2.5
rt (3)
w ≥ 2.4
X ≤ 3.8 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 · 14 · 16 · 20 · 25 · 30 · 35 · 40 · 45 · 50 · 55 · 60 · 65 · 70 · 75 · 80
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 (2) Dimensions cross-checked against the official ISO 1580:2011 preview — values match. The source publishes one identical table for DIN 85, ISO 1580.