Dimensions mm · values as the standard states them Size P dk k b da a r t hexalobular A hexalobular recess_no hexalobular rf x M2 0.4 4
3.7 – 4
1.6
1.46 – 1.6
≥ 25
≤ 2.6
≤ 0.8
≥ 0.1
0.63 – 0.77
(1.75)
6
≈ 3.2
≤ 1
M2.5 0.45 5
4.7 – 5
2.1
1.96 – 2.1
≥ 25
≤ 3.1
≤ 0.9
≥ 0.1
0.91 – 1.04
(2.4)
8
≈ 4
≤ 1.1
M3 0.5 5.6
5.3 – 5.6
2.4
2.26 – 2.4
≥ 25
≤ 3.6
≤ 1
≥ 0.1
1.01 – 1.27
(2.8)
10
≈ 5
≤ 1.25
M3.5 0.6 7
6.64 – 7
2.6
2.46 – 2.6
≥ 38
≤ 4.1
≤ 1.2
≥ 0.1
1.07 – 1.33
(3.35)
15
≈ 6
≤ 1.5
M4 0.7 8
7.64 – 8
3.1
2.92 – 3.1
≥ 38
≤ 4.7
≤ 1.4
≥ 0.2
1.27 – 1.66
(3.95)
20
≈ 6.5
≤ 1.75
M5 0.8 9.5
9.14 – 9.5
3.7
3.52 – 3.7
≥ 38
≤ 5.7
≤ 1.6
≥ 0.2
1.52 – 1.91
(4.5)
25
≈ 8
≤ 2
M6 1 12
11.57 – 12
4.6
4.3 – 4.6
≥ 38
≤ 6.8
≤ 2
≥ 0.25
2.02 – 2.42
(5.6)
30
≈ 10
≤ 2.5
M8 1.25 16
15.57 – 16
6
5.7 – 6
≥ 38
≤ 9.2
≤ 2.5
≥ 0.4
2.79 – 3.18
(7.95)
45
≈ 13
≤ 3.2
M10 1.5 20
19.48 – 20
7.5
7.14 – 7.5
≥ 38
≤ 11.2
≤ 3
≥ 0.4
3.62 – 4.02
(8.95)
50
≈ 16
≤ 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 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 54.4 – 55.6
60 59.4 – 60.6
Size sheet · ISO 14583
M2
dk head diameter 4
k head height 1.6
b thread length ≥ 25
da transition diameter ≤ 2.6
a ≤ 0.8
r fillet radius ≥ 0.1
t groove depth (hexalobular) 0.63 – 0.77
A groove (hexalobular) (1.75)
recess_no drive size (hexalobular) 6
rf ≈ 3.2
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
3 · 4 · 5 · 6 · 8 · 10 · 12 · 14 · 16 · 20
Size sheet · ISO 14583
M2.5
dk head diameter 5
k head height 2.1
b thread length ≥ 25
da transition diameter ≤ 3.1
a ≤ 0.9
r fillet radius ≥ 0.1
t groove depth (hexalobular) 0.91 – 1.04
A groove (hexalobular) (2.4)
recess_no drive size (hexalobular) 8
rf ≈ 4
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 14583
M3
dk head diameter 5.6
k head height 2.4
b thread length ≥ 25
da transition diameter ≤ 3.6
a ≤ 1
r fillet radius ≥ 0.1
t groove depth (hexalobular) 1.01 – 1.27
A groove (hexalobular) (2.8)
recess_no drive size (hexalobular) 10
rf ≈ 5
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 14583
M3.5
dk head diameter 7
k head height 2.6
b thread length ≥ 38
da transition diameter ≤ 4.1
a ≤ 1.2
r fillet radius ≥ 0.1
t groove depth (hexalobular) 1.07 – 1.33
A groove (hexalobular) (3.35)
recess_no drive size (hexalobular) 15
rf ≈ 6
x ≤ 1.5 Thread · ISO 261/262
Pitch P 0.6
d2 3.11
d3 2.764
Tap drill 2.9
Stress area As 6.78 mm² Standard lengths
5 · 6 · 8 · 10 · 12 · 14 · 16 · 20 · 25 · 30 · 35
Size sheet · ISO 14583
M4
dk head diameter 8
k head height 3.1
b thread length ≥ 38
da transition diameter ≤ 4.7
a ≤ 1.4
r fillet radius ≥ 0.2
t groove depth (hexalobular) 1.27 – 1.66
A groove (hexalobular) (3.95)
recess_no drive size (hexalobular) 20
rf ≈ 6.5
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 14583
M5
dk head diameter 9.5
k head height 3.7
b thread length ≥ 38
da transition diameter ≤ 5.7
a ≤ 1.6
r fillet radius ≥ 0.2
t groove depth (hexalobular) 1.52 – 1.91
A groove (hexalobular) (4.5)
recess_no drive size (hexalobular) 25
rf ≈ 8
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 14583
M6
dk head diameter 12
k head height 4.6
b thread length ≥ 38
da transition diameter ≤ 6.8
a ≤ 2
r fillet radius ≥ 0.25
t groove depth (hexalobular) 2.02 – 2.42
A groove (hexalobular) (5.6)
recess_no drive size (hexalobular) 30
rf ≈ 10
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 14583
M8
dk head diameter 16
k head height 6
b thread length ≥ 38
da transition diameter ≤ 9.2
a ≤ 2.5
r fillet radius ≥ 0.4
t groove depth (hexalobular) 2.79 – 3.18
A groove (hexalobular) (7.95)
recess_no drive size (hexalobular) 45
rf ≈ 13
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
Size sheet · ISO 14583
M10
dk head diameter 20
k head height 7.5
b thread length ≥ 38
da transition diameter ≤ 11.2
a ≤ 3
r fillet radius ≥ 0.4
t groove depth (hexalobular) 3.62 – 4.02
A groove (hexalobular) (8.95)
recess_no drive size (hexalobular) 50
rf ≈ 16
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
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 (1) Dimensions cross-checked against the official ISO 14583:2011 preview — values match.