Dimensions mm · values as the standard states them Size P dk m k b da a r x M2.5 0.45 ≤ 4.5
1
≤ 1.8
≥ 25
≤ 3.1
≤ 0.9
≥ 0.1
≤ 1.1
M3 0.5 ≤ 5.5
2
≤ 2
≥ 25
≤ 3.6
≤ 1
≥ 0.1
≤ 1.25
M4 0.7 ≤ 7
2
≤ 2.6
≥ 38
≤ 4.7
≤ 1.4
≥ 0.2
≤ 1.75
M5 0.8 ≤ 8.5
2
≤ 3.3
≥ 38
≤ 5.7
≤ 1.6
≥ 0.2
≤ 2
M6 1 ≤ 10
3
≤ 3.9
≥ 38
≤ 6.8
≤ 2
≥ 0.25
≤ 2.5
M8 1.25 ≤ 13
3
≤ 5
≥ 38
≤ 9.2
≤ 2.5
≥ 0.4
≤ 3.2
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 7048
M2.5
dk head diameter ≤ 4.5
m groove width 1
k head height ≤ 1.8
b thread length ≥ 25
da transition diameter ≤ 3.1
a length undercut ≤ 0.9
r fillet radius ≥ 0.1
x thread run ≤ 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 Size sheet · ISO 7048
M3
dk head diameter ≤ 5.5
m groove width 2
k head height ≤ 2
b thread length ≥ 25
da transition diameter ≤ 3.6
a length undercut ≤ 1
r fillet radius ≥ 0.1
x thread run ≤ 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 Size sheet · ISO 7048
M4
dk head diameter ≤ 7
m groove width 2
k head height ≤ 2.6
b thread length ≥ 38
da transition diameter ≤ 4.7
a length undercut ≤ 1.4
r fillet radius ≥ 0.2
x thread run ≤ 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 Size sheet · ISO 7048
M5
dk head diameter ≤ 8.5
m groove width 2
k head height ≤ 3.3
b thread length ≥ 38
da transition diameter ≤ 5.7
a length undercut ≤ 1.6
r fillet radius ≥ 0.2
x thread run ≤ 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 7048
M6
dk head diameter ≤ 10
m groove width 3
k head height ≤ 3.9
b thread length ≥ 38
da transition diameter ≤ 6.8
a length undercut ≤ 2
r fillet radius ≥ 0.25
x thread run ≤ 2.5 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 7048
M8
dk head diameter ≤ 13
m groove width 3
k head height ≤ 5
b thread length ≥ 38
da transition diameter ≤ 9.2
a length undercut ≤ 2.5
r fillet radius ≥ 0.4
x thread run ≤ 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 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 7048:2011 preview — values match.