Dimensions of Metric Hex Nuts
Metric Hex Nuts         
Metric Hex Nuts
ISO 4032
Nominal Size Thread 
Pitch
F G H
Width Across Flats
(Wrench Size)
Width 
Across 
Corners
Thickness
Max Min Min Max Min
M1.6 0.35 3.2 3.02 3.41 1.3 1.05
M2 0.4 4 3.82 4.32 1.6 1.35
M2.5 0.45 5 4.82 5.45 2 1.75
M3 0.5 5.5 5.32 6.01 2.4 2.15
M4 0.7 7 6.78 7.66 3.2 2.9
M5 0.8 8 7.78 8.79 4.7 4.4
M6 1 10 9.78 11.05 5.2 4.9
M8 1.25 13 12.73 14.38 6.8 6.44
M10 1.5 16 15.73 17.77 8.4 8.04
M12 1.75 18 17.73 20.03 10.8 10.37
M14 2 21 20.67 23.35 12.8 12.1
M16 2 24 23.67 26.75 14.8 14.1
M20 2.5 30 29.16 32.95 18 16.9
M24 3 36 35 39.55 21.5 20.2
M30 3.5 46 45 50.85 25.6 24.3
M36 4 55 53.8 60.78 31 29.4
M42 4.5 65 63.1 71.3 34 32.4
M48 5 75 73.1 82.6 38 36.4
M56 5.5 85 82.8 93.56 45 43.4
M64 6 95 92.8 104.86 51 49.1