Metric clearance hole chart for metric bolts and screws according to ASME B18.2.8
M2 Clearance Hole :
Close fit: 2.2 mm, Normal fit: 2.4 mm , Loose fit: 2.6 mm
M3 Clearance Hole :
Close fit: 3.2 mm, Normal fit: 3.4 mm , Loose fit: 3.6 mm
M4 Clearance Hole :
Close fit: 4.3 mm, Normal fit: 4.5 mm , Loose fit: 4.8 mm
M5 Clearance Hole :
Close fit: 5.3 mm, Normal fit: 5.5 mm , Loose fit: 5.8 mm
M6 Clearance Hole :
Close fit: 6.4 mm, Normal fit: 6.6 mm , Loose fit: 7 mm
M8 Clearance Hole :
Close fit: 8.4 mm, Normal fit: 9 mm , Loose fit: 10 mm
M10 Clearance Hole :
Close fit: 10.5 mm, Normal fit: 11 mm , Loose fit: 12 mm
M12 Clearance Hole :
Close fit: 13 mm, Normal fit: 13.5 mm , Loose fit: 14.5 mm