METRIC CLEARANCE HOLE CHART

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

Metric Clearance Holes Chart
Nominal Screw Size Fit Class - Normal Fit Class - Close Fit Class - Loose
Nominal Drill Size Hole Diameter Nominal Drill Size Hole Diameter Nominal Drill Size Hole Diameter
Min. Max. Min. Max. Min. Max.
M1.6 1.8 1.8 1.94 1.7 1.7 1.8 2 2 2.25
M2  2.4 2.4 2.54 2.2 2.2 2.3 2.6 2.6 2.85
M2.5 2.9 2.9 3.04 2.7 2.7 2.8 3.1 3.1 3.4
M3 3.4 3.4 3.58 3.2 3.2 3.32 3.6 3.6 3.9
M4 4.5 4.5 4.68 4.3 4.3 4.42 4.8 4.8 5.1
M5 5.5 5.5 5.68 5.3 5.3 5.42 5.8 5.8 6.1
M6 6.6 6.6 6.82 6.4 6.4 6.55 7 7 7.36
M8 9 9 9.22 8.4 8.4 8.55 10 10 10.36
M10 11 11 11.27 10.5 10.5 10.68 12 12 12.43
Nominal Screw Size Fit Class - Normal Fit Class - Close Fit Class - Loose
Nominal Drill Size Hole Diameter Nominal Drill Size Hole Diameter Nominal Drill Size Hole Diameter
Min. Max. Min. Max. Min. Max.
M12 13.5 13.5 13.77 13 13 13.18 14.5 14.5 14.93
M14 15.5 15.5 15.77 15 15 15.18 16.5 16.5 16.93
M16 17.5 17.5 17.77 17 17 17.18 18.5 18.5 19.02
M20 22 22 22.33 21 21 21.21 24 24 24.52
M24 26 26 26.33 25 25 25.21 28 28 28.52
M30 33 33 33.39 31 31 31.25 35 35 35.62
M36 39 39 39.39 37 37 37.25 42 42 42.62
M42 45 45 45.39 43 43 43.25 48 48 48.62
M48 52 52 52.46 50 50 50.25 56 56 56.74
Nominal Screw Size Fit Class - Normal Fit Class - Close Fit Class - Loose
Nominal Drill Size Hole Diameter Nominal Drill Size Hole Diameter Nominal Drill Size Hole Diameter
Min. Max. Min. Max. Min. Max.
M56 62 62 62.46 58 58 58.3 66 66 66.74
M64 70 70 70.46 66 66 66.3 74 74 74.74
M72 78 78 78.46 74 74 74.3 82 82 82.87
M80 86 86 86.54 82 82 82.35 91 91 91.87
M90 96 96 96.54 93 93 93.35 101 101 101.87
M100 107 107 107.54 104 104 104.35 112 112 112.87

Supplements:

Reference:

  • Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2016) . Machinery's Handbook . 30th edition.  Industrial Press Inc.
  • Oberg, E. , Jones ,F.D. , Horton H.L. , Ryffel H.H., (2012) . Machinery's Handbook . 29th edition.  Industrial Press Inc.
  • ASME B18.2.8-1999, Clearance holes for bolts, screws and studs