METRIC TAP DRILL CHART

Metric tap drill chart according to ISO 2306 standard for ISO metric threads. Dimensions are in millimetres.

Metric Tap Drill Chart - Coarse Thread
Coarse Pitch Thread Drill size (mm)
Tap Size Basic Major
Dia.		 Thread Pitch Minor diameter for class
5H max. 6H max. 7H max. 5H, 6H, 7H min
M1.6 x 0.35 1.6 0.35 1.301 1.321 - 1.221 1.25
M2 x 0.4 2 0.4 1.657 1.679 - 1.567 1.60
M2.5 x 0.45 2.5 0.45 2.113 2.138 - 2.013 2.05
M3 x 0.5 3 0.5 2.571 2.599 2.639 2.459 2.50
M3.5* x 0.6 3.5 0.6 2.975 3.010 3.050 2.850 2.90
M4 x 0.7 4 0.7 3.382 3.422 3.466 3.242 3.30
M5 x 0.8 5 0.8 4.294 4.334 4.384 4.134 4.20
M6 x 1 6 1 5.107 5.153 5.217 4.917 5.00
M8 x 1.25 8 1.25 6.859 6.912 6.982 6.647 6.80
M10 x 1.5 10 1.5 8.612 8.676 8.751 8.376 8.50
Coarse Pitch Thread Drill size (mm)
Tap Size Basic Major
Dia.		 Thread Pitch Minor diameter for class
5H max. 6H max. 7H max. 5H, 6H, 7H min
M12 x 1.75 12 1.75 10.371 10.441 10.531 10.106 10.20
M14* x 2 14 2 12.135 12.210 12.310 11.835 12.00
M16 x 2 16 2 14.135 14.210 14.310 13.835 14.00
M18* x 2.5 18 2.5 15.649 15.744 15.854 15.294 15.50
M20 x 2.5 20 2.5 17.649 17.744 17.854 17.294 17.50
M22* x 2.5 22 2.5 19.649 19.744 19.854 19.294 19.50
M24 x 3 24 3 21.152 21.252 21.382 20.752 21.00
M27* x 3 27 3 24.152 24.252 24.382 23.752 24.00
M30 x 3.5 30 3.5 26.661 26.771 26.921 26.211 26.50
Coarse Pitch Thread Drill size (mm)
Tap Size Basic Major
Dia.		 Thread Pitch Minor diameter for class
5H max. 6H max. 7H max. 5H, 6H, 7H min
M33* x 3.5 33 3.5 29.661 29.771 29.921 29.211 29.50
M36 x 4 36 4 32.145 32.270 32.420 31.670 32.00
M39* x 4 39 4 35.145 35.270 35.420 34.670 35.00
M42 x 4.5 42 4.5 37.659 37.799 37.979 37.129 37.50
M45* x 4.5 45 4.5 40.659 40.799 40.979 40.129 40.50
M48 x 5 48 5 43.147 43.297 43.487 42.587 43.00
M52* x 5 52 5 47.147 47.297 47.487 46.587 47.00
M56 x 5.5 56 5.5 50.646 50.796 50.996 50.046 50.50

Note : * Non-preferred threads according to standard.


Metric Tap Drill Chart - Fine Thread
Fine Pitch Thread Drill size (mm)
Tap Size Basic Major
Dia.		 Thread Pitch Minor diameter for class
5H max. 6H max. 7H max. 5H, 6H, 7H min
M8 x 1 8 1 7.107 7.153 7.217 6.917 7.00
M10 x 1 10 1 9.107 9.153 9.217 8.917 9.00
M10* x 1.25 10 1.25 8.859 8.912 8.982 8.647 8.80
M12* x 1.25 12 1.25 10.859 10.912 10.982 10.647 10.80
M12 x 1.5 12 1.5 10.612 10.676 10.751 10.376 10.50
M14* x 1.5 14 1.5 12.612 12.676 12.751 12.376 12.50
M16 x 1.5 16 1.5 14.612 14.676 14.751 14.376 14.50
M18* x 1.5 18 1.5 16.612 16.676 16.751 16.376 16.50
M20 x 1.5 20 1.5 18.612 18.676 18.751 18.376 18.50
M20* x 2 20 2 18.135 18.210 18.310 17.835 18.00
Coarse Pitch Thread Drill size (mm)
Tap Size Basic Major
Dia.		 Thread Pitch Minor diameter for class
5H max. 6H max. 7H max. 5H, 6H, 7H min
M22* x 1.5 22 1.5 20.612 20.676 20.751 20.376 20.50
M24 x 2 24 2 22.135 22.210 22.310 21.835 22.00
M27* x 2 27 2 25.135 25.210 25.310 24.835 25.00
M30 x 2 30 2 28.135 28.210 28.310 27.835 28.00
M33* x 2 33 2 31.135 31.210 31.310 30.835 31.00
M36 x 3 36 3 33.152 33.252 33.382 32.752 33.00
M39* x 3 39 3 36.152 36.252 36.382 36.752 36.00
M42 x 3 42 3 39.152 39.252 39.382 38.752 39.00
M45* x 3 45 3 42.152 42.252 42.382 41.752 42.00
M48 x 3 48 3 45.152 45.252 45.382 44.752 45.00
M52* x 4 52 4 48.145 48.270 48.420 47.670 48.00

Note : * Non-preferred threads according to standard.

Supplements:

Reference:

  • ISO 68-1:1998(E) - ISO general purpose screw threads — Basic profile — Part 1: Metric screw threads
  • ISO 2306:1972, Drills for use prior to tapping screw threads