Hole sizes for the machine making the part
All sizes

Metric clearance hole chart - close, normal & free

Close, normal and free clearance-hole diameters for every metric screw size in the catalog, M1.6-0.35 to M24-3.0. Normal is the everyday choice; the last column gives it in inches too. Cutting threads instead? See the metric tap drill chart. Tap any size for its full page - heat-set pockets, nut pockets and 3D-printing numbers.

SizeClose (mm)Normal (mm)Free (mm)Normal in inches
M1.6-0.351.71.82= 0.0709 in
M2-0.42.22.42.6= 0.0945 in
M2.5-0.452.72.93.1= 0.1142 in
M3-0.53.23.43.6= 0.1339 in
M3.5-0.63.73.94.2= 0.1535 in
M4-0.74.34.54.8= 0.1772 in
M5-0.55.35.55.8= 0.2165 in
M5-0.85.35.55.8= 0.2165 in
M6-0.756.46.67= 0.2598 in
M6-1.06.46.67= 0.2598 in
M8-1.08.4910= 0.3543 in
M8-1.258.4910= 0.3543 in
M10-1.010.51112= 0.4331 in
M10-1.2510.51112= 0.4331 in
M10-1.510.51112= 0.4331 in
M12-1.251313.514.5= 0.5315 in
M12-1.51313.514.5= 0.5315 in
M12-1.751313.514.5= 0.5315 in
M14-1.51515.516.5= 0.6102 in
M14-2.01515.516.5= 0.6102 in
M16-1.51717.518.5= 0.689 in
M16-2.01717.518.5= 0.689 in
M18-1.5192021= 0.7874 in
M18-2.5192021= 0.7874 in
M20-1.5212224= 0.8661 in
M20-2.5212224= 0.8661 in
M22-2.5242526= 0.9843 in
M24-2.0252628= 1.0236 in
M24-3.0252628= 1.0236 in
All values mm; Normal is the everyday clearance. 3D printing? Add your slicer's hole compensation on top - each size's page shows it. Tap drill sizes are on the <a href="/charts/metric-tap-drill/">metric tap drill chart</a>.
These are standard reference numbers. Every machine prints and cuts a little differently - set a hole to Ø5.00 and it might land at Ø4.95. In the FitCheck app you calibrate your machine, and the clearance and pocket diameters here shift to match it - plus tolerance bands and full offline use.
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Metric and imperial clearances follow published mechanical-engineering references · heat-set pockets per CNC Kitchen · bearing housing seats follow published fit tables. Reference only - verify before you cut.