Home › Metric tap drill chart
Metric tap drill chart
Metric tap drill = nominal diameter − pitch. An M8 × 1.25 tap needs a 6.8 mm drill.
ISO metric coarse threads
| Thread | Pitch (mm) | Tap drill (mm) | Inch drill alt. | Clearance (medium) |
|---|---|---|---|---|
| M1.6 x 0.35 | 0.35 | 1.25 | 3/64 | 1.8 mm |
| M2 x 0.4 | 0.4 | 1.6 | #52 | 2.4 mm |
| M2.5 x 0.45 | 0.45 | 2.05 | #46 | 2.9 mm |
| M3 x 0.5 | 0.5 | 2.5 | #40 | 3.4 mm |
| M3.5 x 0.6 | 0.6 | 2.9 | #33 | 3.9 mm |
| M4 x 0.7 | 0.7 | 3.3 | #30 | 4.5 mm |
| M5 x 0.8 | 0.8 | 4.2 | #19 | 5.5 mm |
| M6 x 1 | 1 | 5 | #9 | 6.6 mm |
| M8 x 1.25 | 1.25 | 6.8 | H | 9 mm |
| M10 x 1.5 | 1.5 | 8.5 | Q | 11 mm |
| M12 x 1.75 | 1.75 | 10.2 | Y | 13.5 mm |
| M14 x 2 | 2 | 12 | 15/32 | 15.5 mm |
| M16 x 2 | 2 | 14 | 35/64 | 17.5 mm |
| M18 x 2.5 | 2.5 | 15.5 | 39/64 | 20 mm |
| M20 x 2.5 | 2.5 | 17.5 | 11/16 | 22 mm |
| M22 x 2.5 | 2.5 | 19.5 | 49/64 | 24 mm |
| M24 x 3 | 3 | 21 | 53/64 | 26 mm |
| M27 x 3 | 3 | 24 | 15/16 | 30 mm |
| M30 x 3.5 | 3.5 | 26.5 | 1 in | 33 mm |
ISO metric fine threads
| Thread | Pitch (mm) | Tap drill (mm) | Inch drill alt. | Clearance (medium) |
|---|---|---|---|---|
| M8 x 1 | 1 | 7 | J | 9 mm |
| M10 x 1.25 | 1.25 | 8.8 | S | 11 mm |
| M10 x 1 | 1 | 9 | T | 11 mm |
| M12 x 1.5 | 1.5 | 10.5 | Z | 13.5 mm |
| M12 x 1.25 | 1.25 | 10.8 | 27/64 | 13.5 mm |
| M14 x 1.5 | 1.5 | 12.5 | 31/64 | 15.5 mm |
| M16 x 1.5 | 1.5 | 14.5 | 37/64 | 17.5 mm |
| M18 x 1.5 | 1.5 | 16.5 | 21/32 | 20 mm |
| M20 x 1.5 | 1.5 | 18.5 | 47/64 | 22 mm |
| M22 x 1.5 | 1.5 | 20.5 | 13/16 | 24 mm |
| M24 x 2 | 2 | 22 | 55/64 | 26 mm |