| Thread | Drill size for tapping standard metric threads | Clearance hole |
| M1 | 0.75 | 1.2 |
| M1.2 | 0.95 | 1.4 |
| M1.4 | 1.1 | 1.6 |
| M1.6 | 1.5 | 1.8 |
| M1.8 | 1.4 | 2 |
| M2 | 1.6 | 2.4 |
| M2.2 | 1.7 | 2.8 |
| M2.5 | 2 | 2.9 |
| M3 | 2.5 | 3.4 |
| M3.5 | 2.9 | 3.9 |
| M4 | 3.3 | 4.5 |
| M5 | 4.2 | 5.5 |
| M6 | 5 | 6.6 |
| M8 | 6.8 | 9 |
| M10 | 8.5 | 11 |
| M12 | 10.2 | 13.5 |
| M14 | 12 | 15.5 |
| M16 | 14 | 17.5 |
| M18 | 15.5 | 20 |
| M20 | 17.5 | 22 |
| M22 | 19.5 | 24 |
| M24 | 21 | 26 |
| M27 | 24 | 30 |
| M30 | 26.5 | 33 |