Shop reference tools
Metric Tap Drill Chart
Reference metric tap drill sizes for M3 through M12 coarse threads.
Metric Tap Drill Chart lookup
Start with the table, then use the related pages for tapping, clearance holes, pilot holes, and printable shop sheets.
| Thread | Tap drill | Decimal inch | Millimeters | Working note |
|---|---|---|---|---|
| M3 x 0.5 | 2.5 mm | 0.0984 | 2.50 | Approximate metric tap drill: major diameter minus pitch. |
| M4 x 0.7 | 3.3 mm | 0.1299 | 3.30 | Use published chart for production work. |
| M5 x 0.8 | 4.2 mm | 0.1654 | 4.20 | Common metric coarse thread. |
| M6 x 1 | 5.0 mm | 0.1969 | 5.00 | Common metric coarse thread. |
| M8 x 1.25 | 6.8 mm | 0.2677 | 6.80 | Common metric coarse thread. |
| M10 x 1.5 | 8.5 mm | 0.3346 | 8.50 | Common metric coarse thread. |
| M12 x 1.75 | 10.2 mm | 0.4016 | 10.20 | Common metric coarse thread. |