The table below is a guide to show metric equivalents of common Imperial screw gauges. The table contains data on Head diameter and Countersink drill size, Shank diameter and Clearance drill size, Pilot hole sizes for Timber, Rawlplug colours and Masonry drill sizes
| Imperial | Metric | Screw | Screw Head | Screw | Screw Shank | Softwood | Hardwood | Masonry | |
| Screw | Screw | Head Dia | Countersink | Shank Dia | Clearance | Pilot Dia | Pilot Dia | Plug | Drill |
| Gauge No. | Guage mm | mm | Drill mm | mm | Drill mm | mm | mm | Colour | mm |
| 2 | 2 | 4.36 | 6.0 | 2.38 | 2.5 | 1.5 | 1.5 | ||
| 3 | 2.5 | 5.16 | 6.0 | 2.77 | 3.0 | 1.5 | 1.5 | Yellow | 5 |
| 4 | 3 | 5.95 | 6.0 | 2.77 | 3.0 | 1.5 | 2.0 | Yellow | 5 |
| 6 | 3.5 | 7.14 | 8.0 | 3.57 | 4.0 | 2.0 | 2.5 | Red | 6 |
| 8 | 4 | 8.73 | 9.0 | 3.97 | 4.5 | 2.5 | 3.0 | Red/Brown | 6 or 7 |
| 10 | 5 | 9.92 | 10.0 | 4.76 | 5.5 | 3.0 | 3.0 | Brown | 7 |
| 12 | 5.5 | 11.11 | 11.0 | 5.55 | 6.5 | 3.0 | 3.5 | Brown | 7 |
| 14 | 6.5 | 12.70 | 12.0 | 6.35 | 7.0 | 3.5 | 4.0 | Blue | 10 |