Letter Sizes of Drills
This table shows drill letter diameter (gauge) sizes from A to Z in Millimeters and Inches.
| Drill | Millimeter (mm) | Inch (in) |
|---|---|---|
| A | 5.94 | 0.23 |
| B | 6.05 | 0.24 |
| C | 6.15 | 0.24 |
| D | 6.25 | 0.25 |
| E | 6.35 | 0.25 |
| F | 6.53 | 0.26 |
| G | 6.63 | 0.26 |
| H | 6.76 | 0.27 |
| I | 6.91 | 0.27 |
| J | 7.04 | 0.28 |
| K | 7.14 | 0.28 |
| L | 7.37 | 0.29 |
| M | 7.49 | 0.29 |
| N | 7.67 | 0.30 |
| O | 8.03 | 0.32 |
| P | 8.20 | 0.32 |
| Q | 8.43 | 0.33 |
| R | 8.61 | 0.34 |
| S | 8.84 | 0.35 |
| T | 9.09 | 0.36 |
| U | 9.35 | 0.37 |
| V | 9.58 | 0.38 |
| W | 9.80 | 0.39 |
| X | 10.08 | 0.40 |
| Y | 10.26 | 0.40 |
| Z | 10.49 | 0.41 |
Note: The drill sizes are based on the ANSI B94.11M-1979 standard. The data in this table is correct to 2 decimal places.
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