Shop reference tools
Drill Size Chart
Find fractional, number, letter, and metric drill sizes with decimal inch and millimeter equivalents.
Drill Size Chart lookup
Start with the table, then use the related pages for tapping, clearance holes, pilot holes, and printable shop sheets.
| Size | Decimal inch | Millimeters | Family |
|---|---|---|---|
| 1/16 | 0.0625 | 1.588 | fractional |
| 5/64 | 0.0781 | 1.984 | fractional |
| 3/32 | 0.0938 | 2.381 | fractional |
| 7/64 | 0.1094 | 2.778 | fractional |
| 1/8 | 0.1250 | 3.175 | fractional |
| 9/64 | 0.1406 | 3.572 | fractional |
| 5/32 | 0.1563 | 3.969 | fractional |
| 11/64 | 0.1719 | 4.366 | fractional |
| 3/16 | 0.1875 | 4.763 | fractional |
| 13/64 | 0.2031 | 5.159 | fractional |
| 7/32 | 0.2188 | 5.556 | fractional |
| 15/64 | 0.2344 | 5.953 | fractional |
| 1/4 | 0.2500 | 6.350 | fractional |
| 17/64 | 0.2656 | 6.747 | fractional |
| 9/32 | 0.2813 | 7.144 | fractional |
| 19/64 | 0.2969 | 7.541 | fractional |
| 5/16 | 0.3125 | 7.938 | fractional |
| 21/64 | 0.3281 | 8.334 | fractional |
| 11/32 | 0.3438 | 8.731 | fractional |
| 23/64 | 0.3594 | 9.128 | fractional |
| 3/8 | 0.3750 | 9.525 | fractional |
| 25/64 | 0.3906 | 9.922 | fractional |
| 13/32 | 0.4063 | 10.319 | fractional |
| 27/64 | 0.4219 | 10.716 | fractional |
| 7/16 | 0.4375 | 11.113 | fractional |
| 29/64 | 0.4531 | 11.509 | fractional |
| 15/32 | 0.4688 | 11.906 | fractional |
| 31/64 | 0.4844 | 12.303 | fractional |
| 1/2 | 0.5000 | 12.700 | fractional |
| #43 | 0.0890 | 2.261 | number |
| #36 | 0.1065 | 2.705 | number |
| #29 | 0.1360 | 3.454 | number |
| #25 | 0.1495 | 3.797 | number |
| #21 | 0.1590 | 4.039 | number |
| #7 | 0.2010 | 5.105 | number |
| #3 | 0.2130 | 5.410 | number |
| F | 0.2570 | 6.528 | letter |
| I | 0.2720 | 6.909 | letter |
| Q | 0.3320 | 8.433 | letter |
What drill size chart should I use for fractional, number, letter, and metric bits?
Use the searchable table when you need to compare the name printed on a bit with its decimal inch and millimeter size. Fractional bits are common in general shop work, number and letter bits are common around tap drills, and metric bits are common with metric fasteners.
How do I find the closest drill bit size?
Start with the required decimal or millimeter value, then choose the nearest standard drill that fits the job. For tap drilling, use the thread chart or calculator before rounding because thread engagement changes the acceptable range.
Is a drill size chart the same as a tap drill chart?
No. A drill size chart lists drill diameters. A tap drill chart maps a thread callout to a starting hole size before tapping. If the hole will be threaded, open the tap drill chart or calculator instead of choosing only by diameter.
Printable drill bit size reference
For bench use, open the printable drill tap chart after confirming the live value. Old paper charts are convenient, but live tables are easier to correct when a value needs review.