Drill Size Chart
Complete reference of number drills (#1 through #80), letter drills (A through Z), and fractional drills (1/64" through 1"). All values from Machinery's Handbook. Searchable and sortable by diameter in inches or millimeters.
Last updated April 2026
170 drills
| Drill Size↕ | Type | Diameter (in)↑ | Diameter (mm) |
|---|---|---|---|
| #80 | number | 0.0135" | 0.343 mm |
| #79 | number | 0.0145" | 0.368 mm |
| 1/64" | fractional | 0.0156" | 0.397 mm |
| #78 | number | 0.0160" | 0.406 mm |
| #77 | number | 0.0180" | 0.457 mm |
| #76 | number | 0.0200" | 0.508 mm |
| #75 | number | 0.0210" | 0.533 mm |
| #74 | number | 0.0225" | 0.571 mm |
| #73 | number | 0.0240" | 0.610 mm |
| #72 | number | 0.0250" | 0.635 mm |
| #71 | number | 0.0260" | 0.660 mm |
| #70 | number | 0.0280" | 0.711 mm |
| #69 | number | 0.0292" | 0.742 mm |
| #68 | number | 0.0310" | 0.787 mm |
| 1/32" | fractional | 0.0313" | 0.794 mm |
| #67 | number | 0.0320" | 0.813 mm |
| #66 | number | 0.0330" | 0.838 mm |
| #65 | number | 0.0350" | 0.889 mm |
| #64 | number | 0.0360" | 0.914 mm |
| #63 | number | 0.0370" | 0.940 mm |
| #62 | number | 0.0380" | 0.965 mm |
| #61 | number | 0.0390" | 0.991 mm |
| #60 | number | 0.0400" | 1.016 mm |
| #59 | number | 0.0410" | 1.041 mm |
| #58 | number | 0.0420" | 1.067 mm |
| #57 | number | 0.0430" | 1.092 mm |
| #56 | number | 0.0465" | 1.181 mm |
| 3/64" | fractional | 0.0469" | 1.191 mm |
| #55 | number | 0.0520" | 1.321 mm |
| #54 | number | 0.0550" | 1.397 mm |
| #53 | number | 0.0595" | 1.511 mm |
| 1/16" | fractional | 0.0625" | 1.587 mm |
| #52 | number | 0.0635" | 1.613 mm |
| #51 | number | 0.0670" | 1.702 mm |
| #50 | number | 0.0700" | 1.778 mm |
| #49 | number | 0.0730" | 1.854 mm |
| #48 | number | 0.0760" | 1.930 mm |
| 5/64" | fractional | 0.0781" | 1.984 mm |
| #47 | number | 0.0785" | 1.994 mm |
| #46 | number | 0.0810" | 2.057 mm |
| #45 | number | 0.0820" | 2.083 mm |
| #44 | number | 0.0860" | 2.184 mm |
| #43 | number | 0.0890" | 2.261 mm |
| #42 | number | 0.0935" | 2.375 mm |
| 3/32" | fractional | 0.0938" | 2.381 mm |
| #41 | number | 0.0960" | 2.438 mm |
| #40 | number | 0.0980" | 2.489 mm |
| #39 | number | 0.0995" | 2.527 mm |
| #38 | number | 0.1015" | 2.578 mm |
| #37 | number | 0.1040" | 2.642 mm |
| #36 | number | 0.1065" | 2.705 mm |
| 7/64" | fractional | 0.1094" | 2.778 mm |
| #35 | number | 0.1100" | 2.794 mm |
| #34 | number | 0.1110" | 2.819 mm |
| #33 | number | 0.1130" | 2.870 mm |
| #32 | number | 0.1160" | 2.946 mm |
| #31 | number | 0.1200" | 3.048 mm |
| 1/8" | fractional | 0.1250" | 3.175 mm |
| #30 | number | 0.1285" | 3.264 mm |
| #29 | number | 0.1360" | 3.454 mm |
| #28 | number | 0.1405" | 3.569 mm |
| 9/64" | fractional | 0.1406" | 3.572 mm |
| #27 | number | 0.1440" | 3.658 mm |
| #26 | number | 0.1470" | 3.734 mm |
| #25 | number | 0.1495" | 3.797 mm |
| #24 | number | 0.1520" | 3.861 mm |
| #23 | number | 0.1540" | 3.912 mm |
| 5/32" | fractional | 0.1563" | 3.969 mm |
| #22 | number | 0.1570" | 3.988 mm |
| #21 | number | 0.1590" | 4.039 mm |
| #20 | number | 0.1610" | 4.089 mm |
| #19 | number | 0.1660" | 4.216 mm |
| #18 | number | 0.1695" | 4.305 mm |
| 11/64" | fractional | 0.1719" | 4.366 mm |
| #17 | number | 0.1730" | 4.394 mm |
| #16 | number | 0.1770" | 4.496 mm |
| #15 | number | 0.1800" | 4.572 mm |
| #14 | number | 0.1820" | 4.623 mm |
| #13 | number | 0.1850" | 4.699 mm |
| 3/16" | fractional | 0.1875" | 4.762 mm |
| #12 | number | 0.1890" | 4.801 mm |
| #11 | number | 0.1910" | 4.851 mm |
| #10 | number | 0.1935" | 4.915 mm |
| #9 | number | 0.1960" | 4.978 mm |
| #8 | number | 0.1990" | 5.055 mm |
| #7 | number | 0.2010" | 5.105 mm |
| 13/64" | fractional | 0.2031" | 5.159 mm |
| #6 | number | 0.2040" | 5.182 mm |
| #5 | number | 0.2055" | 5.220 mm |
| #4 | number | 0.2090" | 5.309 mm |
| #3 | number | 0.2130" | 5.410 mm |
| 7/32" | fractional | 0.2188" | 5.556 mm |
| #2 | number | 0.2210" | 5.613 mm |
| #1 | number | 0.2280" | 5.791 mm |
| A | letter | 0.2340" | 5.944 mm |
| 15/64" | fractional | 0.2344" | 5.953 mm |
| B | letter | 0.2380" | 6.045 mm |
| C | letter | 0.2420" | 6.147 mm |
| D | letter | 0.2460" | 6.248 mm |
| E | letter | 0.2500" | 6.350 mm |
| 1/4" | fractional | 0.2500" | 6.350 mm |
| F | letter | 0.2570" | 6.528 mm |
| G | letter | 0.2610" | 6.629 mm |
| 17/64" | fractional | 0.2656" | 6.747 mm |
| H | letter | 0.2660" | 6.756 mm |
| I | letter | 0.2720" | 6.909 mm |
| J | letter | 0.2770" | 7.036 mm |
| K | letter | 0.2810" | 7.137 mm |
| 9/32" | fractional | 0.2813" | 7.144 mm |
| L | letter | 0.2900" | 7.366 mm |
| M | letter | 0.2950" | 7.493 mm |
| 19/64" | fractional | 0.2969" | 7.541 mm |
| N | letter | 0.3020" | 7.671 mm |
| 5/16" | fractional | 0.3125" | 7.938 mm |
| O | letter | 0.3160" | 8.026 mm |
| P | letter | 0.3230" | 8.204 mm |
| 21/64" | fractional | 0.3281" | 8.334 mm |
| Q | letter | 0.3320" | 8.433 mm |
| R | letter | 0.3390" | 8.611 mm |
| 11/32" | fractional | 0.3438" | 8.731 mm |
| S | letter | 0.3480" | 8.839 mm |
| T | letter | 0.3580" | 9.093 mm |
| 23/64" | fractional | 0.3594" | 9.128 mm |
| U | letter | 0.3680" | 9.347 mm |
| 3/8" | fractional | 0.3750" | 9.525 mm |
| V | letter | 0.3770" | 9.576 mm |
| W | letter | 0.3860" | 9.804 mm |
| 25/64" | fractional | 0.3906" | 9.922 mm |
| X | letter | 0.3970" | 10.084 mm |
| Y | letter | 0.4040" | 10.262 mm |
| 13/32" | fractional | 0.4063" | 10.319 mm |
| Z | letter | 0.4130" | 10.490 mm |
| 27/64" | fractional | 0.4219" | 10.716 mm |
| 7/16" | fractional | 0.4375" | 11.112 mm |
| 29/64" | fractional | 0.4531" | 11.509 mm |
| 15/32" | fractional | 0.4688" | 11.906 mm |
| 31/64" | fractional | 0.4844" | 12.303 mm |
| 1/2" | fractional | 0.5000" | 12.700 mm |
| 33/64" | fractional | 0.5156" | 13.097 mm |
| 17/32" | fractional | 0.5313" | 13.494 mm |
| 35/64" | fractional | 0.5469" | 13.891 mm |
| 9/16" | fractional | 0.5625" | 14.287 mm |
| 37/64" | fractional | 0.5781" | 14.684 mm |
| 19/32" | fractional | 0.5938" | 15.081 mm |
| 39/64" | fractional | 0.6094" | 15.478 mm |
| 5/8" | fractional | 0.6250" | 15.875 mm |
| 41/64" | fractional | 0.6406" | 16.272 mm |
| 21/32" | fractional | 0.6563" | 16.669 mm |
| 43/64" | fractional | 0.6719" | 17.066 mm |
| 11/16" | fractional | 0.6875" | 17.462 mm |
| 45/64" | fractional | 0.7031" | 17.859 mm |
| 23/32" | fractional | 0.7188" | 18.256 mm |
| 47/64" | fractional | 0.7344" | 18.653 mm |
| 3/4" | fractional | 0.7500" | 19.050 mm |
| 49/64" | fractional | 0.7656" | 19.447 mm |
| 25/32" | fractional | 0.7813" | 19.844 mm |
| 51/64" | fractional | 0.7969" | 20.241 mm |
| 13/16" | fractional | 0.8125" | 20.637 mm |
| 53/64" | fractional | 0.8281" | 21.034 mm |
| 27/32" | fractional | 0.8438" | 21.431 mm |
| 55/64" | fractional | 0.8594" | 21.828 mm |
| 7/8" | fractional | 0.8750" | 22.225 mm |
| 57/64" | fractional | 0.8906" | 22.622 mm |
| 29/32" | fractional | 0.9063" | 23.019 mm |
| 59/64" | fractional | 0.9219" | 23.416 mm |
| 15/16" | fractional | 0.9375" | 23.813 mm |
| 61/64" | fractional | 0.9531" | 24.209 mm |
| 31/32" | fractional | 0.9688" | 24.606 mm |
| 63/64" | fractional | 0.9844" | 25.003 mm |
| 1" | fractional | 1.0000" | 25.400 mm |
Drill sizes per Machinery's Handbook, 30th Edition. Number drills #1-#80, letter drills A-Z, fractional drills 1/64" through 1" in 1/64" increments.
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Frequently Asked Questions
What size is a #7 drill?
A #7 drill is 0.2010 inches (5.105 mm) in diameter. It is the standard 75% thread engagement tap drill for 1/4-20 UNC threads.
What size is a letter F drill?
A letter F drill is 0.2570 inches (6.528 mm) in diameter. It is the standard tap drill for 5/16-18 UNC threads.