# Drill size chart

Number drills run from #80 (0.0135 in, 0.34 mm) up to #1 (0.2280 in, 5.79 mm), letter drills continue from A (0.2340 in) to Z (0.4130 in), and fractional drills step by 1/64 in up to 1 in. For example, a #7 drill is 0.2010 in (5.11 mm), the tap drill for 1/4-20.

Data: https://machinistcharts.com/data/drill-sizes.csv

## All inch drills by size

| Drill | Series | Inch | mm | Nearest metric mm | Tap drill for |
|---|---|---|---|---|---|
| #80 | number | 0.0135 | 0.34 | 0.35 |  |
| #79 | number | 0.0145 | 0.37 | 0.35 |  |
| 1/64 | fractional | 0.0156 | 0.40 | 0.4 |  |
| #78 | number | 0.0160 | 0.41 | 0.4 |  |
| #77 | number | 0.0180 | 0.46 | 0.45 |  |
| #76 | number | 0.0200 | 0.51 | 0.5 |  |
| #75 | number | 0.0210 | 0.53 | 0.55 |  |
| #74 | number | 0.0225 | 0.57 | 0.55 |  |
| #73 | number | 0.0240 | 0.61 | 0.6 |  |
| #72 | number | 0.0250 | 0.64 | 0.65 |  |
| #71 | number | 0.0260 | 0.66 | 0.65 |  |
| #70 | number | 0.0280 | 0.71 | 0.7 |  |
| #69 | number | 0.0292 | 0.74 | 0.75 |  |
| #68 | number | 0.0310 | 0.79 | 0.8 |  |
| 1/32 | fractional | 0.0312 | 0.79 | 0.8 |  |
| #67 | number | 0.0320 | 0.81 | 0.8 |  |
| #66 | number | 0.0330 | 0.84 | 0.85 |  |
| #65 | number | 0.0350 | 0.89 | 0.9 |  |
| #64 | number | 0.0360 | 0.91 | 0.9 |  |
| #63 | number | 0.0370 | 0.94 | 0.95 |  |
| #62 | number | 0.0380 | 0.97 | 0.95 |  |
| #61 | number | 0.0390 | 0.99 | 1.0 |  |
| #60 | number | 0.0400 | 1.02 | 1.0 |  |
| #59 | number | 0.0410 | 1.04 | 1.05 |  |
| #58 | number | 0.0420 | 1.07 | 1.05 |  |
| #57 | number | 0.0430 | 1.09 | 1.1 |  |
| #56 | number | 0.0465 | 1.18 | 1.2 |  |
| 3/64 | fractional | 0.0469 | 1.19 | 1.2 | #0-80 UNF |
| #55 | number | 0.0520 | 1.32 | 1.3 |  |
| #54 | number | 0.0550 | 1.40 | 1.4 |  |
| #53 | number | 0.0595 | 1.51 | 1.5 | #1-64 UNC; #1-72 UNF |
| 1/16 | fractional | 0.0625 | 1.59 | 1.6 |  |
| #52 | number | 0.0635 | 1.61 | 1.6 |  |
| #51 | number | 0.0670 | 1.70 | 1.7 |  |
| #50 | number | 0.0700 | 1.78 | 1.8 | #2-56 UNC; #2-64 UNF |
| #49 | number | 0.0730 | 1.85 | 1.85 |  |
| #48 | number | 0.0760 | 1.93 | 1.95 |  |
| 5/64 | fractional | 0.0781 | 1.98 | 2.0 |  |
| #47 | number | 0.0785 | 1.99 | 2.0 | #3-48 UNC |
| #46 | number | 0.0810 | 2.06 | 2.05 |  |
| #45 | number | 0.0820 | 2.08 | 2.1 | #3-56 UNF |
| #44 | number | 0.0860 | 2.18 | 2.2 |  |
| #43 | number | 0.0890 | 2.26 | 2.25 | #4-40 UNC |
| #42 | number | 0.0935 | 2.37 | 2.35 | #4-48 UNF |
| 3/32 | fractional | 0.0938 | 2.38 | 2.4 |  |
| #41 | number | 0.0960 | 2.44 | 2.45 |  |
| #40 | number | 0.0980 | 2.49 | 2.5 |  |
| #39 | number | 0.0995 | 2.53 | 2.55 |  |
| #38 | number | 0.1015 | 2.58 | 2.6 | #5-40 UNC |
| #37 | number | 0.1040 | 2.64 | 2.65 | #5-44 UNF |
| #36 | number | 0.1065 | 2.71 | 2.7 | #6-32 UNC |
| 7/64 | fractional | 0.1094 | 2.78 | 2.8 |  |
| #35 | number | 0.1100 | 2.79 | 2.8 |  |
| #34 | number | 0.1110 | 2.82 | 2.8 |  |
| #33 | number | 0.1130 | 2.87 | 2.85 | #6-40 UNF |
| #32 | number | 0.1160 | 2.95 | 2.95 |  |
| #31 | number | 0.1200 | 3.05 | 3.0 |  |
| 1/8 | fractional | 0.1250 | 3.17 | 3.2 |  |
| #30 | number | 0.1285 | 3.26 | 3.3 |  |
| #29 | number | 0.1360 | 3.45 | 3.5 | #8-32 UNC; #8-36 UNF |
| #28 | number | 0.1405 | 3.57 | 3.6 |  |
| 9/64 | fractional | 0.1406 | 3.57 | 3.6 |  |
| #27 | number | 0.1440 | 3.66 | 3.7 |  |
| #26 | number | 0.1470 | 3.73 | 3.7 |  |
| #25 | number | 0.1495 | 3.80 | 3.8 | #10-24 UNC |
| #24 | number | 0.1520 | 3.86 | 3.9 |  |
| #23 | number | 0.1540 | 3.91 | 3.9 |  |
| 5/32 | fractional | 0.1562 | 3.97 | 4.0 |  |
| #22 | number | 0.1570 | 3.99 | 4.0 |  |
| #21 | number | 0.1590 | 4.04 | 4.0 | #10-32 UNF |
| #20 | number | 0.1610 | 4.09 | 4.1 |  |
| #19 | number | 0.1660 | 4.22 | 4.2 |  |
| #18 | number | 0.1695 | 4.31 | 4.3 |  |
| 11/64 | fractional | 0.1719 | 4.37 | 4.4 |  |
| #17 | number | 0.1730 | 4.39 | 4.4 |  |
| #16 | number | 0.1770 | 4.50 | 4.5 | #12-24 UNC |
| #15 | number | 0.1800 | 4.57 | 4.6 |  |
| #14 | number | 0.1820 | 4.62 | 4.6 | #12-28 UNF |
| #13 | number | 0.1850 | 4.70 | 4.7 |  |
| 3/16 | fractional | 0.1875 | 4.76 | 4.8 |  |
| #12 | number | 0.1890 | 4.80 | 4.8 |  |
| #11 | number | 0.1910 | 4.85 | 4.9 |  |
| #10 | number | 0.1935 | 4.91 | 4.9 |  |
| #9 | number | 0.1960 | 4.98 | 5.0 |  |
| #8 | number | 0.1990 | 5.05 | 5.1 |  |
| #7 | number | 0.2010 | 5.11 | 5.1 | 1/4-20 UNC |
| 13/64 | fractional | 0.2031 | 5.16 | 5.2 |  |
| #6 | number | 0.2040 | 5.18 | 5.2 |  |
| #5 | number | 0.2055 | 5.22 | 5.2 |  |
| #4 | number | 0.2090 | 5.31 | 5.3 |  |
| #3 | number | 0.2130 | 5.41 | 5.4 | 1/4-28 UNF |
| 7/32 | fractional | 0.2188 | 5.56 | 5.6 |  |
| #2 | number | 0.2210 | 5.61 | 5.6 |  |
| #1 | number | 0.2280 | 5.79 | 5.8 |  |
| A | letter | 0.2340 | 5.94 | 5.9 |  |
| 15/64 | fractional | 0.2344 | 5.95 | 6.0 |  |
| B | letter | 0.2380 | 6.05 | 6.0 |  |
| C | letter | 0.2420 | 6.15 | 6.1 |  |
| D | letter | 0.2460 | 6.25 | 6.2 |  |
| 1/4 | fractional | 0.2500 | 6.35 | 6.3 |  |
| E | letter | 0.2500 | 6.35 | 6.3 |  |
| F | letter | 0.2570 | 6.53 | 6.5 | 5/16-18 UNC |
| G | letter | 0.2610 | 6.63 | 6.6 |  |
| 17/64 | fractional | 0.2656 | 6.75 | 6.7 |  |
| H | letter | 0.2660 | 6.76 | 6.8 |  |
| I | letter | 0.2720 | 6.91 | 6.9 | 5/16-24 UNF |
| J | letter | 0.2770 | 7.04 | 7.0 |  |
| K | letter | 0.2810 | 7.14 | 7.1 |  |
| 9/32 | fractional | 0.2812 | 7.14 | 7.1 |  |
| L | letter | 0.2900 | 7.37 | 7.4 |  |
| M | letter | 0.2950 | 7.49 | 7.5 |  |
| 19/64 | fractional | 0.2969 | 7.54 | 7.5 |  |
| N | letter | 0.3020 | 7.67 | 7.7 |  |
| 5/16 | fractional | 0.3125 | 7.94 | 7.9 | 3/8-16 UNC |
| O | letter | 0.3160 | 8.03 | 8.0 |  |
| P | letter | 0.3230 | 8.20 | 8.2 |  |
| 21/64 | fractional | 0.3281 | 8.33 | 8.3 |  |
| Q | letter | 0.3320 | 8.43 | 8.4 | 3/8-24 UNF |
| R | letter | 0.3390 | 8.61 | 8.6 |  |
| 11/32 | fractional | 0.3438 | 8.73 | 8.7 |  |
| S | letter | 0.3480 | 8.84 | 8.8 |  |
| T | letter | 0.3580 | 9.09 | 9.1 |  |
| 23/64 | fractional | 0.3594 | 9.13 | 9.1 |  |
| U | letter | 0.3680 | 9.35 | 9.3 | 7/16-14 UNC |
| 3/8 | fractional | 0.3750 | 9.52 | 9.5 |  |
| V | letter | 0.3770 | 9.58 | 9.6 |  |
| W | letter | 0.3860 | 9.80 | 9.8 |  |
| 25/64 | fractional | 0.3906 | 9.92 | 9.9 | 7/16-20 UNF |
| X | letter | 0.3970 | 10.08 | 10.1 |  |
| Y | letter | 0.4040 | 10.26 | 10.3 |  |
| 13/32 | fractional | 0.4062 | 10.32 | 10.3 |  |
| Z | letter | 0.4130 | 10.49 | 10.5 |  |
| 27/64 | fractional | 0.4219 | 10.72 | 10.7 | 1/2-13 UNC |
| 7/16 | fractional | 0.4375 | 11.11 | 11.1 |  |
| 29/64 | fractional | 0.4531 | 11.51 | 11.5 | 1/2-20 UNF |
| 15/32 | fractional | 0.4688 | 11.91 | 11.9 |  |
| 31/64 | fractional | 0.4844 | 12.30 | 12.3 | 9/16-12 UNC |
| 1/2 | fractional | 0.5000 | 12.70 | 12.7 |  |
| 33/64 | fractional | 0.5156 | 13.10 | 13.1 | 9/16-18 UNF |
| 17/32 | fractional | 0.5312 | 13.49 | 13.5 | 5/8-11 UNC |
| 35/64 | fractional | 0.5469 | 13.89 | 13.9 |  |
| 9/16 | fractional | 0.5625 | 14.29 | 14.3 |  |
| 37/64 | fractional | 0.5781 | 14.68 | 14.7 | 5/8-18 UNF |
| 19/32 | fractional | 0.5938 | 15.08 | 15.1 |  |
| 39/64 | fractional | 0.6094 | 15.48 | 15.5 |  |
| 5/8 | fractional | 0.6250 | 15.88 | 15.9 |  |
| 41/64 | fractional | 0.6406 | 16.27 | 16.3 |  |
| 21/32 | fractional | 0.6562 | 16.67 | 16.7 | 3/4-10 UNC |
| 43/64 | fractional | 0.6719 | 17.07 | 17.1 |  |
| 11/16 | fractional | 0.6875 | 17.46 | 17.5 | 3/4-16 UNF |
| 45/64 | fractional | 0.7031 | 17.86 | 17.9 |  |
| 23/32 | fractional | 0.7188 | 18.26 | 18.3 |  |
| 47/64 | fractional | 0.7344 | 18.65 | 18.7 |  |
| 3/4 | fractional | 0.7500 | 19.05 | 19.0 |  |
| 49/64 | fractional | 0.7656 | 19.45 | 19.4 | 7/8-9 UNC |
| 25/32 | fractional | 0.7812 | 19.84 | 19.8 |  |
| 51/64 | fractional | 0.7969 | 20.24 | 20.2 |  |
| 13/16 | fractional | 0.8125 | 20.64 | 20.6 | 7/8-14 UNF |
| 53/64 | fractional | 0.8281 | 21.03 | 21.0 |  |
| 27/32 | fractional | 0.8438 | 21.43 | 21.4 |  |
| 55/64 | fractional | 0.8594 | 21.83 | 21.8 |  |
| 7/8 | fractional | 0.8750 | 22.22 | 22.2 | 1-8 UNC |
| 57/64 | fractional | 0.8906 | 22.62 | 22.6 |  |
| 29/32 | fractional | 0.9062 | 23.02 | 23.0 |  |
| 59/64 | fractional | 0.9219 | 23.42 | 23.4 | 1-12 UNF |
| 15/16 | fractional | 0.9375 | 23.81 | 23.8 |  |
| 61/64 | fractional | 0.9531 | 24.21 | 24.2 |  |
| 31/32 | fractional | 0.9688 | 24.61 | 24.6 |  |
| 63/64 | fractional | 0.9844 | 25.00 | 25.0 |  |
| 1 | fractional | 1.0000 | 25.40 | 25.4 |  |

## Metric drill to nearest inch drill

| Metric mm | Inch | Nearest inch drill | Its size in |
|---|---|---|---|
| 0.5 | 0.0197 | #76 | 0.0200 |
| 1.0 | 0.0394 | #61 | 0.0390 |
| 1.5 | 0.0591 | #53 | 0.0595 |
| 2.0 | 0.0787 | #47 | 0.0785 |
| 2.5 | 0.0984 | #40 | 0.0980 |
| 3.0 | 0.1181 | #31 | 0.1200 |
| 3.5 | 0.1378 | #29 | 0.1360 |
| 4.0 | 0.1575 | #22 | 0.1570 |
| 4.5 | 0.1772 | #16 | 0.1770 |
| 5.0 | 0.1969 | #9 | 0.1960 |
| 5.5 | 0.2165 | 7/32" | 0.2188 |
| 6.0 | 0.2362 | Letter B | 0.2380 |
| 6.5 | 0.2559 | Letter F | 0.2570 |
| 7.0 | 0.2756 | Letter J | 0.2770 |
| 7.5 | 0.2953 | Letter M | 0.2950 |
| 8.0 | 0.3150 | Letter O | 0.3160 |
| 8.5 | 0.3346 | Letter Q | 0.3320 |
| 9.0 | 0.3543 | Letter T | 0.3580 |
| 9.5 | 0.3740 | 3/8" | 0.3750 |
| 10.0 | 0.3937 | 25/64" | 0.3906 |
| 10.5 | 0.4134 | Letter Z | 0.4130 |
| 11.0 | 0.4331 | 7/16" | 0.4375 |
| 11.5 | 0.4528 | 29/64" | 0.4531 |
| 12.0 | 0.4724 | 15/32" | 0.4688 |
| 12.5 | 0.4921 | 31/64" | 0.4844 |
| 13.0 | 0.5118 | 33/64" | 0.5156 |

Source page: https://machinistcharts.com/drill-size/
Updated: 2026-10-06
Publisher: MachinistCharts (https://machinistcharts.com)