Number (wire gauge) drill size chart #1–#97
Number drills get smaller as the number rises: #1 is 0.228 in, #80 is 0.0135 in and the micro sizes run to #97 (0.0059 in). Most machine-screw tap drills are number drills, like #7 for 1/4-20 and #29 for 8-32.
| Drill | Inch | mm | Nearest other drills | Tap drill for |
|---|---|---|---|---|
| #97 | 0.0059 | 0.150 | 1/64" (0.0156) · 0.15 mm (0.0059) | — |
| #96 | 0.0063 | 0.160 | 1/64" (0.0156) · 0.15 mm (0.0059) | — |
| #95 | 0.0067 | 0.170 | 1/64" (0.0156) · 0.15 mm (0.0059) | — |
| #94 | 0.0071 | 0.180 | 1/64" (0.0156) · 0.2 mm (0.0079) | — |
| #93 | 0.0075 | 0.190 | 1/64" (0.0156) · 0.2 mm (0.0079) | — |
| #92 | 0.0079 | 0.201 | 1/64" (0.0156) · 0.2 mm (0.0079) | — |
| #91 | 0.0083 | 0.211 | 1/64" (0.0156) · 0.2 mm (0.0079) | — |
| #90 | 0.0087 | 0.221 | 1/64" (0.0156) · 0.2 mm (0.0079) | — |
| #89 | 0.0091 | 0.231 | 1/64" (0.0156) · 0.25 mm (0.0098) | — |
| #88 | 0.0095 | 0.241 | 1/64" (0.0156) · 0.25 mm (0.0098) | — |
| #87 | 0.0100 | 0.254 | 1/64" (0.0156) · 0.25 mm (0.0098) | — |
| #86 | 0.0105 | 0.267 | 1/64" (0.0156) · 0.25 mm (0.0098) | — |
| #85 | 0.0110 | 0.279 | 1/64" (0.0156) · 0.3 mm (0.0118) | — |
| #84 | 0.0115 | 0.292 | 1/64" (0.0156) · 0.3 mm (0.0118) | — |
| #83 | 0.0120 | 0.305 | 1/64" (0.0156) · 0.3 mm (0.0118) | — |
| #82 | 0.0125 | 0.318 | 1/64" (0.0156) · 0.3 mm (0.0118) | — |
| #81 | 0.0130 | 0.330 | 1/64" (0.0156) · 0.35 mm (0.0138) | — |
| #80 | 0.0135 | 0.343 | 1/64" (0.0156) · 0.35 mm (0.0138) | — |
| #79 | 0.0145 | 0.368 | 1/64" (0.0156) · 0.35 mm (0.0138) | — |
| #78 | 0.0160 | 0.406 | 1/64" (0.0156) · 0.4 mm (0.0158) | — |
| #77 | 0.0180 | 0.457 | 1/64" (0.0156) · 0.45 mm (0.0177) | — |
| #76 | 0.0200 | 0.508 | 1/64" (0.0156) · 0.5 mm (0.0197) | — |
| #75 | 0.0210 | 0.533 | 1/64" (0.0156) · 0.55 mm (0.0216) | — |
| #74 | 0.0225 | 0.571 | 1/64" (0.0156) · 0.55 mm (0.0216) | — |
| #73 | 0.0240 | 0.610 | 1/32" (0.0313) · 0.6 mm (0.0236) | — |
| #72 | 0.0250 | 0.635 | 1/32" (0.0313) · 0.65 mm (0.0256) | — |
| #71 | 0.0260 | 0.660 | 1/32" (0.0313) · 0.65 mm (0.0256) | — |
| #70 | 0.0280 | 0.711 | 1/32" (0.0313) · 0.7 mm (0.0276) | — |
| #69 | 0.0292 | 0.742 | 1/32" (0.0313) · 0.75 mm (0.0295) | — |
| #68 | 0.0310 | 0.787 | 1/32" (0.0313) · 0.8 mm (0.0315) | — |
| #67 | 0.0320 | 0.813 | 1/32" (0.0313) · 0.8 mm (0.0315) | — |
| #66 | 0.0330 | 0.838 | 1/32" (0.0313) · 0.85 mm (0.0335) | — |
| #65 | 0.0350 | 0.889 | 1/32" (0.0313) · 0.9 mm (0.0354) | — |
| #64 | 0.0360 | 0.914 | 1/32" (0.0313) · 0.9 mm (0.0354) | — |
| #63 | 0.0370 | 0.940 | 1/32" (0.0313) · 0.95 mm (0.0374) | — |
| #62 | 0.0380 | 0.965 | 1/32" (0.0313) · 0.95 mm (0.0374) | — |
| #61 | 0.0390 | 0.991 | 1/32" (0.0313) · 1.0 mm (0.0394) | — |
| #60 | 0.0400 | 1.016 | 3/64" (0.0469) · 1.0 mm (0.0394) | — |
| #59 | 0.0410 | 1.041 | 3/64" (0.0469) · 1.05 mm (0.0413) | — |
| #58 | 0.0420 | 1.067 | 3/64" (0.0469) · 1.05 mm (0.0413) | — |
| #57 | 0.0430 | 1.092 | 3/64" (0.0469) · 1.1 mm (0.0433) | — |
| #56 | 0.0465 | 1.181 | 3/64" (0.0469) · 1.2 mm (0.0472) | — |
| #55 | 0.0520 | 1.321 | 3/64" (0.0469) · 1.3 mm (0.0512) | 0-80 (50%) |
| #54 | 0.0550 | 1.397 | 1/16" (0.0625) · 1.4 mm (0.0551) | 0-80 (form) |
| #53 | 0.0595 | 1.511 | 1/16" (0.0625) · 1.5 mm (0.0591) | 1-64, 1-72 |
| #52 | 0.0635 | 1.613 | 1/16" (0.0625) · 1.6 mm (0.0630) | 1-72 (50%) |
| #51 | 0.0670 | 1.702 | 1/16" (0.0625) · 1.7 mm (0.0669) | 1-64 (form), 1-72 (form) |
| #50 | 0.0700 | 1.778 | 1/16" (0.0625) · 1.8 mm (0.0709) | 2-56, 2-64 |
| #49 | 0.0730 | 1.854 | 5/64" (0.0781) · 1.85 mm (0.0728) | 2-56 (50%) |
| #48 | 0.0760 | 1.930 | 5/64" (0.0781) · 1.95 mm (0.0768) | 2-64 (50%) |
| #47 | 0.0785 | 1.994 | 5/64" (0.0781) · 2.0 mm (0.0787) | 3-48, 2-64 (form) |
| #46 | 0.0810 | 2.057 | 5/64" (0.0781) · 2.05 mm (0.0807) | — |
| #45 | 0.0820 | 2.083 | 5/64" (0.0781) · 2.1 mm (0.0827) | 3-56 |
| #44 | 0.0860 | 2.184 | 3/32" (0.0938) · 2.2 mm (0.0866) | 3-48 (50%), 3-56 (50%) |
| #43 | 0.0890 | 2.261 | 3/32" (0.0938) · 2.25 mm (0.0886) | 4-40, 3-48 (form), 3-56 (form) |
| #42 | 0.0935 | 2.375 | 3/32" (0.0938) · 2.35 mm (0.0925) | 4-48 |
| #41 | 0.0960 | 2.438 | 3/32" (0.0938) · 2.45 mm (0.0965) | 4-40 (50%) |
| #40 | 0.0980 | 2.489 | 3/32" (0.0938) · 2.5 mm (0.0984) | 4-48 (50%) |
| #39 | 0.0995 | 2.527 | 3/32" (0.0938) · 2.55 mm (0.1004) | — |
| #38 | 0.1015 | 2.578 | 3/32" (0.0938) · 2.6 mm (0.1024) | 5-40, 4-40 (form) |
| #37 | 0.1040 | 2.642 | 7/64" (0.1094) · 2.65 mm (0.1043) | 5-44, 4-48 (form) |
| #36 | 0.1065 | 2.705 | 7/64" (0.1094) · 2.7 mm (0.1063) | 6-32 |
| #35 | 0.1100 | 2.794 | 7/64" (0.1094) · 2.8 mm (0.1102) | 5-44 (50%) |
| #34 | 0.1110 | 2.819 | 7/64" (0.1094) · 2.8 mm (0.1102) | — |
| #33 | 0.1130 | 2.870 | 7/64" (0.1094) · 2.85 mm (0.1122) | 6-40, 5-40 (form) |
| #32 | 0.1160 | 2.946 | 7/64" (0.1094) · 2.95 mm (0.1161) | 5-44 (form), 6-32 (50%) |
| #31 | 0.1200 | 3.048 | 1/8" (0.1250) · 3.0 mm (0.1181) | 6-40 (50%) |
| #30 | 0.1285 | 3.264 | 1/8" (0.1250) · 3.3 mm (0.1299) | 6-40 (form) |
| #29 | 0.1360 | 3.454 | 9/64" (0.1406) · 3.5 mm (0.1378) | 8-32, 8-36 |
| #28 | 0.1405 | 3.569 | 9/64" (0.1406) · 3.6 mm (0.1417) | — |
| #27 | 0.1440 | 3.658 | 9/64" (0.1406) · 3.7 mm (0.1457) | 8-32 (50%) |
| #26 | 0.1470 | 3.734 | 9/64" (0.1406) · 3.7 mm (0.1457) | 8-36 (50%) |
| #25 | 0.1495 | 3.797 | 5/32" (0.1563) · 3.8 mm (0.1496) | 10-24, 8-32 (form) |
| #24 | 0.1520 | 3.861 | 5/32" (0.1563) · 3.9 mm (0.1535) | 8-36 (form) |
| #23 | 0.1540 | 3.912 | 5/32" (0.1563) · 3.9 mm (0.1535) | — |
| #22 | 0.1570 | 3.988 | 5/32" (0.1563) · 4.0 mm (0.1575) | — |
| #21 | 0.1590 | 4.039 | 5/32" (0.1563) · 4.0 mm (0.1575) | 10-32 |
| #20 | 0.1610 | 4.089 | 5/32" (0.1563) · 4.1 mm (0.1614) | 10-24 (50%) |
| #19 | 0.1660 | 4.216 | 11/64" (0.1719) · 4.2 mm (0.1653) | — |
| #18 | 0.1695 | 4.305 | 11/64" (0.1719) · 4.3 mm (0.1693) | 10-32 (50%) |
| #17 | 0.1730 | 4.394 | 11/64" (0.1719) · 4.4 mm (0.1732) | — |
| #16 | 0.1770 | 4.496 | 11/64" (0.1719) · 4.5 mm (0.1772) | 12-24, 10-32 (form) |
| #15 | 0.1800 | 4.572 | 3/16" (0.1875) · 4.6 mm (0.1811) | — |
| #14 | 0.1820 | 4.623 | 3/16" (0.1875) · 4.6 mm (0.1811) | 12-28 |
| #13 | 0.1850 | 4.699 | 3/16" (0.1875) · 4.7 mm (0.1850) | 12-32 |
| #12 | 0.1890 | 4.801 | 3/16" (0.1875) · 4.8 mm (0.1890) | 12-24 (50%) |
| #11 | 0.1910 | 4.851 | 3/16" (0.1875) · 4.9 mm (0.1929) | — |
| #10 | 0.1935 | 4.915 | 3/16" (0.1875) · 4.9 mm (0.1929) | 12-28 (50%) |
| #9 | 0.1960 | 4.978 | 13/64" (0.2031) · 5.0 mm (0.1968) | 12-32 (50%) |
| #8 | 0.1990 | 5.055 | 13/64" (0.2031) · 5.1 mm (0.2008) | 12-24 (form) |
| #7 | 0.2010 | 5.105 | 13/64" (0.2031) · 5.1 mm (0.2008) | 1/4-20, 12-28 (form) |
| #6 | 0.2040 | 5.182 | 13/64" (0.2031) · 5.2 mm (0.2047) | — |
| #5 | 0.2055 | 5.220 | 13/64" (0.2031) · 5.2 mm (0.2047) | — |
| #4 | 0.2090 | 5.309 | 13/64" (0.2031) · 5.3 mm (0.2087) | — |
| #3 | 0.2130 | 5.410 | 7/32" (0.2188) · 5.4 mm (0.2126) | 1/4-28 |
| #2 | 0.2210 | 5.613 | 7/32" (0.2188) · 5.6 mm (0.2205) | — |
| #1 | 0.2280 | 5.791 | 15/64" (0.2344) · 5.8 mm (0.2283) | 1/4-20 (form), 1/4-28 (50%), 1/4-32 (50%) |
Common questions
- What size is a #7 drill?
- 0.201 in (5.105 mm), the 1/4-20 tap drill.
- What drill is used for 10-32?
- A #21 drill (0.159 in) at about 75% thread.
- Why do number drills get smaller as the number goes up?
- They follow the old Stubs steel wire gauge, where a higher gauge number is a thinner wire.
Calculators that use this data
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