Drill Size Chart —
Number, Letter, and Fractional Decimal Equivalents
Combined Drill Size Chart
All four series in one list, sorted smallest to largest: number drills #80 to #1, letter drills A to Z, fractional drills 1/64" to 1", and standard metric drills from 1.0 to 13.0 mm including the common metric tap drill sizes (3.3, 4.2, 6.8, 8.5, 10.2 mm). Read down the left half first, then the right. Two sizes per row.[1]
| Drill | Decimal (in) | mm | Drill | Decimal (in) | mm |
|---|---|---|---|---|---|
| #80 | 0.0135 | 0.34 | #10 | 0.1935 | 4.91 |
| #79 | 0.0145 | 0.37 | #9 | 0.1960 | 4.98 |
| 1/64" | 0.0156 | 0.40 | 5 mm | 0.1969 | 5.00 |
| #78 | 0.0160 | 0.41 | #8 | 0.1990 | 5.05 |
| #77 | 0.0180 | 0.46 | #7 | 0.2010 | 5.11 |
| #76 | 0.0200 | 0.51 | 13/64" | 0.2031 | 5.16 |
| #75 | 0.0210 | 0.53 | #6 | 0.2040 | 5.18 |
| #74 | 0.0225 | 0.57 | #5 | 0.2055 | 5.22 |
| #73 | 0.0240 | 0.61 | #4 | 0.2090 | 5.31 |
| #72 | 0.0250 | 0.64 | #3 | 0.2130 | 5.41 |
| #71 | 0.0260 | 0.66 | 5.5 mm | 0.2165 | 5.50 |
| #70 | 0.0280 | 0.71 | 7/32" | 0.2188 | 5.56 |
| #69 | 0.0292 | 0.74 | #2 | 0.2210 | 5.61 |
| #68 | 0.0310 | 0.79 | #1 | 0.2280 | 5.79 |
| 1/32" | 0.0312 | 0.79 | A | 0.2340 | 5.94 |
| #67 | 0.0320 | 0.81 | 15/64" | 0.2344 | 5.95 |
| #66 | 0.0330 | 0.84 | 6 mm | 0.2362 | 6.00 |
| #65 | 0.0350 | 0.89 | B | 0.2380 | 6.05 |
| #64 | 0.0360 | 0.91 | C | 0.2420 | 6.15 |
| #63 | 0.0370 | 0.94 | D | 0.2460 | 6.25 |
| #62 | 0.0380 | 0.97 | E | 0.2500 | 6.35 |
| #61 | 0.0390 | 0.99 | 1/4" | 0.2500 | 6.35 |
| 1 mm | 0.0394 | 1.00 | 6.5 mm | 0.2559 | 6.50 |
| #60 | 0.0400 | 1.02 | F | 0.2570 | 6.53 |
| #59 | 0.0410 | 1.04 | G | 0.2610 | 6.63 |
| #58 | 0.0420 | 1.07 | 17/64" | 0.2656 | 6.75 |
| #57 | 0.0430 | 1.09 | H | 0.2660 | 6.76 |
| #56 | 0.0465 | 1.18 | 6.8 mm | 0.2677 | 6.80 |
| 3/64" | 0.0469 | 1.19 | I | 0.2720 | 6.91 |
| #55 | 0.0520 | 1.32 | 7 mm | 0.2756 | 7.00 |
| #54 | 0.0550 | 1.40 | J | 0.2770 | 7.04 |
| 1.5 mm | 0.0591 | 1.50 | K | 0.2810 | 7.14 |
| #53 | 0.0595 | 1.51 | 9/32" | 0.2812 | 7.14 |
| 1/16" | 0.0625 | 1.59 | L | 0.2900 | 7.37 |
| #52 | 0.0635 | 1.61 | M | 0.2950 | 7.49 |
| #51 | 0.0670 | 1.70 | 7.5 mm | 0.2953 | 7.50 |
| #50 | 0.0700 | 1.78 | 19/64" | 0.2969 | 7.54 |
| #49 | 0.0730 | 1.85 | N | 0.3020 | 7.67 |
| #48 | 0.0760 | 1.93 | 5/16" | 0.3125 | 7.94 |
| 5/64" | 0.0781 | 1.98 | 8 mm | 0.3150 | 8.00 |
| #47 | 0.0785 | 1.99 | O | 0.3160 | 8.03 |
| 2 mm | 0.0787 | 2.00 | P | 0.3230 | 8.20 |
| #46 | 0.0810 | 2.06 | 21/64" | 0.3281 | 8.33 |
| #45 | 0.0820 | 2.08 | Q | 0.3320 | 8.43 |
| #44 | 0.0860 | 2.18 | 8.5 mm | 0.3346 | 8.50 |
| #43 | 0.0890 | 2.26 | 8.5 mm | 0.3346 | 8.50 |
| #42 | 0.0935 | 2.37 | R | 0.3390 | 8.61 |
| 3/32" | 0.0938 | 2.38 | 11/32" | 0.3438 | 8.73 |
| #41 | 0.0960 | 2.44 | S | 0.3480 | 8.84 |
| #40 | 0.0980 | 2.49 | 9 mm | 0.3543 | 9.00 |
| 2.5 mm | 0.0984 | 2.50 | T | 0.3580 | 9.09 |
| #39 | 0.0995 | 2.53 | 23/64" | 0.3594 | 9.13 |
| #38 | 0.1015 | 2.58 | U | 0.3680 | 9.35 |
| #37 | 0.1040 | 2.64 | 9.5 mm | 0.3740 | 9.50 |
| #36 | 0.1065 | 2.71 | 3/8" | 0.3750 | 9.52 |
| 7/64" | 0.1094 | 2.78 | V | 0.3770 | 9.58 |
| #35 | 0.1100 | 2.79 | W | 0.3860 | 9.80 |
| #34 | 0.1110 | 2.82 | 25/64" | 0.3906 | 9.92 |
| #33 | 0.1130 | 2.87 | 10 mm | 0.3937 | 10.00 |
| #32 | 0.1160 | 2.95 | X | 0.3970 | 10.08 |
| 3 mm | 0.1181 | 3.00 | 10.2 mm | 0.4016 | 10.20 |
| #31 | 0.1200 | 3.05 | Y | 0.4040 | 10.26 |
| 1/8" | 0.1250 | 3.17 | 13/32" | 0.4062 | 10.32 |
| #30 | 0.1285 | 3.26 | Z | 0.4130 | 10.49 |
| 3.3 mm | 0.1299 | 3.30 | 10.5 mm | 0.4134 | 10.50 |
| #29 | 0.1360 | 3.45 | 27/64" | 0.4219 | 10.72 |
| 3.5 mm | 0.1378 | 3.50 | 11 mm | 0.4331 | 11.00 |
| #28 | 0.1405 | 3.57 | 7/16" | 0.4375 | 11.11 |
| 9/64" | 0.1406 | 3.57 | 11.5 mm | 0.4528 | 11.50 |
| #27 | 0.1440 | 3.66 | 29/64" | 0.4531 | 11.51 |
| #26 | 0.1470 | 3.73 | 15/32" | 0.4688 | 11.91 |
| #25 | 0.1495 | 3.80 | 12 mm | 0.4724 | 12.00 |
| #24 | 0.1520 | 3.86 | 31/64" | 0.4844 | 12.30 |
| #23 | 0.1540 | 3.91 | 12.5 mm | 0.4921 | 12.50 |
| 5/32" | 0.1562 | 3.97 | 1/2" | 0.5000 | 12.70 |
| #22 | 0.1570 | 3.99 | 13 mm | 0.5118 | 13.00 |
| 4 mm | 0.1575 | 4.00 | 17/32" | 0.5312 | 13.49 |
| #21 | 0.1590 | 4.04 | 9/16" | 0.5625 | 14.29 |
| #20 | 0.1610 | 4.09 | 19/32" | 0.5938 | 15.08 |
| 4.2 mm | 0.1654 | 4.20 | 5/8" | 0.6250 | 15.88 |
| #19 | 0.1660 | 4.22 | 21/32" | 0.6562 | 16.67 |
| #18 | 0.1695 | 4.31 | 11/16" | 0.6875 | 17.46 |
| 11/64" | 0.1719 | 4.37 | 23/32" | 0.7188 | 18.26 |
| #17 | 0.1730 | 4.39 | 3/4" | 0.7500 | 19.05 |
| #16 | 0.1770 | 4.50 | 25/32" | 0.7812 | 19.84 |
| 4.5 mm | 0.1772 | 4.50 | 13/16" | 0.8125 | 20.64 |
| #15 | 0.1800 | 4.57 | 27/32" | 0.8438 | 21.43 |
| #14 | 0.1820 | 4.62 | 7/8" | 0.8750 | 22.22 |
| #13 | 0.1850 | 4.70 | 29/32" | 0.9062 | 23.02 |
| 3/16" | 0.1875 | 4.76 | 15/16" | 0.9375 | 23.81 |
| #12 | 0.1890 | 4.80 | 31/32" | 0.9688 | 24.61 |
| #11 | 0.1910 | 4.85 | 1" | 1.0000 | 25.40 |
How to Use This Chart
Reading a callout. A drawing that says "DRILL #7 (.201)" or ".201 DIA" means the same hole. Modern drawings increasingly give the decimal only and let the shop choose the tool; this chart is the translation table in both directions.
Drilled-hole accuracy. A twist drill is a roughing tool. Expect a drilled hole to run 0.002 to 0.005" oversize in most materials, with more variation in deep holes. For a hole with a real diameter tolerance, plan on drilling undersize and reaming or boring to finish, and see our DFM guide for how hole callouts drive cost.
Metric substitution. Because the list is sorted by size, near-equivalents sit next to each other: 6.8 mm (0.2677") lands a thousandth over the letter H (0.2660"), and 3.3 mm (0.1299") falls between #30 and #29. Shops running mixed inch and metric work use these crossovers daily.
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