Reference Only. See Terms of Use.
Fractional Size |
# SIZE |
LETTER |
METRIC |
DECIMAL INCHES |
| #80 | 0.0135 | |||
| #79 | 0.0145 | |||
| 1/64 | 0.0156 | |||
| #78 | 0.0160 | |||
| #77 | 0.0180 | |||
| 0.5mm | 0.0197 | |||
| #76 | 0.0200 | |||
| #75 | 0.0210 | |||
| #74 | 0.0225 | |||
| #73 | 0.0240 | |||
| #72 | 0.0250 | |||
| #71 | 0.0260 | |||
| #70 | 0.0280 | |||
| #69 | 0.0292 | |||
| 0.75mm | 0.0295 | |||
| #68 | 0.0310 | |||
| 1/32 | 0.0312 | |||
| #67 | 0.0320 | |||
| #66 | 0.0330 | |||
| #65 | 0.0350 | |||
| #64 | 0.0360 | |||
| #63 | 0.0370 | |||
| #62 | 0.0380 | |||
| #61 | 0.0390 | |||
| 1mm | 0.0394 | |||
| #60 | 0.0400 | |||
| #59 | 0.0410 | |||
| #58 | 0.0420 | |||
| #57 | 0.0430 | |||
| #56 | 0.0465 | |||
| 3/64 | 0.0469 | |||
| 1.25mm | 0.0492 | |||
| #55 | 0.0520 | |||
| #54 | 0.0550 | |||
| 1.5mm | 0.0591 | |||
| #53 | 0.0595 | |||
| 1/16 | 0.0625 | |||
| #52 | 0.0635 | |||
| #51 | 0.0670 | |||
| 1.75mm | 0.0689 | |||
| #50 | 0.0700 | |||
| #49 | 0.0730 | |||
| #48 | 0.0760 | |||
| 5/64 | 0.0781 | |||
| #47 | 0.0785 | |||
| 2mm | 0.0787 | |||
| #46 | 0.0810 | |||
| #45 | 0.0820 | |||
| #44 | 0.0860 | |||
| 2.25mm | 0.0886 | |||
| #43 | 0.0890 | |||
| #42 | 0.0935 | |||
| 3/32 | 0.0938 | |||
| #41 | 0.0960 | |||
| #40 | 0.0980 | |||
| 2.5mm | 0.0984 | |||
| #39 | 0.0995 | |||
| #38 | 0.1015 | |||
| #37 | 0.1040 | |||
| #36 | 0.1065 | |||
| 2.75mm | 0.1083 | |||
| 7/64 | 0.1094 | |||
| #35 | 0.1100 | |||
| #34 | 0.1110 | |||
| #33 | 0.1130 | |||
| #32 | 0.1160 | |||
| 3mm | 0.1181 | |||
| #31 | 0.1200 | |||
| 1/8 | 0.1250 | |||
| 3.25mm | 0.1280 | |||
| #30 | 0.1285 | |||
| #29 | 0.1360 | |||
| 3.5mm | 0.1378 | |||
| #28 | 0.1405 | |||
| 9/64 | 0.1406 | |||
| #27 | 0.1440 | |||
| #26 | 0.1470 | |||
| 3.75mm | 0.1476 | |||
| #25 | 0.1495 | |||
| #24 | 0.1520 | |||
| #23 | 0.1540 | |||
| 5/32 | 0.1562 | |||
| #22 | 0.1570 | |||
| 4mm | 0.1575 | |||
| #21 | 0.1590 | |||
| #20 | 0.1610 | |||
| #19 | 0.1660 | |||
| 4.25mm | 0.1673 | |||
| #18 | 0.1695 | |||
| 11/64 | 0.1719 | |||
| #17 | 0.1730 | |||
| #16 | 0.1770 | |||
| 4.5mm | 0.1772 | |||
| #15 | 0.1800 | |||
| #14 | 0.1820 | |||
| #13 | 0.1850 | |||
| 4.75mm | 0.1870 | |||
| 3/16 | 0.1875 | |||
| #12 | 0.1890 | |||
| #11 | 0.1910 | |||
| #10 | 0.1935 | |||
| #9 | 0.1960 | |||
| 5mm | 0.1969 | |||
| #8 | 0.1990 | |||
| #7 | 0.2010 | |||
| 13/64 | 0.2031 | |||
| #6 | 0.2040 | |||
| #5 | 0.2055 | |||
| 5.25mm | 0.2067 | |||
| #4 | 0.2090 | |||
| #3 | 0.2130 | |||
| 5.5mm | 0.2165 | |||
| 7/32 | 0.2188 | |||
| #2 | 0.2210 | |||
| 5.75mm | 0.2264 | |||
| #1 | 0.2280 | |||
| A | 0.2340 | |||
| 15/64 | 0.2344 | |||
| 6mm | 0.2362 | |||
| B | 0.2380 | |||
| C | 0.2420 | |||
| D | 0.2460 | |||
| 6.25mm | 0.2461 | |||
| 1/4 | E | 0.2500 | ||
| 6.5mm | 0.2559 | |||
| F | 0.2570 | |||
| G | 0.2610 | |||
| 17/64 | 0.2656 | |||
| 6.75mm | 0.2657 | |||
| H | 0.2660 | |||
| I | 0.2720 | |||
| 7mm | 0.2756 | |||
| J | 0.2770 | |||
| K | 0.2810 | |||
| 9/32 | 0.2812 | |||
| 7.25mm | 0.2854 | |||
| L | 0.2900 | |||
| M | 0.2950 | |||
| 7.5mm | 0.2953 | |||
| 19/64 | 0.2969 | |||
| N | 0.3020 | |||
| 7.75mm | 0.3051 | |||
| 5/16 | 0.3125 | |||
| 8mm | 0.3150 | |||
| O | 0.3160 | |||
| P | 0.3230 | |||
| 8.25mm | 0.3248 | |||
| 21/64 | 0.3281 | |||
| Q | 0.3320 | |||
| 8.5mm | 0.3346 | |||
| R | 0.3390 | |||
| 11/32 | 0.3438 | |||
| 8.75mm | 0.3445 | |||
| S | 0.3480 | |||
| 9mm | 0.3543 | |||
| T | 0.3580 | |||
| 23/64 | 0.3594 | |||
| 9.25mm | 0.3642 | |||
| U | 0.3680 | |||
| 9.5mm | 0.3740 | |||
| 3/8 | 0.3750 | |||
| V | 0.3770 | |||
| 9.75mm | 0.3839 | |||
| W | 0.3860 | |||
| 25/64 | 0.3906 | |||
| 10mm | 0.3937 | |||
| X | 0.3970 | |||
| Y | 0.4040 | |||
| 13/32 | 0.4063 | |||
| Z | 0.4130 | |||
| 10.5mm | 0.4134 | |||
| 27/64 | 0.4219 | |||
| 11mm | 0.4331 | |||
| 7/16 | 0.4375 | |||
| 11.5mm | 0.4528 | |||
| 29/64 | 0.4531 | |||
| 15/32 | 0.4688 | |||
| 12mm | 0.4724 | |||
| 31/64 | 0.4844 | |||
| 12.5mm | 0.4921 | |||
| 1/2 | 0.5000 | |||
| 13mm | 0.5118 | |||
| 33/64 | 0.5156 | |||
| 17/32 | 0.5312 | |||
| 13.5mm | 0.5315 | |||
| 35/64 | 0.5469 | |||
| 14mm | 0.5512 | |||
| 9/16 | 0.5625 | |||
| 14.5mm | 0.5709 | |||
| 37/64 | 0.5781 | |||
| 15mm | 0.5906 | |||
| 19/32 | 0.5938 | |||
| 39/64 | 0.6094 | |||
| 15.5mm | 0.6102 | |||
| 5/8 | 0.6250 | |||
| 16mm | 0.6299 | |||
| 41/64 | 0.6406 | |||
| 16.5mm | 0.6496 | |||
| 21/32 | 0.6562 | |||
| 17mm | 0.6693 | |||
| 43/64 | 0.6719 | |||
| 11/16 | 0.6875 | |||
| 17.5mm | 0.6890 | |||
| 45/64 | 0.7031 | |||
| 18mm | 0.7087 | |||
| 23/32 | 0.7188 | |||
| 18.5mm | 0.7283 | |||
| 47/64 | 0.7344 | |||
| 19mm | 0.7480 | |||
| 3/4 | 0.7500 | |||
| 49/64 | 0.7656 | |||
| 19.5mm | 0.7677 | |||
| 25/32 | 0.7813 | |||
| 20mm | 0.7874 | |||
| 51/64 | 0.7969 | |||
| 20.5mm | 0.8071 | |||
| 13/16 | 0.8125 | |||
| 21mm | 0.8268 | |||
| 53/64 | 0.8281 | |||
| 27/32 | 0.8438 | |||
| 21.5mm | 0.8465 | |||
| 55/64 | 0.8594 | |||
| 22mm | 0.8661 | |||
| 7/8 | 0.8750 | |||
| 22.5mm | 0.8858 | |||
| 57/64 | 0.8906 | |||
| 23mm | 0.9055 | |||
| 29/32 | 0.9062 | |||
| 59/64 | 0.9219 | |||
| 23.5mm | 0.9252 | |||
| 15/16 | 0.9375 | |||
| 24mm | 0.9449 | |||
| 61/64 | 0.9531 | |||
| 24.5mm | 0.9646 | |||
| 31/32 | 0.9688 | |||
| 25mm | 0.9843 | |||
| 63/64 | 0.9844 | |||
| 1 inch | 1.0000 |
For design, see:
- ASME B94.11 – Twist Drills
- This Standard covers nomenclature, definitions, sizes and tolerances of High Speed Steel, Straight and Taper Shank Drills, and Combined Drills and Countersinks, Plain and Bell Type. It covers both inch and metric size drills.
- ASME B18.2.8 – Clearance holes for bolts, screws and studs
- This Standard covers the recommended clearance hole sizes for #0 through 1.5 in. and M1.6 through M100 metric fasteners in three classes of clearance using a close-, normal-, and loose-fit category.
