Drill Size Conversion Table
This table is the chart for converting and identifying various drill bit sizes. Because of differences in numbering systems, some conversions are approximated but are within .0001 inch. If all else fails, you may want to use our Tap Drill Size Calculator. The information available from our sources is usually sufficient for all computer related drill or screw requirements world wide.
|
Fract. (in) | Decimal | Wire No. /Letter | Metric (mm) |
|
Fract. (in) | Decimal | Wire No. /Letter | Metric (mm) |
|
Fract. (in) | Decimal | Wire No. /Letter | Metric (mm) |
|
| 0.0098 | | 0.25 |
| 0.1065 | 36 | |
| 0.3480 | S | |
| 0.0118 | | 0.30 |
7/64 | 0.1094 | | |
| 0.3543 | | 9.00 |
| 0.0135 | 80 | |
| 0.1100 | 35 | |
| 0.3580 | T | |
| 0.0138 | | 0.35 |
| 0.1102 | | 2.80 |
23/64 | 0.3594 | | |
| 0.0145 | 79 | |
| 0.1110 | 34 | |
| 0.3680 | U | |
1/64 | 0.0156 | | |
| 0.1130 | 33 | |
| 0.3740 | | 9.50 |
| 0.0157 | | 0.40 |
| 0.1142 | | 2.90 |
3/8 | 0.3750 | | |
| 0.0160 | 78 | |
| 0.1160 | 32 | |
| 0.3770 | V | |
| 0.0177 | | 0.45 |
| 0.1181 | | 3.00 |
| 0.3860 | W | |
| 0.0180 | 77 | |
| 0.1200 | 31 | |
25/64 | 0.3906 | | |
| 0.0197 | | 0.50 |
1/8 | 0.1250 | | |
| 0.3937 | | 10.00 |
| 0.0200 | 76 | |
| 0.1285 | 30 | |
| 0.3970 | X | |
| 0.0210 | 75 | |
| 0.1360 | 29 | |
| 0.4040 | Y | |
| 0.0217 | | 0.55 |
| 0.1378 | | 3.50 |
13/32 | 0.4063 | | |
| 0.0225 | 74 | |
| 0.1405 | 28 | |
| 0.4130 | Z | |
| 0.0236 | | 0.60 |
9/64 | 0.1406 | | |
| 0.4134 | | 10.50 |
| 0.0240 | 73 | |
| 0.1440 | 27 | |
27/64 | 0.4219 | | |
| 0.0250 | 72 | |
| 0.1470 | 26 | |
| 0.4331 | | 11.00 |
| 0.0256 | | 0.65 |
| 0.1495 | 25 | |
7/16 | 0.4375 | | |
| 0.0260 | 71 | |
| 0.1520 | 24 | |
| 0.4528 | | 11.50 |
| 0.0276 | | 0.70 |
| 0.1540 | 23 | |
29/64 | 0.4531 | | |
| 0.0280 | 70 | |
5/32 | 0.1563 | | |
15/32 | 0.4688 | | |
| 0.0292 | 69 | |
| 0.1570 | 22 | |
| 0.4724 | | 12.00 |
| 0.0295 | | 0.75 |
| 0.1575 | | 4.00 |
31/64 | 0.4844 | | |
| 0.0310 | 68 | |
| 0.1590 | 21 | |
| 0.4921 | | 12.50 |
1/32 | 0.0313 | | |
| 0.1610 | 20 | |
1/2 | 0.5000 | | |
| 0.0315 | | 0.80 |
| 0.1660 | 19 | |
| 0.5118 | | 13.00 |
| 0.0320 | 67 | |
| 0.1695 | 18 | |
33/64 | 0.5156 | | |
| 0.0330 | 66 | |
11/64 | 0.1719 | | |
17/32 | 0.5313 | | |
| 0.0335 | | 0.85 |
| 0.1730 | 17 | |
| 0.5315 | | 13.50 |
| 0.0350 | 65 | |
| 0.1770 | 16 | |
35/64 | 0.5469 | | |
| 0.0354 | | 0.90 |
| 0.1772 | | 4.50 |
| 0.5512 | | 14.00 |
| 0.0360 | 64 | |
| 0.1800 | 15 | |
9/16 | 0.5625 | | |
| 0.0370 | 63 | |
| 0.1820 | 14 | |
| 0.5709 | | 14.50 |
| 0.0374 | | 0.95 |
| 0.1850 | 13 | |
37/64 | 0.5781 | | |
| 0.0380 | 62 | |
3/16 | 0.1875 | | |
| 0.5905 | | 15.00 |
| 0.0390 | 61 | |
| 0.1890 | 12 | |
19/32 | 0.5938 | | |
| 0.0394 | | 1.00 |
| 0.1910 | 11 | |
39/64 | 0.6094 | | |
| 0.0400 | 60 | |
| 0.1935 | 10 | |
| 0.6102 | | 15.50 |
| 0.0410 | 59 | |
| 0.1960 | 9 | |
5/8 | 0.6250 | | |
| 0.0420 | 58 | |
| 0.1968 | | 5.00 |
| 0.6299 | | 16.00 |
| 0.0430 | 57 | |
| 0.1990 | 8 | |
41/64 | 0.6406 | | |
| 0.0433 | | 1.10 |
| 0.2010 | 7 | |
| 0.6496 | | 16.50 |
| 0.0465 | 56 | |
13/64 | 0.2031 | | |
21/32 | 0.6563 | | |
3/64 | 0.0469 | | |
| 0.2040 | 6 | |
| 0.6693 | | 17.00 |
| 0.0472 | | 1.20 |
| 0.2055 | 5 | |
43/64 | 0.6719 | | |
| 0.0512 | | 1.30 |
| 0.2090 | 4 | |
11/16 | 0.6875 | | |
| 0.0520 | 55 | |
| 0.2130 | 3 | |
| 0.6890 | | 17.50 |
| 0.0550 | 54 | |
| 0.2165 | | 5.50 |
45/64 | 0.7031 | | |
| 0.0551 | | 1.40 |
7/32 | 0.2188 | | |
| 0.7087 | | 18.00 |
| 0.0591 | | 1.50 |
| 0.2210 | 2 | |
23/32 | 0.7188 | | |
| 0.0595 | 53 | |
| 0.2280 | 1 | |
| 0.7283 | | 18.50 |
1/16 | 0.0625 | | |
| 0.2340 | A | |
47/64 | 0.7344 | | |
| 0.0630 | | 1.60 |
15/64 | 0.2344 | | |
| 0.7480 | | 19.00 |
| 0.0635 | 52 | |
| 0.2362 | | 6.00 |
3/4 | 0.7500 | | |
| 0.0669 | | 1.70 |
| 0.2380 | B | |
49/64 | 0.7656 | | |
| 0.0670 | 51 | |
| 0.2420 | C | |
| 0.7677 | | 19.50 |
| 0.0700 | 50 | |
| 0.2460 | D | |
25/32 | 0.7813 | | |
| 0.0709 | | 1.80 |
1/4 | 0.2500 | E | |
| 0.7874 | | 20.00 |
| 0.0730 | 49 | |
| 0.2559 | | 6.50 |
51/64 | 0.7969 | | |
| 0.0748 | | 1.90 |
| 0.2570 | F | |
| 0.8071 | | 20.50 |
| 0.0760 | 48 | |
| 0.2610 | G | |
13/16 | 0.8125 | | |
5/64 | 0.0781 | | |
17/64 | 0.2656 | | |
| 0.8268 | | 21.00 |
| 0.0785 | 47 | |
| 0.2660 | H | |
53/64 | 0.8281 | | |
| 0.0787 | | 2.00 |
| 0.2720 | I | |
27/32 | 0.8438 | | |
| 0.0810 | 46 | |
| 0.2756 | | 7.00 |
| 0.8465 | | 21.50 |
| 0.0820 | 45 | |
| 0.2770 | J | |
55/64 | 0.8594 | | |
| 0.0827 | | 2.10 |
| 0.2810 | K | |
| 0.8661 | | 22.00 |
| 0.0860 | 44 | |
9/32 | 0.2813 | | |
7/8 | 0.8750 | | |
| 0.0866 | | 2.20 |
| 0.2900 | L | |
| 0.8858 | | 22.50 |
| 0.0890 | 43 | |
| 0.2950 | M | |
57/64 | 0.8906 | | |
| 0.0906 | | 2.30 |
| 0.2953 | | 7.50 |
| 0.9055 | | 23.00 |
| 0.0935 | 42 | |
19/64 | 0.2969 | | |
29/32 | 0.9063 | | |
3/32 | 0.0938 | | |
| 0.3020 | N | |
59/64 | 0.9219 | | |
| 0.0945 | | 2.40 |
5/16 | 0.3125 | | |
| 0.9252 | | 23.50 |
| 0.0960 | 41 | |
| 0.3150 | | 8.00 |
15/16 | 0.9375 | | |
| 0.0980 | 40 | |
| 0.3160 | O | |
| 0.9449 | | 24.00 |
| 0.0984 | | 2.50 |
| 0.3230 | P | |
61/64 | 0.9531 | | |
| 0.0995 | 39 | |
21/64 | 0.3281 | | |
| 0.9646 | | 24.50 |
| 0.1015 | 38 | |
| 0.3320 | Q | |
31/32 | 0.9688 | | |
| 0.1024 | | 2.60 |
| 0.3346 | | 8.50 |
| 0.9842 | | 25.00 |
| 0.1040 | 37 | |
| 0.3390 | R | |
63/64 | 0.9844 | | |
| 0.1063 | | 2.70 |
11/32 | 0.3438 | | |
1 | 1.0000 | | |
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Fract. (in) | Decimal | Wire No. /Letter | Metric (mm) |
Fract. (in) | Decimal | Wire No. /Letter | Metric (mm) |
Fract. (in) | Decimal | Wire No. /Letter | Metric (mm) |
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