Decimal / Fraction Converter
Convert between fractional inches, decimal inches, and millimeters. Includes complete drill size chart.
Unit Converter
Fraction top
Fraction bottom
Decimal inches
mm
Drill Size Chart
Wire gauge, letter, and fractional sizes — sorted by decimal size
| Size | Decimal (in) | Metric (mm) |
|---|---|---|
| #80 | 0.0135 | 0.343 |
| #79 | 0.0145 | 0.368 |
| 1/64 | 0.0156 | 0.397 |
| #78 | 0.0160 | 0.406 |
| #77 | 0.0180 | 0.457 |
| #76 | 0.0200 | 0.508 |
| #75 | 0.0210 | 0.533 |
| #74 | 0.0225 | 0.571 |
| #73 | 0.0240 | 0.610 |
| #72 | 0.0250 | 0.635 |
| #71 | 0.0260 | 0.660 |
| #70 | 0.0280 | 0.711 |
| #69 | 0.0292 | 0.742 |
| #68 | 0.0310 | 0.787 |
| 1/32 | 0.0313 | 0.794 |
| #67 | 0.0320 | 0.813 |
| #66 | 0.0330 | 0.838 |
| #65 | 0.0350 | 0.889 |
| #64 | 0.0360 | 0.914 |
| #63 | 0.0370 | 0.940 |
| #62 | 0.0380 | 0.965 |
| #61 | 0.0390 | 0.991 |
| #60 | 0.0400 | 1.016 |
| #59 | 0.0410 | 1.041 |
| #58 | 0.0420 | 1.067 |
| #57 | 0.0430 | 1.092 |
| #56 | 0.0465 | 1.181 |
| 3/64 | 0.0469 | 1.191 |
| #55 | 0.0520 | 1.321 |
| #54 | 0.0550 | 1.397 |
| #53 | 0.0595 | 1.511 |
| 1/16 | 0.0625 | 1.587 |
| #52 | 0.0635 | 1.613 |
| #51 | 0.0670 | 1.702 |
| #50 | 0.0700 | 1.778 |
| #49 | 0.0730 | 1.854 |
| #48 | 0.0760 | 1.930 |
| 5/64 | 0.0781 | 1.984 |
| #47 | 0.0785 | 1.994 |
| #46 | 0.0810 | 2.057 |
| #45 | 0.0820 | 2.083 |
| #44 | 0.0860 | 2.184 |
| #43 | 0.0890 | 2.261 |
| #42 | 0.0935 | 2.375 |
| 3/32 | 0.0938 | 2.381 |
| #41 | 0.0960 | 2.438 |
| #40 | 0.0980 | 2.489 |
| #39 | 0.0995 | 2.527 |
| #38 | 0.1015 | 2.578 |
| #37 | 0.1040 | 2.642 |
| #36 | 0.1065 | 2.705 |
| 7/64 | 0.1094 | 2.778 |
| #35 | 0.1100 | 2.794 |
| #34 | 0.1110 | 2.819 |
| #33 | 0.1130 | 2.870 |
| #32 | 0.1160 | 2.946 |
| #31 | 0.1200 | 3.048 |
| 1/8 | 0.1250 | 3.175 |
| #30 | 0.1285 | 3.264 |
| #29 | 0.1360 | 3.454 |
| #28 | 0.1405 | 3.569 |
| 9/64 | 0.1406 | 3.572 |
| #27 | 0.1440 | 3.658 |
| #26 | 0.1470 | 3.734 |
| #25 | 0.1495 | 3.797 |
| #24 | 0.1520 | 3.861 |
| #23 | 0.1540 | 3.912 |
| 5/32 | 0.1563 | 3.969 |
| #22 | 0.1570 | 3.988 |
| #21 | 0.1590 | 4.039 |
| #20 | 0.1610 | 4.089 |
| #19 | 0.1660 | 4.216 |
| #18 | 0.1695 | 4.305 |
| 11/64 | 0.1719 | 4.366 |
| #17 | 0.1730 | 4.394 |
| #16 | 0.1770 | 4.496 |
| #15 | 0.1800 | 4.572 |
| #14 | 0.1820 | 4.623 |
| #13 | 0.1850 | 4.699 |
| 3/16 | 0.1875 | 4.762 |
| #12 | 0.1890 | 4.801 |
| #11 | 0.1910 | 4.851 |
| #10 | 0.1935 | 4.915 |
| #9 | 0.1960 | 4.978 |
| #8 | 0.1990 | 5.055 |
| #7 | 0.2010 | 5.105 |
| 13/64 | 0.2031 | 5.159 |
| #6 | 0.2040 | 5.182 |
| #5 | 0.2055 | 5.220 |
| #4 | 0.2090 | 5.309 |
| #3 | 0.2130 | 5.410 |
| 7/32 | 0.2188 | 5.556 |
| #2 | 0.2210 | 5.613 |
| #1 | 0.2280 | 5.791 |
| A | 0.2340 | 5.944 |
| 15/64 | 0.2344 | 5.953 |
| B | 0.2380 | 6.045 |
| C | 0.2420 | 6.147 |
| D | 0.2460 | 6.248 |
| E | 0.2500 | 6.350 |
| 1/4 | 0.2500 | 6.350 |
| F | 0.2570 | 6.528 |
| G | 0.2610 | 6.629 |
| 17/64 | 0.2656 | 6.747 |
| H | 0.2660 | 6.756 |
| I | 0.2720 | 6.909 |
| J | 0.2770 | 7.036 |
| K | 0.2810 | 7.137 |
| 9/32 | 0.2813 | 7.144 |
| L | 0.2900 | 7.366 |
| M | 0.2950 | 7.493 |
| 19/64 | 0.2969 | 7.541 |
| N | 0.3020 | 7.671 |
| 5/16 | 0.3125 | 7.938 |
| O | 0.3160 | 8.026 |
| P | 0.3230 | 8.204 |
| 21/64 | 0.3281 | 8.334 |
| Q | 0.3320 | 8.433 |
| R | 0.3390 | 8.611 |
| 11/32 | 0.3438 | 8.731 |
| S | 0.3480 | 8.839 |
| T | 0.3580 | 9.093 |
| 23/64 | 0.3594 | 9.128 |
| U | 0.3680 | 9.347 |
| 3/8 | 0.3750 | 9.525 |
| V | 0.3770 | 9.576 |
| W | 0.3860 | 9.804 |
| 25/64 | 0.3906 | 9.922 |
| X | 0.3970 | 10.084 |
| Y | 0.4040 | 10.262 |
| 13/32 | 0.4063 | 10.319 |
| Z | 0.4130 | 10.490 |
| 27/64 | 0.4219 | 10.716 |
| 7/16 | 0.4375 | 11.112 |
| 29/64 | 0.4531 | 11.509 |
| 15/32 | 0.4688 | 11.906 |
| 31/64 | 0.4844 | 12.303 |
| 1/2 | 0.5000 | 12.700 |
| 33/64 | 0.5156 | 13.097 |
| 17/32 | 0.5313 | 13.494 |
| 35/64 | 0.5469 | 13.891 |
| 9/16 | 0.5625 | 14.287 |
| 37/64 | 0.5781 | 14.684 |
| 19/32 | 0.5938 | 15.081 |
| 39/64 | 0.6094 | 15.478 |
| 5/8 | 0.6250 | 15.875 |
| 41/64 | 0.6406 | 16.272 |
| 21/32 | 0.6563 | 16.669 |
| 43/64 | 0.6719 | 17.066 |
| 11/16 | 0.6875 | 17.462 |
| 45/64 | 0.7031 | 17.859 |
| 23/32 | 0.7188 | 18.256 |
| 47/64 | 0.7344 | 18.653 |
| 3/4 | 0.7500 | 19.050 |
| 49/64 | 0.7656 | 19.447 |
| 25/32 | 0.7813 | 19.844 |
| 51/64 | 0.7969 | 20.241 |
| 13/16 | 0.8125 | 20.637 |
| 53/64 | 0.8281 | 21.034 |
| 27/32 | 0.8438 | 21.431 |
| 55/64 | 0.8594 | 21.828 |
| 7/8 | 0.8750 | 22.225 |
| 57/64 | 0.8906 | 22.622 |
| 29/32 | 0.9063 | 23.019 |
| 59/64 | 0.9219 | 23.416 |
| 15/16 | 0.9375 | 23.813 |
| 61/64 | 0.9531 | 24.209 |
| 31/32 | 0.9688 | 24.606 |
| 63/64 | 0.9844 | 25.003 |
| 1 | 1.0000 | 25.400 |
170 of 170 sizes shown
Important Disclaimer
This tool is provided for educational and reference purposes only. Always verify all calculations against FAA-approved maintenance manuals, aircraft documentation, and applicable regulations. Never use web-based tools as the sole basis for airworthiness decisions.