---
type: "chart"
name: "Drill size chart"
drill_count: 397
series_count: 4
ordering: "ascending diameter"
standard: "ANSI/ASME B94.11M; BS 328"
verified: "August 1, 2026"
url: https://shopmath.org/charts/drill-sizes
---

# Drill Size Chart — Number, Letter, Fractional and Metric by Diameter

All 397 standard twist drill sizes in one continuous ascending-diameter order, with inch and millimetre on every row. Number, letter, fractional and metric sizes interleave rather than sitting in four separate tables, which is what makes "the next size up from a #7" a one-glance answer.

## Series Covered

| Series | Sizes with pages | Range (in) | Range (mm) |
| --- | --- | --- | --- |
| Fractional Drill Sizes | 64 | 0.0156 – 1.0000 in | 0.397 – 25.400 mm |
| Letter Drill Sizes | 26 | 0.2340 – 0.4130 in | 5.944 – 10.490 mm |
| Metric Drill Sizes | 227 | 0.0079 – 0.9843 in | 0.200 – 25.000 mm |
| Number Drill Sizes | 60 | 0.0400 – 0.2280 in | 1.016 – 5.791 mm |

## Every Standard Drill Size by Diameter

Ascending diameter. Linked sizes have their own page with equivalents in the other series and the threads they tap.

| Drill | Series | Diameter (in) | Diameter (mm) | Fraction |
| --- | --- | --- | --- | --- |
| [0.2 mm](https://shopmath.org/drills/metric/0-2mm.md) | Metric | 0.0079 | 0.200 |  |
| [0.22 mm](https://shopmath.org/drills/metric/0-22mm.md) | Metric | 0.0087 | 0.220 |  |
| [0.25 mm](https://shopmath.org/drills/metric/0-25mm.md) | Metric | 0.0098 | 0.250 |  |
| [0.28 mm](https://shopmath.org/drills/metric/0-28mm.md) | Metric | 0.0110 | 0.280 |  |
| [0.3 mm](https://shopmath.org/drills/metric/0-3mm.md) | Metric | 0.0118 | 0.300 |  |
| [0.32 mm](https://shopmath.org/drills/metric/0-32mm.md) | Metric | 0.0126 | 0.320 |  |
| #80 | Number | 0.0135 | 0.343 |  |
| [0.35 mm](https://shopmath.org/drills/metric/0-35mm.md) | Metric | 0.0138 | 0.350 |  |
| #79 | Number | 0.0145 | 0.368 |  |
| [0.38 mm](https://shopmath.org/drills/metric/0-38mm.md) | Metric | 0.0150 | 0.380 |  |
| [1/64](https://shopmath.org/drills/fractional/1-64.md) | Fractional | 0.0156 | 0.397 | 1/64 |
| [0.4 mm](https://shopmath.org/drills/metric/0-4mm.md) | Metric | 0.0157 | 0.400 |  |
| #78 | Number | 0.0160 | 0.406 |  |
| [0.42 mm](https://shopmath.org/drills/metric/0-42mm.md) | Metric | 0.0165 | 0.420 |  |
| [0.45 mm](https://shopmath.org/drills/metric/0-45mm.md) | Metric | 0.0177 | 0.450 |  |
| #77 | Number | 0.0180 | 0.457 |  |
| [0.48 mm](https://shopmath.org/drills/metric/0-48mm.md) | Metric | 0.0189 | 0.480 |  |
| [0.5 mm](https://shopmath.org/drills/metric/0-5mm.md) | Metric | 0.0197 | 0.500 |  |
| #76 | Number | 0.0200 | 0.508 |  |
| [0.52 mm](https://shopmath.org/drills/metric/0-52mm.md) | Metric | 0.0205 | 0.520 |  |
| #75 | Number | 0.0210 | 0.533 |  |
| [0.55 mm](https://shopmath.org/drills/metric/0-55mm.md) | Metric | 0.0217 | 0.550 |  |
| #74 | Number | 0.0225 | 0.572 |  |
| [0.58 mm](https://shopmath.org/drills/metric/0-58mm.md) | Metric | 0.0228 | 0.580 |  |
| [0.6 mm](https://shopmath.org/drills/metric/0-6mm.md) | Metric | 0.0236 | 0.600 |  |
| #73 | Number | 0.0240 | 0.610 |  |
| [0.62 mm](https://shopmath.org/drills/metric/0-62mm.md) | Metric | 0.0244 | 0.620 |  |
| #72 | Number | 0.0250 | 0.635 |  |
| [0.65 mm](https://shopmath.org/drills/metric/0-65mm.md) | Metric | 0.0256 | 0.650 |  |
| #71 | Number | 0.0260 | 0.660 |  |
| [0.68 mm](https://shopmath.org/drills/metric/0-68mm.md) | Metric | 0.0268 | 0.680 |  |
| [0.7 mm](https://shopmath.org/drills/metric/0-7mm.md) | Metric | 0.0276 | 0.700 |  |
| #70 | Number | 0.0280 | 0.711 |  |
| [0.72 mm](https://shopmath.org/drills/metric/0-72mm.md) | Metric | 0.0283 | 0.720 |  |
| #69 | Number | 0.0292 | 0.742 |  |
| [0.75 mm](https://shopmath.org/drills/metric/0-75mm.md) | Metric | 0.0295 | 0.750 |  |
| [0.78 mm](https://shopmath.org/drills/metric/0-78mm.md) | Metric | 0.0307 | 0.780 |  |
| #68 | Number | 0.0310 | 0.787 |  |
| [1/32](https://shopmath.org/drills/fractional/1-32.md) | Fractional | 0.0313 | 0.794 | 1/32 |
| [0.8 mm](https://shopmath.org/drills/metric/0-8mm.md) | Metric | 0.0315 | 0.800 |  |
| #67 | Number | 0.0320 | 0.813 |  |
| [0.82 mm](https://shopmath.org/drills/metric/0-82mm.md) | Metric | 0.0323 | 0.820 |  |
| #66 | Number | 0.0330 | 0.838 |  |
| [0.85 mm](https://shopmath.org/drills/metric/0-85mm.md) | Metric | 0.0335 | 0.850 |  |
| [0.88 mm](https://shopmath.org/drills/metric/0-88mm.md) | Metric | 0.0346 | 0.880 |  |
| #65 | Number | 0.0350 | 0.889 |  |
| [0.9 mm](https://shopmath.org/drills/metric/0-9mm.md) | Metric | 0.0354 | 0.900 |  |
| #64 | Number | 0.0360 | 0.914 |  |
| [0.92 mm](https://shopmath.org/drills/metric/0-92mm.md) | Metric | 0.0362 | 0.920 |  |
| #63 | Number | 0.0370 | 0.940 |  |
| [0.95 mm](https://shopmath.org/drills/metric/0-95mm.md) | Metric | 0.0374 | 0.950 |  |
| #62 | Number | 0.0380 | 0.965 |  |
| [0.98 mm](https://shopmath.org/drills/metric/0-98mm.md) | Metric | 0.0386 | 0.980 |  |
| #61 | Number | 0.0390 | 0.991 |  |
| [1 mm](https://shopmath.org/drills/metric/1mm.md) | Metric | 0.0394 | 1.000 |  |
| [#60](https://shopmath.org/drills/number/60.md) | Number | 0.0400 | 1.016 |  |
| [#59](https://shopmath.org/drills/number/59.md) | Number | 0.0410 | 1.041 |  |
| [1.05 mm](https://shopmath.org/drills/metric/1-05mm.md) | Metric | 0.0413 | 1.050 |  |
| [#58](https://shopmath.org/drills/number/58.md) | Number | 0.0420 | 1.067 |  |
| [#57](https://shopmath.org/drills/number/57.md) | Number | 0.0430 | 1.092 |  |
| [1.1 mm](https://shopmath.org/drills/metric/1-1mm.md) | Metric | 0.0433 | 1.100 |  |
| [1.15 mm](https://shopmath.org/drills/metric/1-15mm.md) | Metric | 0.0453 | 1.150 |  |
| [#56](https://shopmath.org/drills/number/56.md) | Number | 0.0465 | 1.181 |  |
| [3/64](https://shopmath.org/drills/fractional/3-64.md) | Fractional | 0.0469 | 1.191 | 3/64 |
| [1.2 mm](https://shopmath.org/drills/metric/1-2mm.md) | Metric | 0.0472 | 1.200 |  |
| [1.25 mm](https://shopmath.org/drills/metric/1-25mm.md) | Metric | 0.0492 | 1.250 |  |
| [1.3 mm](https://shopmath.org/drills/metric/1-3mm.md) | Metric | 0.0512 | 1.300 |  |
| [#55](https://shopmath.org/drills/number/55.md) | Number | 0.0520 | 1.321 |  |
| [1.35 mm](https://shopmath.org/drills/metric/1-35mm.md) | Metric | 0.0532 | 1.350 |  |
| [#54](https://shopmath.org/drills/number/54.md) | Number | 0.0550 | 1.397 |  |
| [1.4 mm](https://shopmath.org/drills/metric/1-4mm.md) | Metric | 0.0551 | 1.400 |  |
| [1.45 mm](https://shopmath.org/drills/metric/1-45mm.md) | Metric | 0.0571 | 1.450 |  |
| [1.5 mm](https://shopmath.org/drills/metric/1-5mm.md) | Metric | 0.0591 | 1.500 |  |
| [#53](https://shopmath.org/drills/number/53.md) | Number | 0.0595 | 1.511 |  |
| [1.55 mm](https://shopmath.org/drills/metric/1-55mm.md) | Metric | 0.0610 | 1.550 |  |
| [1/16](https://shopmath.org/drills/fractional/1-16.md) | Fractional | 0.0625 | 1.587 | 1/16 |
| [1.6 mm](https://shopmath.org/drills/metric/1-6mm.md) | Metric | 0.0630 | 1.600 |  |
| [#52](https://shopmath.org/drills/number/52.md) | Number | 0.0635 | 1.613 |  |
| [1.65 mm](https://shopmath.org/drills/metric/1-65mm.md) | Metric | 0.0650 | 1.650 |  |
| [1.7 mm](https://shopmath.org/drills/metric/1-7mm.md) | Metric | 0.0669 | 1.700 |  |
| [#51](https://shopmath.org/drills/number/51.md) | Number | 0.0670 | 1.702 |  |
| [1.75 mm](https://shopmath.org/drills/metric/1-75mm.md) | Metric | 0.0689 | 1.750 |  |
| [#50](https://shopmath.org/drills/number/50.md) | Number | 0.0700 | 1.778 |  |
| [1.8 mm](https://shopmath.org/drills/metric/1-8mm.md) | Metric | 0.0709 | 1.800 |  |
| [1.85 mm](https://shopmath.org/drills/metric/1-85mm.md) | Metric | 0.0728 | 1.850 |  |
| [#49](https://shopmath.org/drills/number/49.md) | Number | 0.0730 | 1.854 |  |
| [1.9 mm](https://shopmath.org/drills/metric/1-9mm.md) | Metric | 0.0748 | 1.900 |  |
| [#48](https://shopmath.org/drills/number/48.md) | Number | 0.0760 | 1.930 |  |
| [1.95 mm](https://shopmath.org/drills/metric/1-95mm.md) | Metric | 0.0768 | 1.950 |  |
| [5/64](https://shopmath.org/drills/fractional/5-64.md) | Fractional | 0.0781 | 1.984 | 5/64 |
| [#47](https://shopmath.org/drills/number/47.md) | Number | 0.0785 | 1.994 |  |
| [2 mm](https://shopmath.org/drills/metric/2mm.md) | Metric | 0.0787 | 2.000 |  |
| [2.05 mm](https://shopmath.org/drills/metric/2-05mm.md) | Metric | 0.0807 | 2.050 |  |
| [#46](https://shopmath.org/drills/number/46.md) | Number | 0.0810 | 2.057 |  |
| [#45](https://shopmath.org/drills/number/45.md) | Number | 0.0820 | 2.083 |  |
| [2.1 mm](https://shopmath.org/drills/metric/2-1mm.md) | Metric | 0.0827 | 2.100 |  |
| [2.15 mm](https://shopmath.org/drills/metric/2-15mm.md) | Metric | 0.0846 | 2.150 |  |
| [#44](https://shopmath.org/drills/number/44.md) | Number | 0.0860 | 2.184 |  |
| [2.2 mm](https://shopmath.org/drills/metric/2-2mm.md) | Metric | 0.0866 | 2.200 |  |
| [2.25 mm](https://shopmath.org/drills/metric/2-25mm.md) | Metric | 0.0886 | 2.250 |  |
| [#43](https://shopmath.org/drills/number/43.md) | Number | 0.0890 | 2.261 |  |
| [2.3 mm](https://shopmath.org/drills/metric/2-3mm.md) | Metric | 0.0906 | 2.300 |  |
| [2.35 mm](https://shopmath.org/drills/metric/2-35mm.md) | Metric | 0.0925 | 2.350 |  |
| [#42](https://shopmath.org/drills/number/42.md) | Number | 0.0935 | 2.375 |  |
| [3/32](https://shopmath.org/drills/fractional/3-32.md) | Fractional | 0.0938 | 2.381 | 3/32 |
| [2.4 mm](https://shopmath.org/drills/metric/2-4mm.md) | Metric | 0.0945 | 2.400 |  |
| [#41](https://shopmath.org/drills/number/41.md) | Number | 0.0960 | 2.438 |  |
| [2.45 mm](https://shopmath.org/drills/metric/2-45mm.md) | Metric | 0.0965 | 2.450 |  |
| [#40](https://shopmath.org/drills/number/40.md) | Number | 0.0980 | 2.489 |  |
| [2.5 mm](https://shopmath.org/drills/metric/2-5mm.md) | Metric | 0.0984 | 2.500 |  |
| [#39](https://shopmath.org/drills/number/39.md) | Number | 0.0995 | 2.527 |  |
| [2.55 mm](https://shopmath.org/drills/metric/2-55mm.md) | Metric | 0.1004 | 2.550 |  |
| [#38](https://shopmath.org/drills/number/38.md) | Number | 0.1015 | 2.578 |  |
| [2.6 mm](https://shopmath.org/drills/metric/2-6mm.md) | Metric | 0.1024 | 2.600 |  |
| [#37](https://shopmath.org/drills/number/37.md) | Number | 0.1040 | 2.642 |  |
| [2.65 mm](https://shopmath.org/drills/metric/2-65mm.md) | Metric | 0.1043 | 2.650 |  |
| [2.7 mm](https://shopmath.org/drills/metric/2-7mm.md) | Metric | 0.1063 | 2.700 |  |
| [#36](https://shopmath.org/drills/number/36.md) | Number | 0.1065 | 2.705 |  |
| [2.75 mm](https://shopmath.org/drills/metric/2-75mm.md) | Metric | 0.1083 | 2.750 |  |
| [7/64](https://shopmath.org/drills/fractional/7-64.md) | Fractional | 0.1094 | 2.778 | 7/64 |
| [#35](https://shopmath.org/drills/number/35.md) | Number | 0.1100 | 2.794 |  |
| [2.8 mm](https://shopmath.org/drills/metric/2-8mm.md) | Metric | 0.1102 | 2.800 |  |
| [#34](https://shopmath.org/drills/number/34.md) | Number | 0.1110 | 2.819 |  |
| [2.85 mm](https://shopmath.org/drills/metric/2-85mm.md) | Metric | 0.1122 | 2.850 |  |
| [#33](https://shopmath.org/drills/number/33.md) | Number | 0.1130 | 2.870 |  |
| [2.9 mm](https://shopmath.org/drills/metric/2-9mm.md) | Metric | 0.1142 | 2.900 |  |
| [#32](https://shopmath.org/drills/number/32.md) | Number | 0.1160 | 2.946 |  |
| [2.95 mm](https://shopmath.org/drills/metric/2-95mm.md) | Metric | 0.1161 | 2.950 |  |
| [3 mm](https://shopmath.org/drills/metric/3mm.md) | Metric | 0.1181 | 3.000 |  |
| [#31](https://shopmath.org/drills/number/31.md) | Number | 0.1200 | 3.048 |  |
| [3.1 mm](https://shopmath.org/drills/metric/3-1mm.md) | Metric | 0.1220 | 3.100 |  |
| [1/8](https://shopmath.org/drills/fractional/1-8.md) | Fractional | 0.1250 | 3.175 | 1/8 |
| [3.2 mm](https://shopmath.org/drills/metric/3-2mm.md) | Metric | 0.1260 | 3.200 |  |
| [#30](https://shopmath.org/drills/number/30.md) | Number | 0.1285 | 3.264 |  |
| [3.3 mm](https://shopmath.org/drills/metric/3-3mm.md) | Metric | 0.1299 | 3.300 |  |
| [3.4 mm](https://shopmath.org/drills/metric/3-4mm.md) | Metric | 0.1339 | 3.400 |  |
| [#29](https://shopmath.org/drills/number/29.md) | Number | 0.1360 | 3.454 |  |
| [3.5 mm](https://shopmath.org/drills/metric/3-5mm.md) | Metric | 0.1378 | 3.500 |  |
| [#28](https://shopmath.org/drills/number/28.md) | Number | 0.1405 | 3.569 |  |
| [9/64](https://shopmath.org/drills/fractional/9-64.md) | Fractional | 0.1406 | 3.572 | 9/64 |
| [3.6 mm](https://shopmath.org/drills/metric/3-6mm.md) | Metric | 0.1417 | 3.600 |  |
| [#27](https://shopmath.org/drills/number/27.md) | Number | 0.1440 | 3.658 |  |
| [3.7 mm](https://shopmath.org/drills/metric/3-7mm.md) | Metric | 0.1457 | 3.700 |  |
| [#26](https://shopmath.org/drills/number/26.md) | Number | 0.1470 | 3.734 |  |
| [#25](https://shopmath.org/drills/number/25.md) | Number | 0.1495 | 3.797 |  |
| [3.8 mm](https://shopmath.org/drills/metric/3-8mm.md) | Metric | 0.1496 | 3.800 |  |
| [#24](https://shopmath.org/drills/number/24.md) | Number | 0.1520 | 3.861 |  |
| [3.9 mm](https://shopmath.org/drills/metric/3-9mm.md) | Metric | 0.1535 | 3.900 |  |
| [#23](https://shopmath.org/drills/number/23.md) | Number | 0.1540 | 3.912 |  |
| [5/32](https://shopmath.org/drills/fractional/5-32.md) | Fractional | 0.1563 | 3.969 | 5/32 |
| [#22](https://shopmath.org/drills/number/22.md) | Number | 0.1570 | 3.988 |  |
| [4 mm](https://shopmath.org/drills/metric/4mm.md) | Metric | 0.1575 | 4.000 |  |
| [#21](https://shopmath.org/drills/number/21.md) | Number | 0.1590 | 4.039 |  |
| [#20](https://shopmath.org/drills/number/20.md) | Number | 0.1610 | 4.089 |  |
| [4.1 mm](https://shopmath.org/drills/metric/4-1mm.md) | Metric | 0.1614 | 4.100 |  |
| [4.2 mm](https://shopmath.org/drills/metric/4-2mm.md) | Metric | 0.1654 | 4.200 |  |
| [#19](https://shopmath.org/drills/number/19.md) | Number | 0.1660 | 4.216 |  |
| [4.3 mm](https://shopmath.org/drills/metric/4-3mm.md) | Metric | 0.1693 | 4.300 |  |
| [#18](https://shopmath.org/drills/number/18.md) | Number | 0.1695 | 4.305 |  |
| [11/64](https://shopmath.org/drills/fractional/11-64.md) | Fractional | 0.1719 | 4.366 | 11/64 |
| [#17](https://shopmath.org/drills/number/17.md) | Number | 0.1730 | 4.394 |  |
| [4.4 mm](https://shopmath.org/drills/metric/4-4mm.md) | Metric | 0.1732 | 4.400 |  |
| [#16](https://shopmath.org/drills/number/16.md) | Number | 0.1770 | 4.496 |  |
| [4.5 mm](https://shopmath.org/drills/metric/4-5mm.md) | Metric | 0.1772 | 4.500 |  |
| [#15](https://shopmath.org/drills/number/15.md) | Number | 0.1800 | 4.572 |  |
| [4.6 mm](https://shopmath.org/drills/metric/4-6mm.md) | Metric | 0.1811 | 4.600 |  |
| [#14](https://shopmath.org/drills/number/14.md) | Number | 0.1820 | 4.623 |  |
| [#13](https://shopmath.org/drills/number/13.md) | Number | 0.1850 | 4.699 |  |
| [4.7 mm](https://shopmath.org/drills/metric/4-7mm.md) | Metric | 0.1850 | 4.700 |  |
| [3/16](https://shopmath.org/drills/fractional/3-16.md) | Fractional | 0.1875 | 4.763 | 3/16 |
| [4.8 mm](https://shopmath.org/drills/metric/4-8mm.md) | Metric | 0.1890 | 4.800 |  |
| [#12](https://shopmath.org/drills/number/12.md) | Number | 0.1890 | 4.801 |  |
| [#11](https://shopmath.org/drills/number/11.md) | Number | 0.1910 | 4.851 |  |
| [4.9 mm](https://shopmath.org/drills/metric/4-9mm.md) | Metric | 0.1929 | 4.900 |  |
| [#10](https://shopmath.org/drills/number/10.md) | Number | 0.1935 | 4.915 |  |
| [#9](https://shopmath.org/drills/number/9.md) | Number | 0.1960 | 4.978 |  |
| [5 mm](https://shopmath.org/drills/metric/5mm.md) | Metric | 0.1968 | 5.000 |  |
| [#8](https://shopmath.org/drills/number/8.md) | Number | 0.1990 | 5.055 |  |
| [5.1 mm](https://shopmath.org/drills/metric/5-1mm.md) | Metric | 0.2008 | 5.100 |  |
| [#7](https://shopmath.org/drills/number/7.md) | Number | 0.2010 | 5.105 |  |
| [13/64](https://shopmath.org/drills/fractional/13-64.md) | Fractional | 0.2031 | 5.159 | 13/64 |
| [#6](https://shopmath.org/drills/number/6.md) | Number | 0.2040 | 5.182 |  |
| [5.2 mm](https://shopmath.org/drills/metric/5-2mm.md) | Metric | 0.2047 | 5.200 |  |
| [#5](https://shopmath.org/drills/number/5.md) | Number | 0.2055 | 5.220 |  |
| [5.3 mm](https://shopmath.org/drills/metric/5-3mm.md) | Metric | 0.2087 | 5.300 |  |
| [#4](https://shopmath.org/drills/number/4.md) | Number | 0.2090 | 5.309 |  |
| [5.4 mm](https://shopmath.org/drills/metric/5-4mm.md) | Metric | 0.2126 | 5.400 |  |
| [#3](https://shopmath.org/drills/number/3.md) | Number | 0.2130 | 5.410 |  |
| [5.5 mm](https://shopmath.org/drills/metric/5-5mm.md) | Metric | 0.2165 | 5.500 |  |
| [7/32](https://shopmath.org/drills/fractional/7-32.md) | Fractional | 0.2188 | 5.556 | 7/32 |
| [5.6 mm](https://shopmath.org/drills/metric/5-6mm.md) | Metric | 0.2205 | 5.600 |  |
| [#2](https://shopmath.org/drills/number/2.md) | Number | 0.2210 | 5.613 |  |
| [5.7 mm](https://shopmath.org/drills/metric/5-7mm.md) | Metric | 0.2244 | 5.700 |  |
| [#1](https://shopmath.org/drills/number/1.md) | Number | 0.2280 | 5.791 |  |
| [5.8 mm](https://shopmath.org/drills/metric/5-8mm.md) | Metric | 0.2283 | 5.800 |  |
| [5.9 mm](https://shopmath.org/drills/metric/5-9mm.md) | Metric | 0.2323 | 5.900 |  |
| [A](https://shopmath.org/drills/letter/a.md) | Letter | 0.2340 | 5.944 |  |
| [15/64](https://shopmath.org/drills/fractional/15-64.md) | Fractional | 0.2344 | 5.953 | 15/64 |
| [6 mm](https://shopmath.org/drills/metric/6mm.md) | Metric | 0.2362 | 6.000 |  |
| [B](https://shopmath.org/drills/letter/b.md) | Letter | 0.2380 | 6.045 |  |
| [6.1 mm](https://shopmath.org/drills/metric/6-1mm.md) | Metric | 0.2402 | 6.100 |  |
| [C](https://shopmath.org/drills/letter/c.md) | Letter | 0.2420 | 6.147 |  |
| [6.2 mm](https://shopmath.org/drills/metric/6-2mm.md) | Metric | 0.2441 | 6.200 |  |
| [D](https://shopmath.org/drills/letter/d.md) | Letter | 0.2460 | 6.248 |  |
| [6.3 mm](https://shopmath.org/drills/metric/6-3mm.md) | Metric | 0.2480 | 6.300 |  |
| [E](https://shopmath.org/drills/letter/e.md) | Letter | 0.2500 | 6.350 |  |
| [1/4](https://shopmath.org/drills/fractional/1-4.md) | Fractional | 0.2500 | 6.350 | 1/4 |
| [6.4 mm](https://shopmath.org/drills/metric/6-4mm.md) | Metric | 0.2520 | 6.400 |  |
| [6.5 mm](https://shopmath.org/drills/metric/6-5mm.md) | Metric | 0.2559 | 6.500 |  |
| [F](https://shopmath.org/drills/letter/f.md) | Letter | 0.2570 | 6.528 |  |
| [6.6 mm](https://shopmath.org/drills/metric/6-6mm.md) | Metric | 0.2598 | 6.600 |  |
| [G](https://shopmath.org/drills/letter/g.md) | Letter | 0.2610 | 6.629 |  |
| [6.7 mm](https://shopmath.org/drills/metric/6-7mm.md) | Metric | 0.2638 | 6.700 |  |
| [17/64](https://shopmath.org/drills/fractional/17-64.md) | Fractional | 0.2656 | 6.747 | 17/64 |
| [H](https://shopmath.org/drills/letter/h.md) | Letter | 0.2660 | 6.756 |  |
| [6.8 mm](https://shopmath.org/drills/metric/6-8mm.md) | Metric | 0.2677 | 6.800 |  |
| [6.9 mm](https://shopmath.org/drills/metric/6-9mm.md) | Metric | 0.2717 | 6.900 |  |
| [I](https://shopmath.org/drills/letter/i.md) | Letter | 0.2720 | 6.909 |  |
| [7 mm](https://shopmath.org/drills/metric/7mm.md) | Metric | 0.2756 | 7.000 |  |
| [J](https://shopmath.org/drills/letter/j.md) | Letter | 0.2770 | 7.036 |  |
| [7.1 mm](https://shopmath.org/drills/metric/7-1mm.md) | Metric | 0.2795 | 7.100 |  |
| [K](https://shopmath.org/drills/letter/k.md) | Letter | 0.2810 | 7.137 |  |
| [9/32](https://shopmath.org/drills/fractional/9-32.md) | Fractional | 0.2813 | 7.144 | 9/32 |
| [7.2 mm](https://shopmath.org/drills/metric/7-2mm.md) | Metric | 0.2835 | 7.200 |  |
| [7.3 mm](https://shopmath.org/drills/metric/7-3mm.md) | Metric | 0.2874 | 7.300 |  |
| [L](https://shopmath.org/drills/letter/l.md) | Letter | 0.2900 | 7.366 |  |
| [7.4 mm](https://shopmath.org/drills/metric/7-4mm.md) | Metric | 0.2913 | 7.400 |  |
| [M](https://shopmath.org/drills/letter/m.md) | Letter | 0.2950 | 7.493 |  |
| [7.5 mm](https://shopmath.org/drills/metric/7-5mm.md) | Metric | 0.2953 | 7.500 |  |
| [19/64](https://shopmath.org/drills/fractional/19-64.md) | Fractional | 0.2969 | 7.541 | 19/64 |
| [7.6 mm](https://shopmath.org/drills/metric/7-6mm.md) | Metric | 0.2992 | 7.600 |  |
| [N](https://shopmath.org/drills/letter/n.md) | Letter | 0.3020 | 7.671 |  |
| [7.7 mm](https://shopmath.org/drills/metric/7-7mm.md) | Metric | 0.3031 | 7.700 |  |
| [7.8 mm](https://shopmath.org/drills/metric/7-8mm.md) | Metric | 0.3071 | 7.800 |  |
| [7.9 mm](https://shopmath.org/drills/metric/7-9mm.md) | Metric | 0.3110 | 7.900 |  |
| [5/16](https://shopmath.org/drills/fractional/5-16.md) | Fractional | 0.3125 | 7.938 | 5/16 |
| [8 mm](https://shopmath.org/drills/metric/8mm.md) | Metric | 0.3150 | 8.000 |  |
| [O](https://shopmath.org/drills/letter/o.md) | Letter | 0.3160 | 8.026 |  |
| [8.1 mm](https://shopmath.org/drills/metric/8-1mm.md) | Metric | 0.3189 | 8.100 |  |
| [8.2 mm](https://shopmath.org/drills/metric/8-2mm.md) | Metric | 0.3228 | 8.200 |  |
| [P](https://shopmath.org/drills/letter/p.md) | Letter | 0.3230 | 8.204 |  |
| [8.3 mm](https://shopmath.org/drills/metric/8-3mm.md) | Metric | 0.3268 | 8.300 |  |
| [21/64](https://shopmath.org/drills/fractional/21-64.md) | Fractional | 0.3281 | 8.334 | 21/64 |
| [8.4 mm](https://shopmath.org/drills/metric/8-4mm.md) | Metric | 0.3307 | 8.400 |  |
| [Q](https://shopmath.org/drills/letter/q.md) | Letter | 0.3320 | 8.433 |  |
| [8.5 mm](https://shopmath.org/drills/metric/8-5mm.md) | Metric | 0.3346 | 8.500 |  |
| [8.6 mm](https://shopmath.org/drills/metric/8-6mm.md) | Metric | 0.3386 | 8.600 |  |
| [R](https://shopmath.org/drills/letter/r.md) | Letter | 0.3390 | 8.611 |  |
| [8.7 mm](https://shopmath.org/drills/metric/8-7mm.md) | Metric | 0.3425 | 8.700 |  |
| [11/32](https://shopmath.org/drills/fractional/11-32.md) | Fractional | 0.3438 | 8.731 | 11/32 |
| [8.8 mm](https://shopmath.org/drills/metric/8-8mm.md) | Metric | 0.3465 | 8.800 |  |
| [S](https://shopmath.org/drills/letter/s.md) | Letter | 0.3480 | 8.839 |  |
| [8.9 mm](https://shopmath.org/drills/metric/8-9mm.md) | Metric | 0.3504 | 8.900 |  |
| [9 mm](https://shopmath.org/drills/metric/9mm.md) | Metric | 0.3543 | 9.000 |  |
| [T](https://shopmath.org/drills/letter/t.md) | Letter | 0.3580 | 9.093 |  |
| [9.1 mm](https://shopmath.org/drills/metric/9-1mm.md) | Metric | 0.3583 | 9.100 |  |
| [23/64](https://shopmath.org/drills/fractional/23-64.md) | Fractional | 0.3594 | 9.128 | 23/64 |
| [9.2 mm](https://shopmath.org/drills/metric/9-2mm.md) | Metric | 0.3622 | 9.200 |  |
| [9.3 mm](https://shopmath.org/drills/metric/9-3mm.md) | Metric | 0.3661 | 9.300 |  |
| [U](https://shopmath.org/drills/letter/u.md) | Letter | 0.3680 | 9.347 |  |
| [9.4 mm](https://shopmath.org/drills/metric/9-4mm.md) | Metric | 0.3701 | 9.400 |  |
| [9.5 mm](https://shopmath.org/drills/metric/9-5mm.md) | Metric | 0.3740 | 9.500 |  |
| [3/8](https://shopmath.org/drills/fractional/3-8.md) | Fractional | 0.3750 | 9.525 | 3/8 |
| [V](https://shopmath.org/drills/letter/v.md) | Letter | 0.3770 | 9.576 |  |
| [9.6 mm](https://shopmath.org/drills/metric/9-6mm.md) | Metric | 0.3780 | 9.600 |  |
| [9.7 mm](https://shopmath.org/drills/metric/9-7mm.md) | Metric | 0.3819 | 9.700 |  |
| [9.8 mm](https://shopmath.org/drills/metric/9-8mm.md) | Metric | 0.3858 | 9.800 |  |
| [W](https://shopmath.org/drills/letter/w.md) | Letter | 0.3860 | 9.804 |  |
| [9.9 mm](https://shopmath.org/drills/metric/9-9mm.md) | Metric | 0.3898 | 9.900 |  |
| [25/64](https://shopmath.org/drills/fractional/25-64.md) | Fractional | 0.3906 | 9.922 | 25/64 |
| [10 mm](https://shopmath.org/drills/metric/10mm.md) | Metric | 0.3937 | 10.000 |  |
| [X](https://shopmath.org/drills/letter/x.md) | Letter | 0.3970 | 10.084 |  |
| [10.1 mm](https://shopmath.org/drills/metric/10-1mm.md) | Metric | 0.3976 | 10.100 |  |
| [10.2 mm](https://shopmath.org/drills/metric/10-2mm.md) | Metric | 0.4016 | 10.200 |  |
| [Y](https://shopmath.org/drills/letter/y.md) | Letter | 0.4040 | 10.262 |  |
| [10.3 mm](https://shopmath.org/drills/metric/10-3mm.md) | Metric | 0.4055 | 10.300 |  |
| [13/32](https://shopmath.org/drills/fractional/13-32.md) | Fractional | 0.4063 | 10.319 | 13/32 |
| [10.4 mm](https://shopmath.org/drills/metric/10-4mm.md) | Metric | 0.4094 | 10.400 |  |
| [Z](https://shopmath.org/drills/letter/z.md) | Letter | 0.4130 | 10.490 |  |
| [10.5 mm](https://shopmath.org/drills/metric/10-5mm.md) | Metric | 0.4134 | 10.500 |  |
| [10.6 mm](https://shopmath.org/drills/metric/10-6mm.md) | Metric | 0.4173 | 10.600 |  |
| [10.7 mm](https://shopmath.org/drills/metric/10-7mm.md) | Metric | 0.4213 | 10.700 |  |
| [27/64](https://shopmath.org/drills/fractional/27-64.md) | Fractional | 0.4219 | 10.716 | 27/64 |
| [10.8 mm](https://shopmath.org/drills/metric/10-8mm.md) | Metric | 0.4252 | 10.800 |  |
| [10.9 mm](https://shopmath.org/drills/metric/10-9mm.md) | Metric | 0.4291 | 10.900 |  |
| [11 mm](https://shopmath.org/drills/metric/11mm.md) | Metric | 0.4331 | 11.000 |  |
| [11.1 mm](https://shopmath.org/drills/metric/11-1mm.md) | Metric | 0.4370 | 11.100 |  |
| [7/16](https://shopmath.org/drills/fractional/7-16.md) | Fractional | 0.4375 | 11.113 | 7/16 |
| [11.2 mm](https://shopmath.org/drills/metric/11-2mm.md) | Metric | 0.4409 | 11.200 |  |
| [11.3 mm](https://shopmath.org/drills/metric/11-3mm.md) | Metric | 0.4449 | 11.300 |  |
| [11.4 mm](https://shopmath.org/drills/metric/11-4mm.md) | Metric | 0.4488 | 11.400 |  |
| [11.5 mm](https://shopmath.org/drills/metric/11-5mm.md) | Metric | 0.4528 | 11.500 |  |
| [29/64](https://shopmath.org/drills/fractional/29-64.md) | Fractional | 0.4531 | 11.509 | 29/64 |
| [11.6 mm](https://shopmath.org/drills/metric/11-6mm.md) | Metric | 0.4567 | 11.600 |  |
| [11.7 mm](https://shopmath.org/drills/metric/11-7mm.md) | Metric | 0.4606 | 11.700 |  |
| [11.8 mm](https://shopmath.org/drills/metric/11-8mm.md) | Metric | 0.4646 | 11.800 |  |
| [11.9 mm](https://shopmath.org/drills/metric/11-9mm.md) | Metric | 0.4685 | 11.900 |  |
| [15/32](https://shopmath.org/drills/fractional/15-32.md) | Fractional | 0.4688 | 11.906 | 15/32 |
| [12 mm](https://shopmath.org/drills/metric/12mm.md) | Metric | 0.4724 | 12.000 |  |
| [12.1 mm](https://shopmath.org/drills/metric/12-1mm.md) | Metric | 0.4764 | 12.100 |  |
| [12.2 mm](https://shopmath.org/drills/metric/12-2mm.md) | Metric | 0.4803 | 12.200 |  |
| [12.3 mm](https://shopmath.org/drills/metric/12-3mm.md) | Metric | 0.4843 | 12.300 |  |
| [31/64](https://shopmath.org/drills/fractional/31-64.md) | Fractional | 0.4844 | 12.303 | 31/64 |
| [12.4 mm](https://shopmath.org/drills/metric/12-4mm.md) | Metric | 0.4882 | 12.400 |  |
| [12.5 mm](https://shopmath.org/drills/metric/12-5mm.md) | Metric | 0.4921 | 12.500 |  |
| [12.6 mm](https://shopmath.org/drills/metric/12-6mm.md) | Metric | 0.4961 | 12.600 |  |
| [1/2](https://shopmath.org/drills/fractional/1-2.md) | Fractional | 0.5000 | 12.700 | 1/2 |
| [12.7 mm](https://shopmath.org/drills/metric/12-7mm.md) | Metric | 0.5000 | 12.700 |  |
| [12.8 mm](https://shopmath.org/drills/metric/12-8mm.md) | Metric | 0.5039 | 12.800 |  |
| [12.9 mm](https://shopmath.org/drills/metric/12-9mm.md) | Metric | 0.5079 | 12.900 |  |
| [13 mm](https://shopmath.org/drills/metric/13mm.md) | Metric | 0.5118 | 13.000 |  |
| [33/64](https://shopmath.org/drills/fractional/33-64.md) | Fractional | 0.5156 | 13.097 | 33/64 |
| [13.1 mm](https://shopmath.org/drills/metric/13-1mm.md) | Metric | 0.5157 | 13.100 |  |
| [13.2 mm](https://shopmath.org/drills/metric/13-2mm.md) | Metric | 0.5197 | 13.200 |  |
| [13.3 mm](https://shopmath.org/drills/metric/13-3mm.md) | Metric | 0.5236 | 13.300 |  |
| [13.4 mm](https://shopmath.org/drills/metric/13-4mm.md) | Metric | 0.5276 | 13.400 |  |
| [17/32](https://shopmath.org/drills/fractional/17-32.md) | Fractional | 0.5313 | 13.494 | 17/32 |
| [13.5 mm](https://shopmath.org/drills/metric/13-5mm.md) | Metric | 0.5315 | 13.500 |  |
| [13.6 mm](https://shopmath.org/drills/metric/13-6mm.md) | Metric | 0.5354 | 13.600 |  |
| [13.7 mm](https://shopmath.org/drills/metric/13-7mm.md) | Metric | 0.5394 | 13.700 |  |
| [13.8 mm](https://shopmath.org/drills/metric/13-8mm.md) | Metric | 0.5433 | 13.800 |  |
| [35/64](https://shopmath.org/drills/fractional/35-64.md) | Fractional | 0.5469 | 13.891 | 35/64 |
| [13.9 mm](https://shopmath.org/drills/metric/13-9mm.md) | Metric | 0.5472 | 13.900 |  |
| [14 mm](https://shopmath.org/drills/metric/14mm.md) | Metric | 0.5512 | 14.000 |  |
| [14.25 mm](https://shopmath.org/drills/metric/14-25mm.md) | Metric | 0.5610 | 14.250 |  |
| [9/16](https://shopmath.org/drills/fractional/9-16.md) | Fractional | 0.5625 | 14.287 | 9/16 |
| [14.5 mm](https://shopmath.org/drills/metric/14-5mm.md) | Metric | 0.5709 | 14.500 |  |
| [37/64](https://shopmath.org/drills/fractional/37-64.md) | Fractional | 0.5781 | 14.684 | 37/64 |
| [14.75 mm](https://shopmath.org/drills/metric/14-75mm.md) | Metric | 0.5807 | 14.750 |  |
| [15 mm](https://shopmath.org/drills/metric/15mm.md) | Metric | 0.5906 | 15.000 |  |
| [19/32](https://shopmath.org/drills/fractional/19-32.md) | Fractional | 0.5938 | 15.081 | 19/32 |
| [15.25 mm](https://shopmath.org/drills/metric/15-25mm.md) | Metric | 0.6004 | 15.250 |  |
| [39/64](https://shopmath.org/drills/fractional/39-64.md) | Fractional | 0.6094 | 15.478 | 39/64 |
| [15.5 mm](https://shopmath.org/drills/metric/15-5mm.md) | Metric | 0.6102 | 15.500 |  |
| [15.75 mm](https://shopmath.org/drills/metric/15-75mm.md) | Metric | 0.6201 | 15.750 |  |
| [5/8](https://shopmath.org/drills/fractional/5-8.md) | Fractional | 0.6250 | 15.875 | 5/8 |
| [16 mm](https://shopmath.org/drills/metric/16mm.md) | Metric | 0.6299 | 16.000 |  |
| [16.25 mm](https://shopmath.org/drills/metric/16-25mm.md) | Metric | 0.6398 | 16.250 |  |
| [41/64](https://shopmath.org/drills/fractional/41-64.md) | Fractional | 0.6406 | 16.272 | 41/64 |
| [16.5 mm](https://shopmath.org/drills/metric/16-5mm.md) | Metric | 0.6496 | 16.500 |  |
| [21/32](https://shopmath.org/drills/fractional/21-32.md) | Fractional | 0.6563 | 16.669 | 21/32 |
| [16.75 mm](https://shopmath.org/drills/metric/16-75mm.md) | Metric | 0.6594 | 16.750 |  |
| [17 mm](https://shopmath.org/drills/metric/17mm.md) | Metric | 0.6693 | 17.000 |  |
| [43/64](https://shopmath.org/drills/fractional/43-64.md) | Fractional | 0.6719 | 17.066 | 43/64 |
| [17.25 mm](https://shopmath.org/drills/metric/17-25mm.md) | Metric | 0.6791 | 17.250 |  |
| [11/16](https://shopmath.org/drills/fractional/11-16.md) | Fractional | 0.6875 | 17.462 | 11/16 |
| [17.5 mm](https://shopmath.org/drills/metric/17-5mm.md) | Metric | 0.6890 | 17.500 |  |
| [17.75 mm](https://shopmath.org/drills/metric/17-75mm.md) | Metric | 0.6988 | 17.750 |  |
| [45/64](https://shopmath.org/drills/fractional/45-64.md) | Fractional | 0.7031 | 17.859 | 45/64 |
| [18 mm](https://shopmath.org/drills/metric/18mm.md) | Metric | 0.7087 | 18.000 |  |
| [18.25 mm](https://shopmath.org/drills/metric/18-25mm.md) | Metric | 0.7185 | 18.250 |  |
| [23/32](https://shopmath.org/drills/fractional/23-32.md) | Fractional | 0.7188 | 18.256 | 23/32 |
| [18.5 mm](https://shopmath.org/drills/metric/18-5mm.md) | Metric | 0.7283 | 18.500 |  |
| [47/64](https://shopmath.org/drills/fractional/47-64.md) | Fractional | 0.7344 | 18.653 | 47/64 |
| [18.75 mm](https://shopmath.org/drills/metric/18-75mm.md) | Metric | 0.7382 | 18.750 |  |
| [19 mm](https://shopmath.org/drills/metric/19mm.md) | Metric | 0.7480 | 19.000 |  |
| [3/4](https://shopmath.org/drills/fractional/3-4.md) | Fractional | 0.7500 | 19.050 | 3/4 |
| [19.25 mm](https://shopmath.org/drills/metric/19-25mm.md) | Metric | 0.7579 | 19.250 |  |
| [49/64](https://shopmath.org/drills/fractional/49-64.md) | Fractional | 0.7656 | 19.447 | 49/64 |
| [19.5 mm](https://shopmath.org/drills/metric/19-5mm.md) | Metric | 0.7677 | 19.500 |  |
| [19.75 mm](https://shopmath.org/drills/metric/19-75mm.md) | Metric | 0.7776 | 19.750 |  |
| [25/32](https://shopmath.org/drills/fractional/25-32.md) | Fractional | 0.7813 | 19.844 | 25/32 |
| [20 mm](https://shopmath.org/drills/metric/20mm.md) | Metric | 0.7874 | 20.000 |  |
| [51/64](https://shopmath.org/drills/fractional/51-64.md) | Fractional | 0.7969 | 20.241 | 51/64 |
| [20.25 mm](https://shopmath.org/drills/metric/20-25mm.md) | Metric | 0.7972 | 20.250 |  |
| [20.5 mm](https://shopmath.org/drills/metric/20-5mm.md) | Metric | 0.8071 | 20.500 |  |
| [13/16](https://shopmath.org/drills/fractional/13-16.md) | Fractional | 0.8125 | 20.637 | 13/16 |
| [20.75 mm](https://shopmath.org/drills/metric/20-75mm.md) | Metric | 0.8169 | 20.750 |  |
| [21 mm](https://shopmath.org/drills/metric/21mm.md) | Metric | 0.8268 | 21.000 |  |
| [53/64](https://shopmath.org/drills/fractional/53-64.md) | Fractional | 0.8281 | 21.034 | 53/64 |
| [21.25 mm](https://shopmath.org/drills/metric/21-25mm.md) | Metric | 0.8366 | 21.250 |  |
| [27/32](https://shopmath.org/drills/fractional/27-32.md) | Fractional | 0.8438 | 21.431 | 27/32 |
| [21.5 mm](https://shopmath.org/drills/metric/21-5mm.md) | Metric | 0.8465 | 21.500 |  |
| [21.75 mm](https://shopmath.org/drills/metric/21-75mm.md) | Metric | 0.8563 | 21.750 |  |
| [55/64](https://shopmath.org/drills/fractional/55-64.md) | Fractional | 0.8594 | 21.828 | 55/64 |
| [22 mm](https://shopmath.org/drills/metric/22mm.md) | Metric | 0.8661 | 22.000 |  |
| [7/8](https://shopmath.org/drills/fractional/7-8.md) | Fractional | 0.8750 | 22.225 | 7/8 |
| [22.25 mm](https://shopmath.org/drills/metric/22-25mm.md) | Metric | 0.8760 | 22.250 |  |
| [22.5 mm](https://shopmath.org/drills/metric/22-5mm.md) | Metric | 0.8858 | 22.500 |  |
| [57/64](https://shopmath.org/drills/fractional/57-64.md) | Fractional | 0.8906 | 22.622 | 57/64 |
| [22.75 mm](https://shopmath.org/drills/metric/22-75mm.md) | Metric | 0.8957 | 22.750 |  |
| [23 mm](https://shopmath.org/drills/metric/23mm.md) | Metric | 0.9055 | 23.000 |  |
| [29/32](https://shopmath.org/drills/fractional/29-32.md) | Fractional | 0.9063 | 23.019 | 29/32 |
| [23.25 mm](https://shopmath.org/drills/metric/23-25mm.md) | Metric | 0.9154 | 23.250 |  |
| [59/64](https://shopmath.org/drills/fractional/59-64.md) | Fractional | 0.9219 | 23.416 | 59/64 |
| [23.5 mm](https://shopmath.org/drills/metric/23-5mm.md) | Metric | 0.9252 | 23.500 |  |
| [23.75 mm](https://shopmath.org/drills/metric/23-75mm.md) | Metric | 0.9350 | 23.750 |  |
| [15/16](https://shopmath.org/drills/fractional/15-16.md) | Fractional | 0.9375 | 23.813 | 15/16 |
| [24 mm](https://shopmath.org/drills/metric/24mm.md) | Metric | 0.9449 | 24.000 |  |
| [61/64](https://shopmath.org/drills/fractional/61-64.md) | Fractional | 0.9531 | 24.209 | 61/64 |
| [24.25 mm](https://shopmath.org/drills/metric/24-25mm.md) | Metric | 0.9547 | 24.250 |  |
| [24.5 mm](https://shopmath.org/drills/metric/24-5mm.md) | Metric | 0.9646 | 24.500 |  |
| [31/32](https://shopmath.org/drills/fractional/31-32.md) | Fractional | 0.9688 | 24.606 | 31/32 |
| [24.75 mm](https://shopmath.org/drills/metric/24-75mm.md) | Metric | 0.9744 | 24.750 |  |
| [25 mm](https://shopmath.org/drills/metric/25mm.md) | Metric | 0.9843 | 25.000 |  |
| [63/64](https://shopmath.org/drills/fractional/63-64.md) | Fractional | 0.9844 | 25.003 | 63/64 |
| [1](https://shopmath.org/drills/fractional/1.md) | Fractional | 1.0000 | 25.400 | 1 |

_Diameters are nominal. A worn or run-out drill cuts oversize._

## Sources and Method for the Drill Size Chart

### Standard drill index — number, letter, fractional, metric

- **Source**: bd_warehouse drill_sizes.csv (Apache-2.0) + Wikipedia Drill bit sizes (CC BY-SA 4.0); fractional and metric computed from ANSI B94.11M / BS 328 increment patterns
- **Method**: computed+compiled
- **Verified against**: drills: 31 checks passed across 1 harness(es)

### Assumptions

- Drill diameters are nominal. Measure the hole, not the shank, when the fit matters.
- Dataset scope: Number sizes #61-#80 are stored but tagged demandTier 'extended' — query-space-map.md Appendix A found the tail thinning in the 60s. Sizes below #80 and metric sizes above 25.0 mm excluded.

**Data last verified**: August 1, 2026

## Related pages

- Drill series: [Drill bit size reference](https://shopmath.org/drills.md)
- Tap drills by thread: [Tap drill chart](https://shopmath.org/charts/tap-drill.md)
- Threads: [Screw thread reference](https://shopmath.org/threads.md)

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*Source: [ShopMath](https://shopmath.org/charts/drill-sizes) — data verified August 1, 2026. Reference data; verify against the governing standard before manufacture.*