# Tap drill size chart

Standard cut-tap drill sizes with thread percentage. Data: https://machinistcharts.com/data/tap-drill.csv

| Thread | Series | Tap drill | Drill mm | Drill in | Thread % |
|---|---|---|---|---|---|
| M1.6 x 0.35 | metric coarse | 1.25 mm | 1.25 | 0.0492 | 77 |
| M2 x 0.4 | metric coarse | 1.6 mm | 1.6 | 0.063 | 77 |
| M2.5 x 0.45 | metric coarse | 2.05 mm | 2.05 | 0.0807 | 77 |
| M3 x 0.5 | metric coarse | 2.5 mm | 2.5 | 0.0984 | 77 |
| M3.5 x 0.6 | metric coarse | 2.9 mm | 2.9 | 0.1142 | 77 |
| M4 x 0.7 | metric coarse | 3.3 mm | 3.3 | 0.1299 | 77 |
| M5 x 0.8 | metric coarse | 4.2 mm | 4.2 | 0.1654 | 77 |
| M6 x 1 | metric coarse | 5 mm | 5.0 | 0.1969 | 77 |
| M8 x 1.25 | metric coarse | 6.8 mm | 6.8 | 0.2677 | 74 |
| M10 x 1.5 | metric coarse | 8.5 mm | 8.5 | 0.3346 | 77 |
| M12 x 1.75 | metric coarse | 10.2 mm | 10.2 | 0.4016 | 79 |
| M14 x 2 | metric coarse | 12 mm | 12.0 | 0.4724 | 77 |
| M16 x 2 | metric coarse | 14 mm | 14.0 | 0.5512 | 77 |
| M18 x 2.5 | metric coarse | 15.5 mm | 15.5 | 0.6102 | 77 |
| M20 x 2.5 | metric coarse | 17.5 mm | 17.5 | 0.689 | 77 |
| M22 x 2.5 | metric coarse | 19.5 mm | 19.5 | 0.7677 | 77 |
| M24 x 3 | metric coarse | 21 mm | 21.0 | 0.8268 | 77 |
| M27 x 3 | metric coarse | 24 mm | 24.0 | 0.9449 | 77 |
| M30 x 3.5 | metric coarse | 26.5 mm | 26.5 | 1.0433 | 77 |
| M33 x 3.5 | metric coarse | 29.5 mm | 29.5 | 1.1614 | 77 |
| M36 x 4 | metric coarse | 32 mm | 32.0 | 1.2598 | 77 |
| M39 x 4 | metric coarse | 35 mm | 35.0 | 1.378 | 77 |
| M42 x 4.5 | metric coarse | 37.5 mm | 37.5 | 1.4764 | 77 |
| M48 x 5 | metric coarse | 43 mm | 43.0 | 1.6929 | 77 |
| M3 x 0.35 | metric fine | 2.65 mm | 2.65 | 0.1043 | 77 |
| M4 x 0.5 | metric fine | 3.5 mm | 3.5 | 0.1378 | 77 |
| M5 x 0.5 | metric fine | 4.5 mm | 4.5 | 0.1772 | 77 |
| M6 x 0.75 | metric fine | 5.2 mm | 5.2 | 0.2047 | 82 |
| M8 x 1 | metric fine | 7 mm | 7.0 | 0.2756 | 77 |
| M10 x 1 | metric fine | 9 mm | 9.0 | 0.3543 | 77 |
| M10 x 1.25 | metric fine | 8.8 mm | 8.8 | 0.3465 | 74 |
| M12 x 1.25 | metric fine | 10.8 mm | 10.8 | 0.4252 | 74 |
| M12 x 1.5 | metric fine | 10.5 mm | 10.5 | 0.4134 | 77 |
| M14 x 1.5 | metric fine | 12.5 mm | 12.5 | 0.4921 | 77 |
| M16 x 1.5 | metric fine | 14.5 mm | 14.5 | 0.5709 | 77 |
| M18 x 1.5 | metric fine | 16.5 mm | 16.5 | 0.6496 | 77 |
| M20 x 1.5 | metric fine | 18.5 mm | 18.5 | 0.7283 | 77 |
| M22 x 1.5 | metric fine | 20.5 mm | 20.5 | 0.8071 | 77 |
| M24 x 2 | metric fine | 22 mm | 22.0 | 0.8661 | 77 |
| M27 x 2 | metric fine | 25 mm | 25.0 | 0.9843 | 77 |
| M30 x 2 | metric fine | 28 mm | 28.0 | 1.1024 | 77 |
| #1-64 | UNC | #53 | 1.51 | 0.0595 | 67 |
| #2-56 | UNC | #50 | 1.78 | 0.07 | 69 |
| #3-48 | UNC | #47 | 1.99 | 0.0785 | 76 |
| #4-40 | UNC | #43 | 2.26 | 0.089 | 71 |
| #5-40 | UNC | #38 | 2.58 | 0.1015 | 72 |
| #6-32 | UNC | #36 | 2.71 | 0.1065 | 78 |
| #8-32 | UNC | #29 | 3.45 | 0.136 | 69 |
| #10-24 | UNC | #25 | 3.8 | 0.1495 | 75 |
| #12-24 | UNC | #16 | 4.5 | 0.177 | 72 |
| 1/4-20 | UNC | #7 | 5.11 | 0.201 | 75 |
| 5/16-18 | UNC | F | 6.53 | 0.257 | 77 |
| 3/8-16 | UNC | 5/16 | 7.94 | 0.3125 | 77 |
| 7/16-14 | UNC | U | 9.35 | 0.368 | 75 |
| 1/2-13 | UNC | 27/64 | 10.72 | 0.4219 | 78 |
| 9/16-12 | UNC | 31/64 | 12.3 | 0.4844 | 72 |
| 5/8-11 | UNC | 17/32 | 13.5 | 0.5313 | 79 |
| 3/4-10 | UNC | 21/32 | 16.67 | 0.6563 | 72 |
| 7/8-9 | UNC | 49/64 | 19.45 | 0.7656 | 76 |
| 1-8 | UNC | 7/8 | 22.22 | 0.875 | 77 |
| #0-80 | UNF | 3/64 | 1.19 | 0.0469 | 81 |
| #1-72 | UNF | #53 | 1.51 | 0.0595 | 75 |
| #2-64 | UNF | #50 | 1.78 | 0.07 | 79 |
| #3-56 | UNF | #45 | 2.08 | 0.082 | 73 |
| #4-48 | UNF | #42 | 2.37 | 0.0935 | 68 |
| #5-44 | UNF | #37 | 2.64 | 0.104 | 71 |
| #6-40 | UNF | #33 | 2.87 | 0.113 | 77 |
| #8-36 | UNF | #29 | 3.45 | 0.136 | 78 |
| #10-32 | UNF | #21 | 4.04 | 0.159 | 76 |
| #12-28 | UNF | #14 | 4.62 | 0.182 | 73 |
| 1/4-28 | UNF | #3 | 5.41 | 0.213 | 80 |
| 5/16-24 | UNF | I | 6.91 | 0.272 | 75 |
| 3/8-24 | UNF | Q | 8.43 | 0.332 | 79 |
| 7/16-20 | UNF | 25/64 | 9.92 | 0.3906 | 72 |
| 1/2-20 | UNF | 29/64 | 11.51 | 0.4531 | 72 |
| 9/16-18 | UNF | 33/64 | 13.1 | 0.5156 | 65 |
| 5/8-18 | UNF | 37/64 | 14.68 | 0.5781 | 65 |
| 3/4-16 | UNF | 11/16 | 17.46 | 0.6875 | 77 |
| 7/8-14 | UNF | 13/16 | 20.64 | 0.8125 | 67 |
| 1-12 | UNF | 59/64 | 23.42 | 0.9219 | 72 |

## Method

Cut-tap drill sizes. Thread percent = (D - drill) / (0.01299 x P), equivalent to 76.98 x (D - drill) / P for metric; for inch threads P = 1/TPI.

Source page: https://machinistcharts.com/tap-drill/
Updated: 2026-10-05
Publisher: MachinistCharts (https://machinistcharts.com)