The formula of tap drill finding is
Major Diameter of the Thread – Pitch
for Example M5x0.75 thread the tapping drill is 5-0.75mm = 4.25mm.
| THREAD SIZE | DRILL (MM) | THREAD SIZE | DRILL (MM) | THREAD SIZE | DRILL (MM) |
|---|---|---|---|---|---|
| M1x0.25 | 0.75 | M9x0.75 | 8.3 | M18x2 | 16 |
| M1.2×0.25 | 0.95 | M9x1 | 8 | M18x2.5 | 15.5 |
| M1.4×0.3 | 1.1 | M9x1.25 | 7.8 | M20x1 | 19 |
| M1.6×0.35 | 1.25 | M10x0.5 | 9.5 | M20x1.5 | 18.5 |
| M1.8×0.35 | 1.45 | M10x0.75 | 9.3 | M20x2 | 18 |
| M2x0.4 | 1.6 | M10x1 | 9 | M20x2.5 | 17.5 |
| M2.2×0.45 | 1.75 | M10x1.25 | 8.8 | M22x1 | 21 |
| M2.5×0.45 | 2.05 | M10x1.5 | 8.5 | M22x1.5 | 20.5 |
| M2.6×0.45 | 2.15 | M11x1 | 10 | M22x2 | 20 |
| M3x0.35 | 2.65 | M11x1.25 | 9.8 | M22x2.5 | 19.5 |
| M3x0.5 | 2.5 | M11x1.5 | 9.5 | M24x1 | 23 |
| M3.5×0.35 | 3.15 | M12x0.5 | 11.5 | M24x1.5 | 22.5 |
| M3.5×0.6 | 2.9 | M12x0.75 | 11.3 | M24x2 | 22 |
| M4x0.5 | 3.5 | M12x1 | 11 | M24x3 | 21 |
| M4x0.7 | 3.3 | M12x1.25 | 10.3 | M25x1.5 | 23.5 |
| M4.5×0.5 | 4 | M12x1.5 | 10.5 | M25x2 | 23 |
| M4.5×0.75 | 3.75 | M12x1.75 | 10.3 | M27x3 | 24 |
| M5x0.5 | 4.5 | M13x1 | 12 | M30x3.5 | 26.5 |
| M5x0.75 | 4.25 | M14x1 | 13 | M33x3.5 | 29.5 |
| M5x0.8 | 4.2 | M14x1.25 | 12.8 | M36x4 | 32 |
| M6x0.5 | 5.5 | M14x1.5 | 12.5 | M39x4 | 35 |
| M6x0.75 | 5.25 | M14x2 | 12 | M42x4.5 | 37.5 |
| M6x1 | 5 | M15x1 | 14 | M45x4.5 | 40.5 |
| M7x0.5 | 6.5 | M15x1.5 | 13.5 | M48x5 | 43 |
| M7x0.75 | 6.25 | M16x1 | 15 | M52x5 | 47 |
| M7x1 | 6 | M16x1.25 | 14.8 | M56x5.5 | 50.5 |
| M8x0.5 | 7.5 | M16x1.5 | 14.5 | M60x5.5 | 54.5 |
| M8x0.75 | 7.25 | M16x2 | 14 | M64x6 | 58 |
| M8x1 | 7 | M18x1 | 17 | M68x6 | 62 |
| M8x1.25 | 6.8 | M18x1.5 | 16.5 | M72x6 | 66 |