Metric tap-drill chart
Choose the full thread designation, including pitch. These cutting-tap recommendations belong to that exact thread, not just its major diameter.
Select a drill diameter to centre that hole on the chart while keeping its thread as the pinned base.
Coarse metric threads
| Thread & major diameter | Tap drill Open on chart ↗ |
|---|---|
M1.6 × 0.35Basic major Ø 1.6 mm · coarse | Ø 1.25 mm |
M2 × 0.4Basic major Ø 2 mm · coarse | Ø 1.6 mm |
M2.5 × 0.45Basic major Ø 2.5 mm · coarse | Ø 2.05 mm |
M3 × 0.5Basic major Ø 3 mm · coarse | Ø 2.5 mm |
M3.5 × 0.6Basic major Ø 3.5 mm · coarse | Ø 2.9 mm |
M4 × 0.7Basic major Ø 4 mm · coarse | Ø 3.3 mm |
M4.5 × 0.75Basic major Ø 4.5 mm · coarse | Ø 3.7 mm |
M5 × 0.8Basic major Ø 5 mm · coarse | Ø 4.2 mm |
M6 × 1Basic major Ø 6 mm · coarse | Ø 5 mm |
M8 × 1.25Basic major Ø 8 mm · coarse | Ø 6.8 mm |
M10 × 1.5Basic major Ø 10 mm · coarse | Ø 8.5 mm |
M12 × 1.75Basic major Ø 12 mm · coarse | Ø 10.2 mm |
M14 × 2Basic major Ø 14 mm · coarse | Ø 12 mm |
M16 × 2Basic major Ø 16 mm · coarse | Ø 14 mm |
M18 × 2.5Basic major Ø 18 mm · coarse | Ø 15.5 mm |
M20 × 2.5Basic major Ø 20 mm · coarse | Ø 17.5 mm |
M22 × 2.5Basic major Ø 22 mm · coarse | Ø 19.5 mm |
M24 × 3Basic major Ø 24 mm · coarse | Ø 21 mm |
M27 × 3Basic major Ø 27 mm · coarse | Ø 24 mm |
M30 × 3.5Basic major Ø 30 mm · coarse | Ø 26.5 mm |
M33 × 3.5Basic major Ø 33 mm · coarse | Ø 29.5 mm |
M36 × 4Basic major Ø 36 mm · coarse | Ø 32 mm |
M42 × 4.5Basic major Ø 42 mm · coarse | Ø 37.5 mm |
M45 × 4.5Basic major Ø 45 mm · coarse | Ø 40.5 mm |
M48 × 5Basic major Ø 48 mm · coarse | Ø 43 mm |
M52 × 5Basic major Ø 52 mm · coarse | Ø 47 mm |
M56 × 5.5Basic major Ø 56 mm · coarse | Ø 50.5 mm |
Fine metric threads
| Thread & major diameter | Tap drill Open on chart ↗ |
|---|---|
M4 × 0.5Basic major Ø 4 mm · fine | Ø 3.5 mm |
M5 × 0.5Basic major Ø 5 mm · fine | Ø 4.5 mm |
M6 × 0.75Basic major Ø 6 mm · fine | Ø 5.3 mm |
M8 × 1Basic major Ø 8 mm · fine | Ø 7 mm |
M10 × 1Basic major Ø 10 mm · fine | Ø 9 mm |
M10 × 1.25Basic major Ø 10 mm · fine | Ø 8.8 mm |
M12 × 1.25Basic major Ø 12 mm · fine | Ø 10.8 mm |
M12 × 1.5Basic major Ø 12 mm · fine | Ø 10.5 mm |
M14 × 1.25Basic major Ø 14 mm · fine | Ø 12.8 mm |
M14 × 1.5Basic major Ø 14 mm · fine | Ø 12.5 mm |
M16 × 1.5Basic major Ø 16 mm · fine | Ø 14.5 mm |
M18 × 1.5Basic major Ø 18 mm · fine | Ø 16.5 mm |
M20 × 1.5Basic major Ø 20 mm · fine | Ø 18.5 mm |
M22 × 1.5Basic major Ø 22 mm · fine | Ø 20.5 mm |
M24 × 2Basic major Ø 24 mm · fine | Ø 22 mm |
M25 × 1.5Basic major Ø 25 mm · fine | Ø 23.5 mm |
M32 × 1.5Basic major Ø 32 mm · fine | Ø 30.5 mm |
M40 × 1.5Basic major Ø 40 mm · fine | Ø 38.5 mm |
M50 × 1.5Basic major Ø 50 mm · fine | Ø 48.5 mm |
Recommendations vary with material, engagement and tool. These values are transcribed from the Alpha / Sterling chart, not calculated by subtracting pitch. They are not intended for forming taps. A nearby catalogue drill is a dimensional comparison, not a substitute recommendation.
Read the whole designation
In a designation such as M6 × 1, M6 identifies the 6 mm basic major diameter and 1 specifies a 1 mm pitch. A fine-pitch M6 × 0.75 is a different thread with a different tapping recommendation.
Equal basic diameters do not establish compatibility. Confirm the pitch, thread form, tolerances and mating standard. Omitted sizes or pitches are outside this selected table, not evidence that they do not exist.
Sources & scope
Data edition 1.0. Values come from the reference sources below. SizeAxis is a selected reference catalogue; it does not certify manufactured dimensions or thread compatibility.
Read the measurement definitions and full coverage