Metric Thread Chart (M1 to M64)
Metric thread chart from M1 to M64: coarse and fine pitch, d2, d3, D1, stress area and approximate tap drill. Labelled profile drawing, ISO 261 pitches.
For preliminary reference and dimensional comparison. Tolerances, pressure capacity and joint safety are not assessed. Confirm against the applicable standard before manufacture or final selection.
Dimension drawing and symbols
- d
- Nominal diameter mm
- P
- Thread pitch mm
- d2
- Basic pitch diameter mm
- d3
- Calculation root diameter mm
- D1
- Basic internal minor diameter mm
- As
- Calculated stress area mm²
On the basic profile d = D and d2 = D2 for external and internal threads. d3 is the root diameter used for the stress area, not a manufacturing limit. The profile angle is 60°.
ISO 261 first choice
Columns
Advanced
Visible rows: 74
Coarse pitch
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| Pitch | Profile diameters, mm | |||||||
|---|---|---|---|---|---|---|---|---|
| Size | Ppitchmm | Pfine pitchesmm | dnominal | d2pitch dia. | d3root dia. | D1nut minor dia. | Asstress areamm² | tap drillmm |
| M1 | 0.25 | 0.20 | 1.0 | 0.838 | 0.693 | 0.729 | 0.460 | 0.75 |
| M1.2 | 0.25 | 0.20 | 1.2 | 1.038 | 0.893 | 0.929 | 0.732 | 0.95 |
| M1.4 | 0.30 | 0.20 | 1.4 | 1.205 | 1.032 | 1.075 | 0.983 | 1.10 |
| M1.6 | 0.35 | 0.20 | 1.6 | 1.373 | 1.171 | 1.221 | 1.270 | 1.25 |
| M1.8 | 0.35 | 0.20 | 1.8 | 1.573 | 1.371 | 1.421 | 1.701 | 1.45 |
| M2 | 0.40 | 0.25 | 2.0 | 1.740 | 1.509 | 1.567 | 2.073 | 1.60 |
| M2.5 | 0.45 | 0.35 | 2.5 | 2.208 | 1.948 | 2.013 | 3.391 | 2.05 |
| M3 | 0.50 | 0.35 | 3.0 | 2.675 | 2.387 | 2.459 | 5.031 | 2.50 |
| M3.5 | 0.60 | 0.35 | 3.5 | 3.110 | 2.764 | 2.850 | 6.775 | 2.90 |
| M4 | 0.70 | 0.50 | 4.0 | 3.545 | 3.141 | 3.242 | 8.779 | 3.30 |
| M5 | 0.80 | 0.50 | 5.0 | 4.480 | 4.019 | 4.134 | 14.183 | 4.20 |
| M6 | 1.00 | 0.75 | 6.0 | 5.350 | 4.773 | 4.917 | 20.123 | 5.00 |
| M7 | 1.00 | 0.75 | 7.0 | 6.350 | 5.773 | 5.917 | 28.860 | 6.00 |
| M8 | 1.25 | 1.000.75 | 8.0 | 7.188 | 6.466 | 6.647 | 36.609 | 6.75 |
| M10 | 1.50 | 1.251.00 | 10.0 | 9.026 | 8.160 | 8.376 | 57.990 | 8.50 |
| M12 | 1.75 | 1.501.25 | 12.0 | 10.863 | 9.853 | 10.106 | 84.267 | 10.25 |
| M14 | 2.00 | 1.50 | 14.0 | 12.701 | 11.546 | 11.835 | 115.439 | 12.00 |
| M16 | 2.00 | 1.50 | 16.0 | 14.701 | 13.546 | 13.835 | 156.668 | 14.00 |
| M18 | 2.50 | 2.001.50 | 18.0 | 16.376 | 14.933 | 15.294 | 192.473 | 15.50 |
| M20 | 2.50 | 2.001.50 | 20.0 | 18.376 | 16.933 | 17.294 | 244.794 | 17.50 |
| M22 | 2.50 | 2.001.50 | 22.0 | 20.376 | 18.933 | 19.294 | 303.399 | 19.50 |
| M24 | 3.00 | 2.00 | 24.0 | 22.051 | 20.319 | 20.752 | 352.504 | 21.00 |
| M27 | 3.00 | 2.00 | 27.0 | 25.051 | 23.319 | 23.752 | 459.406 | 24.00 |
| M30 | 3.50 | 2.00 | 30.0 | 27.727 | 25.706 | 26.211 | 560.587 | 26.50 |
| M33 | 3.50 | 2.00 | 33.0 | 30.727 | 28.706 | 29.211 | 693.553 | 29.50 |
| M36 | 4.00 | 3.00 | 36.0 | 33.402 | 31.093 | 31.670 | 816.723 | 32.00 |
| M39 | 4.00 | 3.00 | 39.0 | 36.402 | 34.093 | 34.670 | 975.753 | 35.00 |
| M42 | 4.50 | 3.00 | 42.0 | 39.077 | 36.479 | 37.129 | 1120.910 | 37.50 |
| M45 | 4.50 | 3.00 | 45.0 | 42.077 | 39.479 | 40.129 | 1306.004 | 40.50 |
| M48 | 5.00 | 3.00 | 48.0 | 44.752 | 41.866 | 42.587 | 1473.149 | 43.00 |
| M52 | 5.00 | 4.00 | 52.0 | 48.752 | 45.866 | 46.587 | 1757.834 | 47.00 |
| M56 | 5.50 | 4.00 | 56.0 | 52.428 | 49.252 | 50.046 | 2030.018 | 50.50 |
| M60 | 5.50 | 4.00 | 60.0 | 56.428 | 53.252 | 54.046 | 2362.021 | 54.50 |
| M64 | 6.00 | 4.00 | 64.0 | 60.103 | 56.639 | 57.505 | 2675.973 | 58.00 |
Fine pitches
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| Profile diameters, mm | |||||||
|---|---|---|---|---|---|---|---|
| Size | Ppitchmm | dnominal | d2pitch dia. | d3root dia. | D1nut minor dia. | Asstress areamm² | tap drillmm |
| M1 | 0.20 | 1.0 | 0.870 | 0.755 | 0.783 | 0.518 | 0.80 |
| M1.2 | 0.20 | 1.2 | 1.070 | 0.955 | 0.983 | 0.805 | 1.00 |
| M1.4 | 0.20 | 1.4 | 1.270 | 1.155 | 1.183 | 1.154 | 1.20 |
| M1.6 | 0.20 | 1.6 | 1.470 | 1.355 | 1.383 | 1.567 | 1.40 |
| M1.8 | 0.20 | 1.8 | 1.670 | 1.555 | 1.583 | 2.042 | 1.60 |
| M2 | 0.25 | 2.0 | 1.838 | 1.693 | 1.729 | 2.448 | 1.75 |
| M2.5 | 0.35 | 2.5 | 2.273 | 2.071 | 2.121 | 3.704 | 2.15 |
| M3 | 0.35 | 3.0 | 2.773 | 2.571 | 2.621 | 5.606 | 2.65 |
| M3.5 | 0.35 | 3.5 | 3.273 | 3.071 | 3.121 | 7.901 | 3.15 |
| M4 | 0.50 | 4.0 | 3.675 | 3.387 | 3.459 | 9.792 | 3.50 |
| M5 | 0.50 | 5.0 | 4.675 | 4.387 | 4.459 | 16.124 | 4.50 |
| M6 | 0.75 | 6.0 | 5.513 | 5.080 | 5.188 | 22.031 | 5.25 |
| M7 | 0.75 | 7.0 | 6.513 | 6.080 | 6.188 | 31.136 | 6.25 |
| M8 | 1.00 | 8.0 | 7.350 | 6.773 | 6.917 | 39.167 | 7.00 |
| M8 | 0.75 | 8.0 | 7.513 | 7.080 | 7.188 | 41.812 | 7.25 |
| M10 | 1.25 | 10.0 | 9.188 | 8.466 | 8.647 | 61.199 | 8.75 |
| M10 | 1.00 | 10.0 | 9.350 | 8.773 | 8.917 | 64.494 | 9.00 |
| M12 | 1.50 | 12.0 | 11.026 | 10.160 | 10.376 | 88.126 | 10.50 |
| M12 | 1.25 | 12.0 | 11.188 | 10.466 | 10.647 | 92.072 | 10.75 |
| M14 | 1.50 | 14.0 | 13.026 | 12.160 | 12.376 | 124.546 | 12.50 |
| M16 | 1.50 | 16.0 | 15.026 | 14.160 | 14.376 | 167.248 | 14.50 |
| M18 | 2.00 | 18.0 | 16.701 | 15.546 | 15.835 | 204.181 | 16.00 |
| M18 | 1.50 | 18.0 | 17.026 | 16.160 | 16.376 | 216.234 | 16.50 |
| M20 | 2.00 | 20.0 | 18.701 | 17.546 | 17.835 | 257.976 | 18.00 |
| M20 | 1.50 | 20.0 | 19.026 | 18.160 | 18.376 | 271.503 | 18.50 |
| M22 | 2.00 | 22.0 | 20.701 | 19.546 | 19.835 | 318.055 | 20.00 |
| M22 | 1.50 | 22.0 | 21.026 | 20.160 | 20.376 | 333.056 | 20.50 |
| M24 | 2.00 | 24.0 | 22.701 | 21.546 | 21.835 | 384.416 | 22.00 |
| M27 | 2.00 | 27.0 | 25.701 | 24.546 | 24.835 | 495.740 | 25.00 |
| M30 | 2.00 | 30.0 | 28.701 | 27.546 | 27.835 | 621.201 | 28.00 |
| M33 | 2.00 | 33.0 | 31.701 | 30.546 | 30.835 | 760.799 | 31.00 |
| M36 | 3.00 | 36.0 | 34.051 | 32.319 | 32.752 | 864.937 | 33.00 |
| M39 | 3.00 | 39.0 | 37.051 | 35.319 | 35.752 | 1028.388 | 36.00 |
| M42 | 3.00 | 42.0 | 40.051 | 38.319 | 38.752 | 1205.976 | 39.00 |
| M45 | 3.00 | 45.0 | 43.051 | 41.319 | 41.752 | 1397.702 | 42.00 |
| M48 | 3.00 | 48.0 | 46.051 | 44.319 | 44.752 | 1603.565 | 45.00 |
| M52 | 4.00 | 52.0 | 49.402 | 47.093 | 47.670 | 1828.246 | 48.00 |
| M56 | 4.00 | 56.0 | 53.402 | 51.093 | 51.670 | 2143.958 | 52.00 |
| M60 | 4.00 | 60.0 | 57.402 | 55.093 | 55.670 | 2484.804 | 56.00 |
| M64 | 4.00 | 64.0 | 61.402 | 59.093 | 59.670 | 2850.782 | 60.00 |
Quick answers
- M6: coarse pitch 1 mm, fine pitch 0.75 mm, root diameter d3 4.773 mm, approximate tap drill 5 mm. View in table
- M8: coarse pitch 1.25 mm, fine pitch 1 and 0.75 mm, root diameter d3 6.466 mm, approximate tap drill 6.75 mm. View in table
- M10: coarse pitch 1.5 mm, fine pitch 1.25 and 1 mm, root diameter d3 8.16 mm, approximate tap drill 8.5 mm. View in table
- M12: coarse pitch 1.75 mm, fine pitch 1.5 and 1.25 mm, root diameter d3 9.853 mm, approximate tap drill 10.25 mm. View in table
- M16: coarse pitch 2 mm, fine pitch 1.5 mm, root diameter d3 13.546 mm, approximate tap drill 14 mm. View in table
- M20: coarse pitch 2.5 mm, fine pitch 2 and 1.5 mm, root diameter d3 16.933 mm, approximate tap drill 17.5 mm. View in table
- M24: coarse pitch 3 mm, fine pitch 2 mm, root diameter d3 20.319 mm, approximate tap drill 21 mm. View in table
Conditions and notes
Pitch selection referenced to ISO 261:1998. Geometry describes the basic profile without manufacturing tolerances.
- Each row uses its own pitch. d2 = d − 0.649519P, d3 = d − 1.226869P, D1 = d − 1.082532P and As = π/4 × ((d2 + d3)/2)².
- d3 is the calculation root diameter for stress area. Actual manufacturing limits, thread tolerances and rounded root profiles are excluded. Approximate drill d − P does not replace tool selection.
- Only common fine pitches appearing in both consulted charts are shown. This is not the complete ISO 261 pitch list.
- Coarse pitch and fine pitches are given in separate tables. Fine pitch diameters and areas are calculated with their own pitch.
- The first choice mark shows the diameters in the first preference column of ISO 261. Second choice diameters are also listed.
- CSV download is unavailable because the sources do not establish permission for reuse.
Common coarse and fine pitches from M1 to M64, basic profile diameters, calculated tensile stress area and approximate tap drill.
Sources
This table is for preliminary reference. Check the applicable standard and product conditions before use.
- Source 1. Undated numerical table. The referenced edition is stated in the conditions.. Accessed: 2026-10-16
- Source 2. Undated numerical table. The referenced edition is stated in the conditions.. Accessed: 2026-10-16
- Source 3. Version accessed. Accessed: 2026-10-16
- Source 4. Undated numerical table. The referenced edition is stated in the conditions.. Accessed: 2026-10-16
Data version: 2026-10-16