Machining and Fastener Charts
Metric thread pitch chart.
Pick a metric size and a pitch. You get the thread dimensions from the ISO basic profile: pitch diameter, minor diameter, thread depth and tensile stress area. The full coarse and fine chart is below. Runs in your browser; nothing is sent or stored.
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Result
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Answer first. The standard (coarse) pitch of M6 is 1.0 mm, M8 is 1.25 mm, M10 is 1.5 mm and M12 is 1.75 mm. Fine pitches are smaller: M8 x 1.0, M10 x 1.25, M12 x 1.5. The full chart is below.
Worked example
M10 x 1.5 (coarse): pitch diameter = 10 - 0.649519 x 1.5 = 9.026 mm; minor diameter of the internal thread = 10 - 1.082532 x 1.5 = 8.376 mm; thread depth = 0.54125 x 1.5 = 0.812 mm. The tensile stress area works out near 58 mm², matching the published bolt tables.
How it works
Coarse and fine. The coarse pitch is the commonly used default for a given diameter. Fine pitches are for applications where the height of the coarse thread would be unsuitable. A metric thread is written M8 for coarse and M8 x 1 for fine.
Basic profile. The ISO metric thread has a 60 degree angle. With H = 0.866025 P, the thread depth is 0.54125 P, the pitch diameter is D - 0.649519 P and the minor diameter is D - 1.082532 P.
Stress area. Following the ISO 898-1 method, the tensile stress area is pi/4 x ((d2 + d3)/2)², where d2 is the pitch diameter and d3 = d - 1.226869 P is the minor diameter of the external thread. Bolt strength is the stress area times the material strength of the property class.
Note. These are basic (nominal) dimensions. Real threads sit inside tolerance bands. This is a reference, not a substitute for the thread standard when you machine or inspect parts.
Metric thread pitch chart (M1 to M64)
| Size | Coarse pitch (mm) | Fine pitch (mm) | Minor dia., coarse (mm) | Stress area, coarse (mm²) |
|---|---|---|---|---|
| M1 | 0.25 | 0.2 | 0.729 | 0.5 |
| M1.2 | 0.25 | 0.2 | 0.929 | 0.7 |
| M1.4 | 0.3 | 0.2 | 1.075 | 1.0 |
| M1.6 | 0.35 | 0.2 | 1.221 | 1.3 |
| M1.8 | 0.35 | 0.2 | 1.421 | 1.7 |
| M2 | 0.4 | 0.25 | 1.567 | 2.1 |
| M2.5 | 0.45 | 0.35 | 2.013 | 3.4 |
| M3 | 0.5 | 0.35 | 2.459 | 5.0 |
| M3.5 | 0.6 | 0.35 | 2.850 | 6.8 |
| M4 | 0.7 | 0.5 | 3.242 | 8.8 |
| M5 | 0.8 | 0.5 | 4.134 | 14.2 |
| M6 | 1 | 0.75 | 4.917 | 20.1 |
| M7 | 1 | 0.75 | 5.917 | 28.9 |
| M8 | 1.25 | 1 or 0.75 | 6.647 | 36.6 |
| M10 | 1.5 | 1.25 or 1 | 8.376 | 58.0 |
| M12 | 1.75 | 1.5 or 1.25 | 10.106 | 84.3 |
| M14 | 2 | 1.5 | 11.835 | 115.4 |
| M16 | 2 | 1.5 | 13.835 | 156.7 |
| M18 | 2.5 | 2 or 1.5 | 15.294 | 192.5 |
| M20 | 2.5 | 2 or 1.5 | 17.294 | 244.8 |
| M22 | 2.5 | 2 or 1.5 | 19.294 | 303.4 |
| M24 | 3 | 2 | 20.752 | 352.5 |
| M27 | 3 | 2 | 23.752 | 459.4 |
| M30 | 3.5 | 2 | 26.211 | 560.6 |
| M33 | 3.5 | 2 | 29.211 | 693.6 |
| M36 | 4 | 3 | 31.670 | 816.7 |
| M39 | 4 | 3 | 34.670 | 975.8 |
| M42 | 4.5 | 3 | 37.129 | 1120.9 |
| M45 | 4.5 | 3 | 40.129 | 1306.0 |
| M48 | 5 | 3 | 42.587 | 1473.1 |
| M52 | 5 | 4 | 46.587 | 1757.8 |
| M56 | 5.5 | 4 | 50.046 | 2030.0 |
| M60 | 5.5 | 4 | 54.046 | 2362.0 |
| M64 | 6 | 4 | 57.505 | 2676.0 |
Sources
- ISO metric screw thread - Wikipedia (pitch table and profile formulas) (opened 2026-10-16)
- Threaded Bolts - Stress Area - Engineering ToolBox (ISO 898-1 stress area method) (opened 2026-10-16)
Pitches and the profile formulas are from the first page; the stress area method is from the second. Sizes shown are the ISO 262 selected sizes listed on that page.
FAQ
What is the thread pitch of M8?
The coarse pitch of M8 is 1.25 mm. The fine pitches are 1.0 mm and 0.75 mm.
What is the pitch of an M10 bolt?
The coarse pitch of M10 is 1.5 mm. The fine pitches are 1.25 mm and 1.0 mm.
What does M12 x 1.25 mean?
It is a 12 mm metric thread with a 1.25 mm pitch. Because the coarse pitch of M12 is 1.75 mm, the 1.25 mm pitch is a fine thread.
How do I find the pitch of a metric thread I have?
Measure the major diameter with calipers, then check a pitch gauge or count the threads over a known length. The distance between neighbouring crests in mm is the pitch.
Is this the same as a tap drill chart?
Not quite. A tap drill is close to the minor diameter of the internal thread. Use the tap drill calculator for the drill size to pick.