Popular sizes:
| Thread | Coarse pitch | Fine pitch |
|---|---|---|
| М2 | 0.40 mm | — |
| М2.5 | 0.45 mm | — |
| М3 | 0.50 mm | 0.35 mm |
| М3.5 | 0.60 mm | — |
| М4 | 0.70 mm | 0.50 mm |
| М5 | 0.80 mm | 0.50 mm |
| М6 | 1.00 mm | 0.75 mm |
| М7 | 1.00 mm | — |
| М8 | 1.25 mm | 1.00 mm |
| М10 | 1.50 mm | 1.25 mm |
| М12 | 1.75 mm | 1.50 mm |
| М14 | 2.00 mm | 1.50 mm |
| М16 | 2.00 mm | 1.50 mm |
| М18 | 2.50 mm | 1.50 mm |
| М20 | 2.50 mm | 1.50 mm |
| М22 | 2.50 mm | 1.50 mm |
| М24 | 3.00 mm | 2.00 mm |
| М27 | 3.00 mm | 2.00 mm |
| М30 | 3.50 mm | 2.00 mm |
| М33 | 3.50 mm | 2.00 mm |
| М36 | 4.00 mm | 3.00 mm |
| М39 | 4.00 mm | 3.00 mm |
| М42 | 4.50 mm | 3.00 mm |
| М45 | 4.50 mm | 3.00 mm |
| М48 | 5.00 mm | 3.00 mm |
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Popular sizes:
| Thread | TPI | Pitch (inch) | Pitch (mm) |
|---|---|---|---|
| #2-56 UNC | 56 | 0.0179″ | 0.45 mm |
| #2-64 UNF | 64 | 0.0156″ | 0.40 mm |
| #3-48 UNC | 48 | 0.0208″ | 0.53 mm |
| #3-56 UNF | 56 | 0.0179″ | 0.45 mm |
| #4-40 UNC | 40 | 0.0250″ | 0.64 mm |
| #4-48 UNF | 48 | 0.0208″ | 0.53 mm |
| #5-40 UNC | 40 | 0.0250″ | 0.64 mm |
| #5-44 UNF | 44 | 0.0227″ | 0.58 mm |
| #6-32 UNC | 32 | 0.0313″ | 0.79 mm |
| #6-40 UNF | 40 | 0.0250″ | 0.64 mm |
| #8-32 UNC | 32 | 0.0313″ | 0.79 mm |
| #8-36 UNF | 36 | 0.0278″ | 0.71 mm |
| #10-24 UNC | 24 | 0.0417″ | 1.06 mm |
| #10-32 UNF | 32 | 0.0313″ | 0.79 mm |
| #12-24 UNC | 24 | 0.0417″ | 1.06 mm |
| #12-28 UNF | 28 | 0.0357″ | 0.91 mm |
| 1/4″-20 UNC | 20 | 0.0500″ | 1.27 mm |
| 1/4″-28 UNF | 28 | 0.0357″ | 0.91 mm |
| 5/16″-18 UNC | 18 | 0.0556″ | 1.41 mm |
| 5/16″-24 UNF | 24 | 0.0417″ | 1.06 mm |
| 3/8″-16 UNC | 16 | 0.0625″ | 1.59 mm |
| 3/8″-24 UNF | 24 | 0.0417″ | 1.06 mm |
| 7/16″-14 UNC | 14 | 0.0714″ | 1.81 mm |
| 7/16″-20 UNF | 20 | 0.0500″ | 1.27 mm |
| 1/2″-13 UNC | 13 | 0.0769″ | 1.95 mm |
| 1/2″-20 UNF | 20 | 0.0500″ | 1.27 mm |
| 9/16″-12 UNC | 12 | 0.0833″ | 2.12 mm |
| 9/16″-18 UNF | 18 | 0.0556″ | 1.41 mm |
| 5/8″-11 UNC | 11 | 0.0909″ | 2.31 mm |
| 5/8″-18 UNF | 18 | 0.0556″ | 1.41 mm |
| 3/4″-10 UNC | 10 | 0.1000″ | 2.54 mm |
| 3/4″-16 UNF | 16 | 0.0625″ | 1.59 mm |
| 7/8″-9 UNC | 9 | 0.1111″ | 2.82 mm |
| 7/8″-14 UNF | 14 | 0.0714″ | 1.81 mm |
| 1″-8 UNC | 8 | 0.1250″ | 3.18 mm |
| 1″-12 UNF | 12 | 0.0833″ | 2.12 mm |
| 1 1/4″-7 UNC | 7 | 0.1429″ | 3.63 mm |
| 1 1/2″-6 UNC | 6 | 0.1667″ | 4.23 mm |
More standards, diameters and pitches in the mobile app
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Popular sizes:
| Thread | Type | TPI | Pitch (mm) |
|---|---|---|---|
| G 1/16 | BSPP | 28 | 0.907 mm |
| G 1/8 | BSPP | 28 | 0.907 mm |
| G 1/4 | BSPP | 19 | 1.337 mm |
| G 3/8 | BSPP | 19 | 1.337 mm |
| G 1/2 | BSPP | 14 | 1.814 mm |
| G 3/4 | BSPP | 14 | 1.814 mm |
| G 1 | BSPP | 11 | 2.309 mm |
| G 1 1/4 | BSPP | 11 | 2.309 mm |
| G 1 1/2 | BSPP | 11 | 2.309 mm |
| G 2 | BSPP | 11 | 2.309 mm |
| NPT 1/8 | NPT | 27 | 0.941 mm |
| NPT 1/4 | NPT | 18 | 1.411 mm |
| NPT 3/8 | NPT | 18 | 1.411 mm |
| NPT 1/2 | NPT | 14 | 1.814 mm |
| NPT 3/4 | NPT | 14 | 1.814 mm |
| NPT 1 | NPT | 11.5 | 2.209 mm |
| NPT 1 1/4 | NPT | 11.5 | 2.209 mm |
| NPT 1 1/2 | NPT | 11.5 | 2.209 mm |
| NPT 2 | NPT | 11.5 | 2.209 mm |
More standards, diameters and pitches in the mobile app
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See also
Thread pitch is the distance between adjacent thread crests, measured in mm (metric) or as threads per inch (TPI) for inch standards. Coarse pitch is used for general-purpose fasteners; fine pitch provides more thread engagement per unit length and is preferred where vibration resistance or fine adjustment is needed.
Tip: To convert TPI to pitch in mm: pitch (mm) = 25.4 ÷ TPI. Example: 20 TPI → 25.4 ÷ 20 = 1.27 mm.