NPT thread, nominal size 2 — dimensions
For NPT thread, nominal size 2, threads per inch (tpi) is disputed: 11 1/2 per en.wikipedia.org, 11½ per geminivalve.com, 11½ per trimantec.com; thread pitch (mm) is disputed: 2.2087 per en.wikipedia.org, 2.20878 per geminivalve.com; major (outside) diameter (mm) is disputed: 60.3250 per en.wikipedia.org, 60.33 per geminivalve.com, 60.4 per trimantec.com; thread angle (degrees) is 60; governing standard is ASME B1.20.1, recorded from its source on 2026-08-12.
- Thread standard
- NPT our reading
- Nominal size
- 2 verified
- Threads per inch (TPI)
- 11 1/2 sources disagree
- Thread pitch (mm)
- 2.2087 sources disagree
- Major (outside) diameter (mm)
- 60.3250 sources disagree
- Thread angle (degrees)
- 60 our reading
- Governing standard
- ASME B1.20.1 our reading
Values marked our reading are our classification of what the source says — the source does not print them in those words. The quote below is the evidence for each one; judge it yourself.
What the source says
2.375 | 60.3250 |
— en.wikipedia.org, retrieved 2026-08-12
Sources disagree
More than one authority states this, and they do not state the same thing. Both are reproduced with the source each came from — deciding between them is yours, not ours.
Threads per inch (TPI)
en.wikipedia.org says threads per inch (tpi) is 11 1/2, as of 2026-08-12.
2.375 | 60.3250 |
https://en.wikipedia.org/wiki/National_pipe_thread
geminivalve.com says threads per inch (tpi) is 11½, as of 2026-08-12.
2 | 11½ | 0.08696 | 2.20878 | 2.375 | 60.33
https://www.geminivalve.com/bsp-thread-vs-npt-fitting/
trimantec.com says threads per inch (tpi) is 11½, as of 2026-08-12.
-32 (2) | 11½ | 60.4 | 2.38 | 57.9 | 2.29
https://trimantec.com/blogs/t/thread-identification-guide
Thread pitch (mm)
en.wikipedia.org says thread pitch (mm) is 2.2087, as of 2026-08-12.
2.375 | 60.3250 |
https://en.wikipedia.org/wiki/National_pipe_thread
geminivalve.com says thread pitch (mm) is 2.20878, as of 2026-08-12.
2 | 11½ | 0.08696 | 2.20878 | 2.375 | 60.33
https://www.geminivalve.com/bsp-thread-vs-npt-fitting/
Major (outside) diameter (mm)
en.wikipedia.org says major (outside) diameter (mm) is 60.3250, as of 2026-08-12.
2.375 | 60.3250 |
https://en.wikipedia.org/wiki/National_pipe_thread
geminivalve.com says major (outside) diameter (mm) is 60.33, as of 2026-08-12.
2 | 11½ | 0.08696 | 2.20878 | 2.375 | 60.33
https://www.geminivalve.com/bsp-thread-vs-npt-fitting/
trimantec.com says major (outside) diameter (mm) is 60.4, as of 2026-08-12.
-32 (2) | 11½ | 60.4 | 2.38 | 57.9 | 2.29
Sources
- en.wikipedia.orghttps://en.wikipedia.org/wiki/National_pipe_thread
- geminivalve.comhttps://www.geminivalve.com/bsp-thread-vs-npt-fitting/
- trimantec.comhttps://trimantec.com/blogs/t/thread-identification-guide