3/4-14 NPT vs 4-8 NPT: specs compared
Updated 05 September 2026.
114.3 mm
4-8 NPT wins on major diameter
On major diameter, 4-8 NPT leads: 114.3 mm versus 26.67 mm.
| Spec | 3/4-14 NPT | 4-8 NPT |
|---|---|---|
| Designation | 3/4-14 NPT | 4-8 NPT |
| Major diameter | 26.67 mm | 114.3 mm |
| Threads per inch / pitch | 14 | 8 |
| Thread form | tapered, 60 degree | tapered, 60 degree |
| Seals on | on the thread flanks with PTFE tape | on the thread flanks with PTFE tape |
Questions and answers
Which has the higher major diameter, 3/4-14 NPT or 4-8 NPT?
On major diameter, 4-8 NPT leads: 114.3 mm versus 26.67 mm.
How do 3/4-14 NPT and 4-8 NPT compare?
On major diameter, 4-8 NPT leads: 114.3 mm versus 26.67 mm.