1-1/2-11.5 NPT vs G1-1/4: specs compared
Updated 05 September 2026.
48.26 mm
1-1/2-11.5 NPT wins on major diameter
On major diameter, 1-1/2-11.5 NPT leads: 48.26 mm versus 41.91 mm.
| Spec | 1-1/2-11.5 NPT | G1-1/4 |
|---|---|---|
| Designation | 1-1/2-11.5 NPT | G1-1/4 |
| Major diameter | 48.26 mm | 41.91 mm |
| Threads per inch / pitch | 11.5 | 11 |
| Thread form | tapered, 60 degree | parallel, 55 degree |
| Seals on | on the thread flanks with PTFE tape | flat washer or bonded seal on the face |
Questions and answers
Which has the higher major diameter, 1-1/2-11.5 NPT or G1-1/4?
On major diameter, 1-1/2-11.5 NPT leads: 48.26 mm versus 41.91 mm.
How do 1-1/2-11.5 NPT and G1-1/4 compare?
On major diameter, 1-1/2-11.5 NPT leads: 48.26 mm versus 41.91 mm.