NPT Size
1" NPT
Full-size pipe thread for main lines, large valves, and process piping.
Last verified: 2026-07-10
| TPIThreads per inch (NPT is tapered at 3/4" per foot). | 11.5 |
|---|---|
| Pipe OD(in)Actual outside diameter of the thread / pipe. | 1.315 |
| Tap drillTypical tap drill for cutting the internal NPT thread. | 1-5/32" (1.156") |
| Typical use | Main lines, large valves, process piping |
Other npt pipe thread chart
Sources
- ANSI/ASME B1.20.1 — pipe threads, general purpose (NPT): TPI and pipe OD
- Typical NPT tap-drill charts (machining practice)