NPT Size Guide
NPT - American Standard Pipe Thread/Taper Guide:
NPT is not a measured size, but rather an industry call out size.
The NPT call out designation is not the true thread diameter inside or out.
|
PROBE THREAD SIZE |
ACTUAL OUTSIDE DIAMETER |
| 1/8" NPT | 0.405" (Approx. 13/32") |
| 1/4" NPT | 0.540" (Approx. 1/2") |
| 3/8" NPT | 0.675" (Approx. 5/8") |
| 1/2" NPT | 0.840" (Approx. 7/8") |