NPT Thread Chart for basic dimensions of general purpose NPT pipe threads (inch) according to ANSI/ASME B1.20.1 standard.
American National Standard Taper Pipe Thread (NPT) Chart
Note: The dimensions of the NPT Thread are given to four or five decimal places. While this implies a greater degree of precision than is ordinarily achieved, these dimensions are the basis of gage dimensions and are so expressed for the purpose of eliminating errors in computations.
Notea: Given as information for use in selecting tap drills. See Tap Drill Sizes for NPT Pipe Threads .
Noteb: Reference dimension.
- NPT Thread taper angle = 1/16 taper = 1 deg. 47 min = 0.75 in./ft .
- The angle between the sides of the thread is 60 deg.
- Thread Designation: The nominal pipe size, number of threads per inch and the thread series symbol in sequence. Ex: 3/8 - 18 NPT
- For additional dimensions, see NPT Pipe Thread Calculator.