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Pipe Taper and Straight Thread Dimensions

*National Pipe Taper and Straight Thread Dimension

  NPT Size Threads
Per Inch
Dim "A"
(In.)
Dim "B"
(In.)
  1/16 27 .312 .261
  1/8 27 .405 .264
  1/4 18 .540 .402
  3/8 18 .675 .408
  1/2 14 .840 .534
  3/4 14 1.050 .546
  1 111/2 1.315 .683
  11/4 111/2 1.660 .707
Dim A refers to the height of the diameter, Dim B refers to the length of the threaded pipe are
 
Nominal
Thread
Size
Threads Per Inch
Major
Diameter
W
H
L
Coarse
(UNC)
Fine
(UNF)
  0 - 80 0.0600       
  1 64 72 0.0730      
  2 56 64 0.0860      
  3 48 56 0.0990      
  4 40 48 0.1221      
  5 40 44 0.1250      
  6 32 40 0.1380      
  8 32 36 0.1640      
  10 24 32 0.1900      
  12 24 28 0.2160      
  1/4 20 28 0.2500 7/16 11/64 0.750
  5/16 18 24 0.3125 1/2 7/32 0.875
  3/8 16 24 0.3750 9/16 1/4 1.000
  7/16 14 20 0.4375 5/8 19/64 1.125
  1/2 13 20 0.5000 3/4 11/32 1.250
  9/16 12 18 0.5625 13/16 3/8 1.375
  5/8 11 18 0.6250 15/16 27/64 1.500
  3/4 10 16 0.7500 11/8 1/2 1.750
  7/8 9 14 0.8750 15/16 37/64 2.000
  1 8 12 1.0000 11/2 43/64 2.250
  11/8 7 12 1.1250 111/16 3/4 2.500
  11/4 7 12 1.2500 17/8 27/32 2.750
  13/8 6 12 1.3750 21/16 29/32 3.000
  11/2 6 12 1.5000 21/4 1 3.250