US Standard Taper Pipe Thread NPT

Note: The information contained here is for referance only of common standards and and may not accurately reflect actual product dimensions.

Please check the product details or ask if any dimension is critical

US Standard Taper Pipe Thread NPT

Pipe Size
(inches)
Threads per Inch
TPI – pitch
Approximate Length of Thread(inches) Approximate Number of Threads to be Cut Approximate Total thread Makeup, Hand and Wrench(inches) Nominal Outside Pipe Diameter
OD
(inches)
Tap Drill
(inches)
1/16″ 27 0.313
1/8″ 27 3/8 10 1/4 0.405 R
1/4″ 18 5/8 11 3/8 0.540 7/16
3/8″ 18 5/8 11 3/8 0.675 37/64
1/2″ 14 3/4 10 7/16 0.840 23/32
3/4″ 14 3/4 10 1/2 1.050 59/64
1″ 11-1/2 7/8 10 9/16 1.315 1-5/32
1-1/4″ 11-1/2 1 11 9/16 1.660 1-1/2
1-1/2″ 11-1/2 1 11 9/16 1.900 1-47/64
2″ 11-1/2 1 11 5/8 2.375 2-7/32
2-1/2″ 8 1 1/2 12 7/8 2.875 2-5/8
3″ 8 1 1/2 12 1 3.500 3-1/4
3-1/2″ 8 1 5/8 13 1 1/16 4.000 3-3/4
4″ 8 1 5/8 13 1 1/16 4.500 4-1/4
4 1/2″ 8 5.000 4-3/4
5″ 8 1 3/4 14 1 3/16 5.563 5-9/32
6″ 8 1 3/4 14 1 3/16 6.625 6-11/32
8″ 8 1 7/8 15 1 5/16 8.625
10″ 8 2 16 1 1/2 10.750
12″ 8 2 1/8 17 1 5/8 12.750
14″ 8 14.000
16″ 8 16.000