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NPT Thread Sizes and Dimensions

Size Chart


NPT Size Outer Diameter Threads per inch Pitch of Thread
1/16" 0.3125" 27 0.03704
1/8" 0.405" 27 0.03704
1/4" 0.540" 18 0.05556
3/8" 0.675" 18 0.05556
1/2" 0.840" 14 0.07143
3/4" 1.050" 14 0.07143
1" 1.315" 11½ 0.08696
1¼" 1.660" 11½ 0.08696
1½" 1.900" 11½ 0.08696
2" 2.375" 11½ 0.08696
2½" 2.875" 8 0.12500
3" 3.500" 8 0.12500
4" 4.500" 8 0.12500
5" 5.563" 8 0.12500
6" 6.625" 8 0.12500
10" 10.750" 8 0.12500
12" 12.750" 8 0.12500

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