NPT螺纹简要尺寸
| 管子公称尺寸 in | 1/16 | 1/8 | 1/4 | 3/8 | 1/2 | 3/4 | 1 | 1 ¼ | 1 ½ | 2 | 2 ½ | 3 | 3 ½ | 4 | |
| 管子外径 | in | 0.3125 | 0.405 | 0.540 | 0.675 | 0.840 | 1.050 | 1.315 | 1.660 | 1.900 | 2.375 | 2.875 | 3.500 | 4.000 | 4.500 |
| mm | 7.9 | 10.3 | 13.7 | 17.1 | 21.3 | 26.7 | 33.4 | 42.2 | 48.3 | 60.3 | 73.0 | 88.9 | 101.6 | 114.3 | |
| 每英寸牙数 | 27 | 18 | 14 | 11 ½ | 8 | ||||||||||
| 螺距：mm | 0.9408 | 1.411 | 1.814 | 2.209 | 3.175 | ||||||||||
| 旋合长度：mm | 4.064 | 4.102 | 5.786 | 6.096 | 8.128 | 8.611 | 10.160 | 10.668 | 11.074 | 17.323 | 19.456 | 20.853 | 21.438 | ||
| 旋合中径：mm | 7.142 | 9.489 | 12.487 | 15.926 | 19.772 | 25.117 | 31.462 | 40.218 | 46.287 | 58.325 | 70.159 | 86.068 | 98.776 | 111.433 | |