Pipe Nominal Diameter to MM and Inches Chart
As per ASME, the word pipe is used, as distinguished from tube, to apply to tubular products of dimensions commonly used for pipeline and
piping systems.
Pipes NPS 12 (DN 300) and smaller have outside diameters numerically larger than their corresponding sizes. In contrast, the outside diameters of tubes are numerically identical to the size number for all sizes.
The manufacture of pipe NPS 1⁄8 (DN 6) to NPS 12 (DN 300), inclusive, is based on a standardised outside diameter (OD). The manufacture of pipe NPS 14 (DN 350) and larger proceeds on the basis of an OD corresponding to the nominal size.
Understand the basic
- ASME B36.10 provide welded and seamless wrought steel pipe dimensions for high or low temperatures and pressures.
- ASME B36.19 standardisation of welded and seamless wrought stainless steel pipe dimensions for high or low temperatures and pressures.
Dimensions of Welded and Seamless Wrought Steel Pipe (Pipe Nominal Bore to MM and Inches Chart)
| NPS | DN | Inches | Schedule | Millimeter | ||
| OD | Wall Thickness | OD | Wall Thickness | |||
| 1/8 | 6 | 0.405 | 0.049 | 10/10S | 10.3 | 1.24 |
| 1/8 | 6 | 0.405 | 0.068 | STD/40/40S | 10.3 | 1.73 |
| 1/8 | 6 | 0.405 | 0.095 | XS/80/80S | 10.3 | 2.41 |
| 1/4 | 8 | 0.54 | 0.065 | 10/10S | 13.7 | 1.65 |
| 1/4 | 8 | 0.54 | 0.088 | STD/40/40S | 13.7 | 2.24 |
| 1/4 | 8 | 0.54 | 0.119 | XS/80/80S | 13.7 | 3.02 |
| 3/8 | 10 | 0.675 | 0.065 | 10/10S | 17.1 | 1.65 |
| 3/8 | 10 | 0.675 | 0.091 | STD 40/40S | 17.1 | 2.31 |
| 3/8 | 10 | 0.675 | 0.126 | XS 80/80S | 17.1 | 3.2 |
| 1/2 | 15 | 0.84 | 0.065 | 5/5S | 21.3 | 1.65 |
| 1/2 | 15 | 0.84 | 0.083 | 10/10S | 21.3 | 2.11 |
| 1/2 | 15 | 0.84 | 0.109 | STD 40/40S | 21.3 | 2.77 |
| 1/2 | 15 | 0.84 | 0.147 | XS 80/80S | 21.3 | 3.73 |
| 1/2 | 15 | 0.84 | 0.188 | 160 | 21.3 | 4.78 |
| 1/2 | 15 | 0.84 | 0.294 | XX | 21.3 | 7.47 |
| 3/4 | 20 | 1.05 | 0.065 | 5/5S | 26.7 | 1.65 |
| 3/4 | 20 | 1.05 | 0.083 | 10/10S | 26.7 | 2.11 |
| 3/4 | 20 | 1.05 | 0.113 | STD/40/40S | 26.7 | 2.87 |
| 3/4 | 20 | 1.05 | 0.154 | XS/80/80S | 26.7 | 3.91 |
| 3/4 | 20 | 1.05 | 0.219 | 160 | 26.7 | 5.56 |
| 3/4 | 20 | 1.05 | 0.308 | XX | 26.7 | 7.82 |
| 1 | 25 | 1.315 | 0.065 | 5/5S | 33.4 | 1.65 |
| 1 | 25 | 1.315 | 0.109 | 10/10S | 33.4 | 2.77 |
| 1 | 25 | 1.315 | 0.133 | STD/40/40S | 33.4 | 3.38 |
| 1 | 25 | 1.315 | 0.179 | XS/80/80S | 33.4 | 4.55 |
| 1 | 25 | 1.315 | 0.25 | 160 | 33.4 | 6.35 |
| 1 | 25 | 1.315 | 0.358 | XX | 33.4 | 9.09 |
| 1-1/4 | 32 | 1.66 | 0.065 | 5/5S | 42.2 | 1.65 |
| 1-1/4 | 32 | 1.66 | 0.109 | 10/10S | 42.2 | 2.77 |
| 1-1/4 | 32 | 1.66 | 0.14 | STD/40/40S | 42.2 | 3.56 |
| 1-1/4 | 32 | 1.66 | 0.191 | XS/80/80S | 42.2 | 4.85 |
| 1-1/4 | 32 | 1.66 | 0.25 | 160 | 42.2 | 6.35 |
| 1-1/4 | 32 | 1.66 | 0.382 | XX | 42.2 | 9.7 |
| 1-1/2 | 40 | 1.9 | 0.065 | 5/5S | 48.3 | 1.65 |
| 1-1/2 | 40 | 1.9 | 0.109 | 10/10S | 48.3 | 2.77 |
| 1-1/2 | 40 | 1.9 | 0.145 | STD/40/40S | 48.3 | 3.68 |
| 1-1/2 | 40 | 1.9 | 0.2 | XS/80/80S | 48.3 | 5.08 |
| 1-1/2 | 40 | 1.9 | 0.281 | 160 | 48.3 | 7.14 |
| 1-1/2 | 40 | 1.9 | 0.4 | XX | 48.3 | 10.16 |
| 2 | 50 | 2.375 | 0.065 | 5/5S | 60.3 | 1.65 |
| 2 | 50 | 2.375 | 0.109 | 10/10S | 60.3 | 2.77 |
| 2 | 50 | 2.375 | 0.154 | STD/40/40S | 60.3 | 3.91 |
| 2 | 50 | 2.375 | 0.218 | XS/80/80S | 60.3 | 5.54 |
| 2 | 50 | 2.375 | 0.344 | 160 | 60.3 | 8.74 |
| 2 | 50 | 2.375 | 0.436 | XX | 60.3 | 11.07 |
| 2-1/2 | 65 | 2.875 | 0.083 | 5/5S | 73 | 2.11 |
| 2-1/2 | 65 | 2.875 | 0.12 | 10/10S | 73 | 3.05 |
| 2-1/2 | 65 | 2.875 | 0.203 | STD/40/40S | 73 | 5.16 |
| 2-1/2 | 65 | 2.875 | 0.276 | XS/80/80S | 73 | 7.01 |
| 2-1/2 | 65 | 2.875 | 0.375 | 160 | 73 | 9.53 |
| 2-1/2 | 65 | 2.875 | 0.552 | XX | 73 | 14.02 |
| 3 | 80 | 3.5 | 0.083 | 5/5S | 88.9 | 2.11 |
| 3 | 80 | 3.5 | 0.12 | 10/10S | 88.9 | 3.05 |
| 3 | 80 | 3.5 | 0.216 | STD/40/40S | 88.9 | 5.49 |
| 3 | 80 | 3.5 | 0.3 | XS/80/80S | 88.9 | 7.62 |
| 3 | 80 | 3.5 | 0.438 | 160 | 88.9 | 11.13 |
| 3 | 80 | 3.5 | 0.6 | XX | 88.9 | 15.24 |
| 3-1/2 | 90 | 4 | 0.083 | 5/5S | 101.6 | 2.11 |
| 3-1/2 | 90 | 4 | 0.12 | 10/10S | 101.6 | 3.05 |
| 3-1/2 | 90 | 4 | 0.226 | STD 40/40S | 101.6 | 5.74 |
| 3-1/2 | 90 | 4 | 0.318 | XS 80/80S | 101.6 | 8.08 |
| 3-1/2 | 90 | 4 | 0.636 | XX | 101.6 | 16.15 |
| 4 | 100 | 4.5 | 0.083 | 5/5S | 114.3 | 2.11 |
| 4 | 100 | 4.5 | 0.12 | 10/10S | 114.3 | 3.05 |
| 4 | 100 | 4.5 | 0.237 | STD 40/40S | 114.3 | 6.02 |
| 4 | 100 | 4.5 | 0.337 | XS 80/80S | 114.3 | 8.56 |
| 4 | 100 | 4.5 | 0.438 | 120 | 114.3 | 11.13 |
| 4 | 100 | 4.5 | 0.531 | 160 | 114.3 | 13.49 |
| 4 | 100 | 4.5 | 0.674 | XX | 114.3 | 17.12 |
| 5 | 125 | 5.563 | 0.109 | 5/5S | 141.3 | 2.77 |
| 5 | 125 | 5.563 | 0.134 | 10/10S | 141.3 | 3.4 |
| 5 | 125 | 5.563 | 0.258 | STD 40/40S | 141.3 | 6.55 |
| 5 | 125 | 5.563 | 0.375 | XS 80/80S | 141.3 | 9.53 |
| 5 | 125 | 5.563 | 0.5 | 120 | 141.3 | 12.7 |
| 5 | 125 | 5.563 | 0.625 | 160 | 141.3 | 15.88 |
| 5 | 125 | 5.563 | 0.75 | XX | 141.3 | 19.05 |
| 6 | 150 | 6.625 | 0.109 | 5/5S | 168.3 | 2.77 |
| 6 | 150 | 6.625 | 0.134 | 10/10S | 168.3 | 3.4 |
| 6 | 150 | 6.625 | 0.28 | STD 40/40S | 168.3 | 7.11 |
| 6 | 150 | 6.625 | 0.432 | XS 80/80S | 168.3 | 10.97 |
| 6 | 150 | 6.625 | 0.562 | 120 | 168.3 | 14.27 |
| 6 | 150 | 6.625 | 0.719 | 160 | 168.3 | 18.26 |
| 6 | 150 | 6.625 | 0.864 | XX | 168.3 | 21.95 |
| 8 | 200 | 8.625 | 0.109 | 5S | 219.1 | 2.77 |
| 8 | 200 | 8.625 | 0.148 | 10/10S | 219.1 | 3.76 |
| 8 | 200 | 8.625 | 0.25 | 20 | 219.1 | 6.35 |
| 8 | 200 | 8.625 | 0.277 | 30 | 219.1 | 7.04 |
| 8 | 200 | 8.625 | 0.322 | STD/40/40S | 219.1 | 8.18 |
| 8 | 200 | 8.625 | 0.406 | 60 | 219.1 | 10.31 |
| 8 | 200 | 8.625 | 0.5 | XS/80/80S | 219.1 | 12.7 |
| 8 | 200 | 8.625 | 0.594 | 100 | 219.1 | 15.09 |
| 8 | 200 | 8.625 | 0.719 | 120 | 219.1 | 18.26 |
| 8 | 200 | 8.625 | 0.812 | 140 | 219.1 | 20.62 |
| 8 | 200 | 8.625 | 0.875 | XX | 219.1 | 22.23 |
| 8 | 200 | 8.625 | 0.906 | 160 | 219.1 | 23.01 |
| 10 | 250 | 10.75 | 0.134 | 5S | 273.1 | 3.4 |
| 10 | 250 | 10.75 | 0.165 | 10S | 273.1 | 4.19 |
| 10 | 250 | 10.75 | 0.25 | 20 | 273.1 | 6.35 |
| 10 | 250 | 10.75 | 0.307 | 30 | 273.1 | 7.8 |
| 10 | 250 | 10.75 | 0.365 | STD/40/40S | 273.1 | 9.27 |
| 10 | 250 | 10.75 | 0.5 | XS/60/80S | 273.1 | 12.7 |
| 10 | 250 | 10.75 | 0.594 | 80 | 273.1 | 15.09 |
| 10 | 250 | 10.75 | 0.719 | 100 | 273.1 | 18.26 |
| 10 | 250 | 10.75 | 0.844 | 120 | 273.1 | 21.44 |
| 10 | 250 | 10.75 | 1 | 140/XX | 273.1 | 25.4 |
| 10 | 250 | 10.75 | 1.125 | 160 | 273.1 | 28.58 |
| 12 | 300 | 12.75 | 0.156 | 5S | 323.9 | 3.96 |
| 12 | 300 | 12.75 | 0.18 | 10S | 323.9 | 4.57 |
| 12 | 300 | 12.75 | 0.25 | 20 | 323.9 | 6.35 |
| 12 | 300 | 12.75 | 0.33 | 30 | 323.9 | 8.38 |
| 12 | 300 | 12.75 | 0.375 | STD/40S | 323.9 | 9.53 |
| 12 | 300 | 12.75 | 0.406 | 40 | 323.9 | 10.31 |
| 12 | 300 | 12.75 | 0.5 | XS/80S | 323.9 | 12.7 |
| 12 | 300 | 12.75 | 0.562 | 60 | 323.9 | 14.27 |
| 12 | 300 | 12.75 | 0.688 | 80 | 323.9 | 17.48 |
| 12 | 300 | 12.75 | 0.844 | 100 | 323.9 | 21.44 |
| 12 | 300 | 12.75 | 1 | 120/XX | 323.9 | 25.4 |
| 12 | 300 | 12.75 | 1.125 | 140 | 323.9 | 28.58 |
| 12 | 300 | 12.75 | 1.312 | 160 | 323.9 | 33.32 |
| 14 | 350 | 14 | 0.188 | 10S | 355.6 | 4.78 |
| 14 | 350 | 14 | 0.25 | 10 | 355.6 | 6.35 |
| 14 | 350 | 14 | 0.312 | 20 | 355.6 | 7.92 |
| 14 | 350 | 14 | 0.375 | STD/30/40S | 355.6 | 9.53 |
| 14 | 350 | 14 | 0.438 | 40 | 355.6 | 11.13 |
| 14 | 350 | 14 | 0.5 | XS/80S | 355.6 | 12.7 |
| 14 | 350 | 14 | 0.594 | 60 | 355.6 | 15.09 |
| 14 | 350 | 14 | 0.75 | 80 | 355.6 | 19.05 |
| 14 | 350 | 14 | 0.938 | 100 | 355.6 | 23.83 |
| 14 | 350 | 14 | 1.094 | 120 | 355.6 | 27.79 |
| 14 | 350 | 14 | 1.25 | 140 | 355.6 | 31.75 |
| 14 | 350 | 14 | 1.406 | 160 | 355.6 | 35.71 |
| 16 | 400 | 16 | 0.188 | 10S | 406.4 | 4.78 |
| 16 | 400 | 16 | 0.25 | 10 | 406.4 | 6.35 |
| 16 | 400 | 16 | 0.312 | 20 | 406.4 | 7.92 |
| 16 | 400 | 16 | 0.375 | STD/30/40S | 406.4 | 9.53 |
| 16 | 400 | 16 | 0.5 | XS/40/80S | 406.4 | 12.7 |
| 16 | 400 | 16 | 0.656 | 60 | 406.4 | 16.66 |
| 16 | 400 | 16 | 0.844 | 80 | 406.4 | 21.44 |
| 16 | 400 | 16 | 1.031 | 100 | 406.4 | 26.2 |
| 16 | 400 | 16 | 1.219 | 120 | 406.4 | 30.96 |
| 16 | 400 | 16 | 1.438 | 140 | 406.4 | 36.53 |
| 16 | 400 | 16 | 1.594 | 160 | 406.4 | 40.49 |
| 18 | 450 | 18 | 0.188 | 10S | 457.2 | 4.78 |
| 18 | 450 | 18 | 0.25 | 10 | 457.2 | 6.35 |
| 18 | 450 | 18 | 0.312 | 20 | 457.2 | 7.92 |
| 18 | 450 | 18 | 0.375 | STD/40S | 457.2 | 9.53 |
| 18 | 450 | 18 | 0.438 | 30 | 457.2 | 11.13 |
| 18 | 450 | 18 | 0.5 | XS/80S | 457.2 | 12.7 |
| 18 | 450 | 18 | 0.562 | 40 | 457.2 | 14.27 |
| 18 | 450 | 18 | 0.75 | 60 | 457.2 | 19.05 |
| 18 | 450 | 18 | 0.938 | 80 | 457.2 | 23.83 |
| 18 | 450 | 18 | 1.156 | 100 | 457.2 | 29.36 |
| 18 | 450 | 18 | 1.375 | 120 | 457.2 | 34.93 |
| 18 | 450 | 18 | 1.562 | 140 | 457.2 | 39.67 |
| 18 | 450 | 18 | 1.781 | 160 | 457.2 | 45.24 |
| 20 | 500 | 20 | 0.218 | 10S | 508 | 5.54 |
| 20 | 500 | 20 | 0.25 | 10 | 508 | 6.35 |
| 20 | 500 | 20 | 0.375 | STD/20/40S | 508 | 9.53 |
| 20 | 500 | 20 | 0.5 | XS/30/80S | 508 | 12.7 |
| 20 | 500 | 20 | 0.594 | 40 | 508 | 15.09 |
| 20 | 500 | 20 | 0.812 | 60 | 508 | 20.62 |
| 20 | 500 | 20 | 1.031 | 80 | 508 | 26.19 |
| 20 | 500 | 20 | 1.281 | 100 | 508 | 32.54 |
| 20 | 500 | 20 | 1.5 | 120 | 508 | 38.1 |
| 20 | 500 | 20 | 1.75 | 140 | 508 | 44.45 |
| 20 | 500 | 20 | 1.969 | 160 | 508 | 50.01 |
| 24 | 600 | 24 | 0.25 | 10/10S | 609.6 | 6.35 |
| 24 | 600 | 24 | 0.375 | STD/20/40S | 609.6 | 9.53 |
| 24 | 600 | 24 | 0.5 | XS/80S | 609.6 | 12.7 |
| 24 | 600 | 24 | 0.562 | 30 | 609.6 | 14.27 |
| 24 | 600 | 24 | 0.688 | 40 | 609.6 | 17.48 |
| 24 | 600 | 24 | 0.969 | 60 | 609.6 | 24.61 |
| 24 | 600 | 24 | 1.219 | 80 | 609.6 | 30.96 |
| 24 | 600 | 24 | 1.531 | 100 | 609.6 | 38.89 |
| 24 | 600 | 24 | 1.812 | 120 | 609.6 | 46.02 |
| 24 | 600 | 24 | 2.062 | 140 | 609.6 | 52.37 |
| 24 | 600 | 24 | 2.344 | 160 | 609.6 | 59.54 |
| 30 | 750 | 30 | 0.312 | 10 | 762 | 7.92 |
| 30 | 750 | 30 | 0.375 | STD/40S | 762 | 9.53 |
| 30 | 750 | 30 | 0.5 | XS/20/80S | 762 | 12.7 |
| 30 | 750 | 30 | 0.625 | 30 | 762 | 15.88 |
| 36 | 900 | 36 | 0.312 | 10 | 914.4 | 7.92 |
| 36 | 900 | 36 | 0.375 | STD/40S | 914.4 | 9.53 |
| 36 | 900 | 36 | 0.5 | XS/80S | 914.4 | 12.7 |
