DN - NPS Conversion
& Pipe Schedule Table
DN to NPS conversion and pipe wall thickness values per ASME B36.10 standard.
Search & Convert DN / NPS
DN - NPS - OD & Schedule Table
| DN | NPS | OD (mm) | SCH 5 | SCH 10 | SCH 20 | SCH 30 | SCH 40 | SCH 60 | SCH 80 | SCH 100 | SCH 120 | SCH 140 | SCH 160 | STD | XS | XXS |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 15 | 1/2" | 21.3 | 1.65 | 2.11 | - | - | 2.77 | - | 3.73 | - | - | - | 4.78 | 2.77 | 3.73 | 7.47 |
| 20 | 3/4" | 26.7 | 1.65 | 2.11 | - | - | 2.87 | - | 3.91 | - | - | - | 5.56 | 2.87 | 3.91 | 7.82 |
| 25 | 1" | 33.4 | 1.65 | 2.77 | - | - | 3.38 | - | 4.55 | - | - | - | 6.35 | 3.38 | 4.55 | 9.09 |
| 32 | 1-1/4" | 42.2 | 1.65 | 2.77 | - | - | 3.56 | - | 4.85 | - | - | - | 6.35 | 3.56 | 4.85 | 9.70 |
| 40 | 1-1/2" | 48.3 | 1.65 | 2.77 | - | - | 3.68 | - | 5.08 | - | - | - | 7.14 | 3.68 | 5.08 | 10.15 |
| 50 | 2" | 60.3 | 1.65 | 2.77 | - | - | 3.91 | - | 5.54 | - | - | - | 8.74 | 3.91 | 5.54 | 11.07 |
| 65 | 2-1/2" | 73 | 2.11 | 3.05 | - | - | 5.16 | - | 7.01 | - | - | - | 9.53 | 5.16 | 7.01 | 14.02 |
| 80 | 3" | 88.9 | 2.11 | 3.05 | - | - | 5.49 | - | 7.62 | - | - | - | 11.13 | 5.49 | 7.62 | 15.24 |
| 100 | 4" | 114.3 | 2.77 | 3.05 | 3.96 | 4.78 | 6.02 | 7.14 | 8.56 | 11.13 | 13.49 | 15.88 | 17.12 | 6.02 | 8.56 | 17.12 |
| 125 | 5" | 141.3 | 2.77 | 3.40 | 5.56 | 6.55 | 6.55 | 9.53 | 9.53 | 12.70 | 15.88 | 18.26 | 19.05 | 6.55 | 9.53 | 19.05 |
| 150 | 6" | 168.3 | 2.77 | 3.40 | 5.56 | 6.35 | 7.11 | 10.97 | 10.97 | 14.27 | 18.26 | 21.95 | 21.95 | 7.11 | 10.97 | 21.95 |
| 200 | 8" | 219.1 | 2.77 | 3.76 | 6.35 | 7.04 | 8.18 | 10.31 | 12.70 | 15.09 | 18.26 | 20.62 | 23.01 | 8.18 | 12.70 | 22.23 |
| 250 | 10" | 273 | 3.40 | 4.19 | 6.35 | 7.80 | 9.27 | 12.70 | 12.70 | 18.26 | 21.44 | 25.40 | 28.58 | 9.27 | 12.70 | 28.58 |
| 300 | 12" | 323.8 | 3.96 | 4.57 | 6.35 | 8.38 | 9.53 | 12.70 | 12.70 | 21.44 | 25.40 | 28.58 | 33.32 | 9.53 | 12.70 | 33.32 |
| 350 | 14" | 355.6 | 3.96 | 4.78 | 7.92 | 9.53 | 11.13 | 15.09 | 19.05 | 23.83 | 27.79 | 31.75 | 35.71 | 9.53 | 12.70 | - |
| 400 | 16" | 406.4 | 4.19 | 4.78 | 7.92 | 9.53 | 12.70 | 16.66 | 21.44 | 26.19 | 30.96 | 36.53 | 40.49 | 9.53 | 12.70 | - |
| 450 | 18" | 457.2 | 4.19 | 4.78 | 7.92 | 11.13 | 14.27 | 19.05 | 23.83 | 29.36 | 34.93 | 39.67 | 45.24 | 9.53 | 12.70 | - |
| 500 | 20" | 508 | 4.78 | 5.54 | 9.53 | 12.70 | 15.09 | 20.62 | 26.19 | 32.54 | 38.10 | 44.45 | 50.01 | 9.53 | 12.70 | - |
| 600 | 24" | 609.6 | 5.54 | 6.35 | 9.53 | 14.27 | 17.48 | 24.61 | 30.96 | 38.89 | 46.02 | 52.37 | 59.54 | 9.53 | 12.70 | - |
* All values are in mm. Source: ASME B36.10M. Click a row to select it.
What are DN, NPS, and Schedule?
Nominal Diameter (Diametre Nominal)
DN is the metric designation used to describe pipe size. Expressed in millimeters, it does not directly represent the actual inner or outer diameter; it is an industrial reference number defined per ISO 6708.
Nominal Pipe Size
NPS is the imperial pipe sizing designation used in North America. Expressed in inches. For NPS 14 and above, NPS directly equals the OD in inches. For smaller sizes, it is a historical reference number.
Pipe Schedule
The schedule number defines the pipe wall thickness. Different schedule values for the same nominal size provide different wall thicknesses and pressure ratings. Per ASME B36.10, values from SCH 5 to SCH 160 are defined. STD, XS, and XXS are special designations.
Important Notes
- 1.STD (Standard) generally equals SCH 40 (up to DN 250). For larger sizes, STD wall thickness is fixed at 9.53 mm.
- 2.XS (Extra Strong) generally equals SCH 80 (up to DN 200). For larger sizes, XS wall thickness is fixed at 12.70 mm.
- 3.XXS (Double Extra Strong) is the heaviest standard pipe. XXS is not defined for DN 350 and above.
- 4.Outer diameter (OD) is constant for all schedules. As schedule increases, inner diameter decreases and pressure rating increases.
Pipe Weight Formula
Where W = Weight (kg/m), OD = Outer Diameter (mm), WT = Wall Thickness (mm)
Example Calculation:
DN100, SCH 40 pipe: OD = 114.3 mm, WT = 6.02 mm
W = (114.3 - 6.02) x 6.02 x 0.02466 = 16.07 kg/m