Pipe Schedule Chart — NPS 1/8 to 24 (DN 6–600)
Welded and seamless steel pipe per ASME B36.10M / EN 10220
Every standard pipe size from NPS 1/8 (DN 6) to NPS 24 (DN 600). The outside diameter is fixed per size; the schedule number sets the wall. Click a size for its full page with every schedule — wall, inside diameter, kg/m and lb/ft.
Pipe sizes — NPS 1/8 to 24
| Size | OD mm (in) | Sch 40/STD wall (mm) | Sch 40/STD (kg/m) |
|---|---|---|---|
| NPS 1/8 (DN 6) | 10.3 (0.406") | 1.73 | 0.37 |
| NPS 1/4 (DN 8) | 13.7 (0.539") | 2.24 | 0.63 |
| NPS 3/8 (DN 10) | 17.1 (0.673") | 2.31 | 0.84 |
| NPS 1/2 (DN 15) | 21.3 (0.839") | 2.77 | 1.27 |
| NPS 3/4 (DN 20) | 26.7 (1.051") | 2.87 | 1.69 |
| NPS 1 (DN 25) | 33.4 (1.315") | 3.38 | 2.5 |
| NPS 1-1/4 (DN 32) | 42.2 (1.661") | 3.56 | 3.39 |
| NPS 1-1/2 (DN 40) | 48.3 (1.902") | 3.68 | 4.05 |
| NPS 2 (DN 50) | 60.3 (2.374") | 3.91 | 5.44 |
| NPS 2-1/2 (DN 65) | 73 (2.874") | 5.16 | 8.63 |
| NPS 3 (DN 80) | 88.9 (3.5") | 5.49 | 11.29 |
| NPS 3-1/2 (DN 90) | 101.6 (4") | 5.74 | 13.57 |
| NPS 4 (DN 100) | 114.3 (4.5") | 6.02 | 16.07 |
| NPS 5 (DN 125) | 141.3 (5.563") | 6.55 | 21.77 |
| NPS 6 (DN 150) | 168.3 (6.626") | 7.11 | 28.26 |
| NPS 8 (DN 200) | 219.1 (8.626") | 8.18 | 42.55 |
| NPS 10 (DN 250) | 273 (10.748") | 9.27 | 60.29 |
| NPS 12 (DN 300) | 323.8 (12.748") | 9.53 | 73.86 |
| NPS 14 (DN 350) | 355.6 (14") | 9.53 | 81.33 |
| NPS 16 (DN 400) | 406.4 (16") | 9.53 | 93.27 |
| NPS 18 (DN 450) | 457 (17.992") | 9.53 | 105.16 |
| NPS 20 (DN 500) | 508 (20") | 9.53 | 117.15 |
| NPS 24 (DN 600) | 610 (24.016") | 9.53 | 141.12 |
Frequently Asked Questions
What does pipe schedule mean?
Schedule is a wall-thickness series: the higher the number, the thicker the wall at the same outside diameter. OD never changes within a size, so fittings, flanges, and threads stay interchangeable — only pressure capacity and the bore change.
What is the difference between NPS and DN?
NPS is the North American inch-based name, DN the European millimeter-based one — NPS 2 = DN 50 is the same pipe. Both are nominal labels: the real OD of NPS 2 is 60.3 mm, not 50.8. The pages here list both names for every size.
How is pipe weight calculated?
kg/m = (OD − t) × t × 0.02466, with OD and wall t in millimeters — the standard plain-end mass formula from EN 10220 / ASME B36.10M at 7,850 kg/m³. Example: 2" Sch 40 → (60.3 − 3.91) × 3.91 × 0.02466 = 5.44 kg/m.
STD, XS and XXS — what are they?
The older weight-class names: Standard, Extra Strong, Double Extra Strong. STD equals Sch 40 up to NPS 10 and stays at 9.53 mm above; XS equals Sch 80 up to NPS 8 and stays at 12.7 mm above; XXS has no schedule equivalent for most sizes.
Values are entered from the governing standard’s published tables and cross-checked programmatically against its mass and section formulas before publication. Spotted an error? Write to advertising@metalabout.net — verified corrections ship within days. About