Steel Pipe Sizes Chart
| NPS | DN | Outside Diameter | Outside Diameter (Metric) |
|---|---|---|---|
| NPS 2 | 50 | 2.375 in | 60.33 mm |
| NPS 3 | 80 | 3.5 in | 88.9 mm |
| NPS 4 | 100 | 4.5 in | 114.3 mm |
| NPS 6 | 150 | 6.625 in | 168.28 mm |
| NPS 8 | 200 | 8.625 in | 219.07 mm |
| NPS 10 | 250 | 10.75 in | 273.05 mm |
| NPS 12 | 300 | 12.75 in | 323.85 mm |
Steel Pipe Size Reference
Nominal Pipe Size (NPS) identifies standard pipe sizes used for steel pipe. NPS does not directly equal the measured outside diameter. Each NPS has a standardized outside diameter, while wall thickness varies by pipe schedule.
Use the NPS links above to see available Schedule 40 and Schedule 80 dimensions, including outside diameter, wall thickness, inside diameter, and weight.
Reference standard: ASME B36.10-2022.
Related Pipe References
FAQ
What does NPS mean?
NPS means Nominal Pipe Size. It is a standardized designation used to identify pipe size and is not always equal to the actual outside diameter.
Does pipe schedule change the outside diameter?
For a given NPS, the standard outside diameter remains the same across schedules. Schedule changes primarily affect wall thickness, inside diameter, and weight.
What standard does this pipe size reference use?
The steel pipe dimensions shown here reference ASME B36.10-2022.