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Pipe Schedule Chart (ANSI/ASME B36.10)

Standard dimensions and weights for steel pipes. Use the search bar to find specific NPS sizes.

NPS (inch) OD (mm) OD (inch) Sch 40 Wall (mm) Sch 40 Wt (kg/m) Sch 80 Wall (mm) Sch 80 Wt (kg/m)
1/8" 10.3 0.405 1.73 0.37 2.41 0.47
1/4" 13.7 0.540 2.24 0.63 3.02 0.80
1/2" 21.3 0.840 2.77 1.27 3.73 1.62
3/4" 26.7 1.050 2.87 1.69 3.91 2.20
1" 33.4 1.315 3.38 2.50 4.55 3.24
1-1/2" 48.3 1.900 3.68 4.05 5.08 5.41
2" 60.3 2.375 3.91 5.44 5.54 7.48
3" 88.9 3.500 5.49 11.29 7.62 15.27
4" 114.3 4.500 6.02 16.07 8.56 22.32
6" 168.3 6.625 7.11 28.26 10.97 42.56
8" 219.1 8.625 8.18 42.55 12.70 64.64
10" 273.1 10.750 9.27 60.31 15.09 95.97
12" 323.9 12.750 10.31 79.73 17.48 132.08

The Comprehensive Guide to ANSI/ASME B36.10 Pipe Schedules

In the world of industrial piping, precision is paramount. A Pipe Schedule Chart is the foundational reference used by engineers, pipefitters, and procurement specialists to determine the physical dimensions and weight of carbon and alloy steel pipes. Standardized by ASME B36.10M, these schedules ensure that components from different manufacturers are compatible and meet the required safety margins for pressure and temperature.

Understanding Nominal Pipe Size (NPS) vs. Outer Diameter (OD)

One of the most common points of confusion in piping design is the relationship between the Nominal Pipe Size (NPS) and the actual Outer Diameter (OD).

  • For NPS 1/8 to NPS 12: The OD is larger than the nominal size. For example, a 2-inch pipe actually has an OD of 2.375 inches.
  • For NPS 14 and larger: The OD is exactly equal to the nominal size. A 14-inch pipe has a 14-inch OD.

What Does "Pipe Schedule" Actually Mean?

The "Schedule" number (abbreviated as Sch. or Sch) relates to the wall thickness of the pipe. As the schedule number increases, the wall thickness becomes greater, while the Outer Diameter remains constant. This means that a higher schedule pipe will have a smaller Inner Diameter (ID) and a higher weight per linear foot or meter.

Key Differences Between Schedule 40 and Schedule 80

While many schedules exist (5, 10, 20, 30, 40, 60, 80, 100, 120, 140, 160, plus XXS and STD), Schedules 40 and 80 are the most prevalent:

  • Schedule 40: Often referred to as "Standard" weight for sizes up to NPS 10. It is widely used in low-to-medium pressure applications like water lines and HVAC systems.
  • Schedule 80: Often referred to as "Extra Strong" (XS) for sizes up to NPS 8. It features a thicker wall, making it suitable for high-pressure chemical processing, heavy-duty industrial infrastructure, and applications requiring extra structural rigidity.

Material Standards: ASME B36.10M vs. B36.19M

It is important to note that ASME B36.10M covers the dimensions of welded and seamless wrought steel pipe (carbon steel). For stainless steel pipe, engineers refer to ASME B36.19M, which includes schedule numbers followed by an "S" suffix (e.g., Sch 10S, Sch 40S).

* Weights provided in this chart are theoretical and based on the density of Carbon Steel (approximately 7.85 g/cm³ or 490 lb/ft³). Actual weights may vary based on manufacturing tolerances defined in ASTM standards.

Related Tools

Pipe Weight Calc → Pipe Volume Calc → Sch 40 Dimensions → Sch 80 Thickness →

Frequently Asked Questions

What is a pipe schedule and what does it mean?
A pipe schedule (SCH) is a standardized wall thickness designation defined by ASME B36.10 and B36.19. It is related to the pipe's pressure rating — the higher the schedule number, the thicker the wall and the higher the pressure it can handle. Common schedules include SCH 5, 10, 40, 80, 120, and 160. For most standard piping systems, SCH 40 is the default choice.
What is the difference between NPS and DN pipe sizes?
NPS (Nominal Pipe Size) is the North American standard expressed in inches, while DN (Diamètre Nominal) is the international metric designation in millimeters. They represent the same physical pipe — for example, NPS 2 equals DN 50. Both are nominal sizes and do not directly correspond to the actual outer diameter, though NPS 14 and above match the OD in inches.
Does the outer diameter change with different schedules?
No. For a given NPS, the outer diameter (OD) remains constant across all schedules. Only the wall thickness changes. A thicker wall (higher schedule) means a smaller inside diameter (ID). For example, a 2-inch pipe always has an OD of 2.375 inches, but the wall thickness increases from 0.065" (SCH 5) to 0.436" (SCH 160).