tubing 1 e1548871739885

Tubing Dimensions & Weights Charts (by OD & BWG/SWG WT Gauge)

tubing 1 e1548871739885

Tubing Dimensions & Weights Charts (by OD & BWG/SWG WT Gauge)

The article shows the dimensions and weights of tubes between ¼” and 4″ with BWG (Birmingham Wire Gauge) and SWG (Standard Wire Gauge, or Stubs Iron Wire Gauge) wall thickness specifications (Gauges 10-22). BWG and SWG are both gauge measurement systems used to specify the thickness of tubes, as well as wire, in specific industries. Although they originated in the wire industry, these gauges have been adapted to measure the wall thickness of tubing, particularly in contexts where precise control over flow and pressure is required.



BWG (Birmingham Wire Gauge) and SWG (Standard Wire Gauge) are both systems originally developed for measuring the diameter of wires, but they have been adopted in various industries to specify the wall thickness of tubes as well. While they serve similar purposes, there are distinct differences in their scales and where they are predominantly used, especially in the context of tube wall thickness measurement.


  • Usage: BWG is primarily used in the United States and is more common in industries that deal with tube and pipe manufacturing, especially for boilers, heat exchangers, and other metal tubes.
  • Characteristics: The BWG system has a specific set of thicknesses that are widely recognized in the tubing industry for specifying the wall thickness of tubes. The gauge numbers in BWG are assigned to predefined diameters, where a lower gauge number indicates a thicker wall.


  • Usage: SWG is more commonly used in the United Kingdom and other Commonwealth countries. It finds its application across various industries, including jewelry making, wire manufacturing, and tubing, particularly in the electrical field.
  • Characteristics: Like BWG, in the SWG system, a lower gauge number signifies a thicker material. However, the actual thicknesses defined by SWG numbers differ from those in the BWG system for the same gauge number.


  • Scale Variation: The most significant difference between BWG and SWG is in their scale; for the same gauge number, the thickness of the material can differ between the two systems. This variation means that when specifying tube wall thickness, it is crucial to clarify which gauge system is being referenced.
  • Industry Preference: BWG is more frequently used in contexts involving the specification of tube and pipe wall thickness in industries such as petrochemical, heating, and cooling systems. SWG, on the other hand, sees more application in electrical wiring and in countries with historical ties to the British measurement system.

When dealing with tube wall thickness measurements, it’s essential to specify which gauge system is being used to avoid confusion and ensure that materials meet the required specifications. The choice between BWG and SWG may depend on regional preferences, industry standards, or specific project requirements. Always refer to the manufacturer’s specifications or industry standards for accurate and applicable measurements.


Tubing is extensively used in instrumentation across various industries, including oil and gas, chemical processing, power generation, and pharmaceuticals. Instrumentation tubing is crucial for connecting instruments, valves, and other devices in systems designed to measure, monitor, and control process variables such as pressure, flow, temperature, and level.


  • Precision and Reliability: Instrumentation tubing must meet high standards of precision and reliability to ensure accurate signal transmission and fluid transport. It often has tighter tolerances for dimensions and smoother interior surfaces to minimize turbulence and resistance.

  • Material Selection: Stainless steel is the most common material due to its corrosion resistance, strength, and compatibility with a wide range of fluids. Other materials, such as copper, alloy steel, and plastic, are selected based on specific application requirements like chemical compatibility, temperature ranges, and environmental conditions.

  • Size and Configuration: Tubing for instrumentation is typically of small diameter, ranging from 1/4 inch to 1 inch. It is used to connect to fittings that secure and seal the connections between components. The choice of size, wall thickness, and material directly impacts the system’s performance, especially in critical applications where leakage or contamination could have severe consequences.

  • Pressure and Temperature Ratings: The tubing must withstand the operating pressures and temperatures of the system without compromising its integrity or the accuracy of the measurements. Therefore, pressure ratings, temperature limits, and thermal expansion characteristics are key considerations in tubing selection.

  • Safety and Compliance: In many cases, instrumentation tubing and fittings must comply with industry standards and safety regulations, which may specify requirements for design, testing, and material composition to ensure system safety and reliability.

In the realm of instrumentation, tubing plays a vital role in creating efficient, accurate, and safe systems for monitoring and controlling industrial processes. Its selection and installation are critical to system performance, requiring careful consideration of application-specific requirements and adherence to industry standards.



“BWG” Tubing Size Chart: steel tubing sizes by OD (inches/mm) and WT (BWG Gauges 22 to 10), with weight by OD/WT combination in Lbs/ft and Kg/m (according to ASTM A450 Specification)

Tube ODG. 22G. 20G. 18G. 16G.14G. 12

G.  11

G.  10
mm 0.889inch 0.49mm 1.244inch 0.65mm 1.65inch
mm 2.108inch 0.109mm 2.768inch
mm 3.047inch 0.134mm 3.403


“SWG” Tubing Size Chart: steel tubing sizes by OD (inches/mm) and WT (BWG Gauges 22 to 10), with weight by OD/WT combination in Lbs/ft and Kg/m (according to ASTM A450 Specification)

Tube ODG. 22G. 20G. 18G. 16G. 14G. 12G. 11G. 10
mm 0.711inch
mm 0.914inch 0.48mm 1.218inch 0.64mm 1.625inch 0.80mm 2.032inch 0.104mm 2.641inch 0.116mm 2.946inch 0.128mm 3.251


Tube SWG gauge conversion into inches and millimeters

SWGSWG Gauge in inchesSWG Gauge in mm
0 Tube SWG0.3248.23
1 Tube SWG 0.37.62
2 Tube SWG0.2767.01
3 Tube SWG0.2526.4
4 Tube SWG0.2325.89
5 Tube SWG0.2125.38
6 Tube SWG0.1924.88
7 Tube SWG0.1764.47
8 Tube SWG0.164.06
9 Tube SWG0.1443.66
10 Tube SWG1283.25
11 Tube SWG0.1162.95
12 Tube SWG0.1042.64
13 Tube SWG0.0922.34
14 Tube SWG0.082.03
15 Tube SWG0.0721.83
16 Tube SWG0.0641.63
17 Tube SWG0.0561.42
18 Tube SWG0.0481.22
19 Tube SWG0.041.02
20 Tube SWG0.0360.91
21 Tube SWG0.0320.81
22 Tube SWG0.0280.71
23 Tube SWG0.0240.61
24 Tube SWG0.0220.56
25 Tube SWG0.020.51
26 Tube SWG0.0180.46
27 Tube SWG0.01640.42
28 Tube SWG0.01480.38
29 Tube SWG0.01360.35
30 Tube SWG0.01240.31
31 Tube SWG0.01160.29
32 Tube SWG0.01080.27
33 Tube SWG0.010.25
34 Tube SWG0.00920.23
35 Tube SWG0.00840.21
36 Tube SWG0.00760.19

BWGBWG Gauge to inchesBWG Gauge in mm
0 Tube BWG0.348.64
1 Tube BWG 0.37.62
2 Tube BWG0.2847.21
3 Tube BWG0.2596.58
4 Tube BWG0.2386.05
5 Tube BWG0.225.59
6 Tube BWG0.2035.16
7 Tube BWG0.184.57
8 Tube BWG0.1654.19
9 Tube BWG0.1483.76
10 Tube BWG0.1343.4
11 Tube BWG0.123.05
12 Tube BWG0.1092.77
13 Tube BWG0.952.41
14 Tube BWG0.0832.11
15 Tube BWG0.0721.83
16 Tube BWG0.0651.65
17 Tube BWG0.0581.47
18 Tube BWG0.0491.24
19 Tube BWG0.0421.07
20 Tube BWG0.0350.89
21 Tube BWG0.0320.81
22 Tube BWG0.0280.71
23 Tube BWG0.0250.64
24 Tube BWG0.0220.56
25 Tube BWG0.020.51
26 Tube BWG0.0180.46
27 Tube BWG0.0160.41
28 Tube BWG0.0140.36
29 Tube BWG0.0130.33
30 Tube BWG0.0120.3
31 Tube BWG0.010.25
32 Tube BWG0.0090.23
33 Tube BWG0.0080.2
34 Tube BWG0.0070.18
35 Tube BWG0.0050.13
36 Tube BWG0.0040.1

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About the Author

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Projectmaterials Team

Blog.projectmaterials.com is an online resource dedicated to providing in-depth information, analysis, and educational content related to the fields of project materials management, engineering, and procurement, particularly within the oil & gas, construction, shipbuilding, energy, and renewable energy sectors. It aims to serve professionals and enthusiasts in these industries by offering valuable insights into materials, equipment, and techniques used in various projects, focusing on the selection, application, and maintenance of these resources. Key features of the blog include: * Educational Articles: Comprehensive posts that cover topics ranging from the technical aspects of piping products (pipes, valves, fittings, flanges, gaskets, bolts, instrumentation) to structural steel and process equipment (including oil extraction systems, drilling rigs, wellheads, pumps, compressors, and separation systems). * Industry Insights: Updates on the latest trends, technologies, and regulatory changes affecting the industries covered. * Guides and How-Tos: Practical advice on selecting the right materials and equipment for specific applications, as well as tips on installation, maintenance, and troubleshooting. * Safety and Standards: Information on safety equipment for production sites, risk mitigation procedures, and an overview of relevant industry standards and regulatory frameworks. The website is designed to support the professional development of engineers, procurement specialists, project managers, and other stakeholders involved in project plant businesses, by disseminating critical know-how and best practices. Whether readers are new to the field or seasoned professionals, blog.projectmaterials.com offers resources to enhance their understanding and performance in managing project materials effectively.

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9 Responses

  1. Dear Sirs.
    My name is Stacy, I’m a purchasing Manager of an Innotex system company.
    We are a Kazakhstan company, we are engaged in the production and installation of charging stations for electric cars. We opened a representative office in Europe in the field of renewable energy . We are interested in purchasing a metal profile for installation of solar panels. We would buy samples for the test. We are ready to regard the quotation for more quantity
    40*40 – 12 meters, wall thickness 2mm – 1 pc.
    50*50 – 12 meters, wall thickness 2 mm. – 1 pc.
    If that is possible we would like you to deliver that city of Espoo.

  2. Clarified my doubts and provided me the knowledge required to confidently source the material required. top job. Thank You one and all

  3. Dear Sirs/Madams, I believe the wall thickness values, in inches, are a factor of 10x too high for the tubes of gauge 18, 16, 14, and 12. No criticism here; I’ve made many mistakes in my life! Just trying to help.

  4. I pay a quick visit everyday a few web pages and information sites
    to read articles or reviews, however this weblog gives feature based content.

  5. I pay a quick visit everyday a few web pages and information sites
    to read articles or reviews, however this weblog gives feature based content.

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