Carbon Steel Square Tube Size Chart

Carbon steel (CS) square tubes, also known as Square Hollow Sections (SHS), are widely used in structural construction, machinery manufacturing, infrastructure, and general fabrication due to their high strength-to-weight ratio, excellent weldability, and cost-effectiveness. They are available in a broad range of outside dimensions, wall thicknesses, lengths, and material grades to meet different engineering requirements.

This guide provides standard carbon steel square tube dimensions in both metric (mm) and imperial (inch) units, together with wall thicknesses, theoretical weights, dimensional tolerances, and common supply specifications to help engineers, fabricators, and purchasers compare available sizes efficiently.

What Is a Carbon Steel Square Tube?

A carbon steel square tube (SHS) is a hollow structural section with a square cross-section, manufactured from carbon steel . Unlike round steel pipes specified by schedule numbers, square tubes are designated by their outside dimensions (width × width) and wall thickness.

Square tubes are typically formed from steel coil and welded from the inside to form their shape. Common manufacturing processes include:

● Cold-formed welded (most common)
● Seamless (available for selected sizes)

They are used for structural and mechanical purposes, including building construction, equipment frames, railings, sign posts, and heavy infrastructure projects.

Standard Square Tube Size Chart

Imperial Carbon Steel Square Tube Sizes (ASTM A500)

Imperial sizes are primarily used in the North American market and are commonly manufactured to ASTM A500 Grade B and Grade C specifications for structural hollow sections.

Size (in)	Wall Thickness (in)	Weight (lbs/ft)	Standard Length (ft)
1/2 × 1/2	0.063	0.38	20 / 24
3/4 × 3/4	0.063	0.61	20 / 24
1 × 1	0.063	0.83	20 / 24
1 × 1	0.125	1.35	20 / 24
1 1/2 × 1 1/2	0.063	1.27	20 / 24
1 1/2 × 1 1/2	0.125	2.21	20 / 24
1 1/2 × 1 1/2	0.188	3.05	20 / 24
1 1/2 × 1 1/2	0.250	4.42	20 / 24
2 × 2	0.063	1.69	20 / 24 / 40
2 × 2	0.125	3.06	20 / 24 / 40
2 × 2	0.188	4.33	20 / 24 / 40
2 × 2	0.250	5.41	20 / 24 / 40
3 × 3	0.125	4.76	20 / 24 / 40
3 × 3	0.188	6.89	20 / 24 / 40
3 × 3	0.250	8.81	20 / 24 / 40
3 × 3	0.375	12.17	20 / 24 / 40
4 × 4	0.125	6.46	20 / 24 / 40 / 48
4 × 4	0.188	9.45	20 / 24 / 40 / 48
4 × 4	0.250	12.21	20 / 24 / 40 / 48
4 × 4	0.375	17.27	20 / 24 / 40 / 48
4 × 4	0.500	21.63	20 / 24 / 40 / 48
6 × 6	0.188	14.56	20 / 24 / 40 / 48
6 × 6	0.250	19.02	20 / 24 / 40 / 48
6 × 6	0.375	27.48	20 / 24 / 40 / 48
6 × 6	0.500	35.24	20 / 24 / 40 / 48
8 × 8	0.250	25.82	20 to 48
8 × 8	0.375	37.69	20 to 48
8 × 8	0.500	48.45	20 to 48
10 × 10	0.250	32.60	20 to 48
10 × 10	0.375	47.90	20 to 48
10 × 10	0.500	62.20	20 to 48
12 × 12	0.250	39.43	20 to 48
12 × 12	0.500	76.07	20 to 48
12 × 12	0.625	93.34	20 to 48
16 × 16	0.375	78.52	Up to 60
16 × 16	0.500	103.30	Up to 60
16 × 16	0.625	127.36	Up to 60

Metric Carbon Steel Square Tube Sizes (EN 10219 / GB/T 6728)

Metric square tube sizes are widely used throughout Europe, Asia, Australia, and international engineering projects. These products are commonly manufactured to EN 10219 (cold-formed) or EN 10210 (hot-finished), GB/T 6728, and AS/NZS 1163 standards.

Size (mm)	Wall Thickness (mm)	Weight (kg/m)	Standard Length (m)
20 × 20	2.0	1.05	6
20 × 20	2.5	1.25	6
25 × 25	2.0	1.36	6
25 × 25	3.0	1.89	6
30 × 30	2.0	1.68	6
30 × 30	3.0	2.40	6
40 × 40	2.0	2.30	6 / 8
40 × 40	3.0	3.30	6 / 8
40 × 40	4.0	4.20	6 / 8
50 × 50	2.0	2.90	6 / 8
50 × 50	3.0	4.30	6 / 8
50 × 50	4.0	5.50	6 / 8
50 × 50	5.0	6.60	6 / 8
60 × 60	3.0	5.20	6 / 8
60 × 60	4.0	6.70	6 / 8
60 × 60	5.0	8.10	6 / 8
60 × 60	6.0	9.50	6 / 8
75 × 75	3.0	6.64	6 / 8 / 12
75 × 75	5.0	10.51	6 / 8 / 12
80 × 80	4.0	9.20	6 / 8 / 12
80 × 80	6.0	13.20	6 / 8 / 12
100 × 100	3.0	9.00	6 / 8 / 12
100 × 100	5.0	14.40	6 / 8 / 12
100 × 100	6.0	17.00	6 / 8 / 12
100 × 100	8.0	21.40	6 / 8 / 12
120 × 120	4.0	14.10	8 / 12
120 × 120	6.0	20.70	8 / 12
150 × 150	5.0	22.60	8 / 12
150 × 150	6.0	26.46	8 / 12
150 × 150	8.0	34.62	8 / 12
150 × 150	10.0	42.33	8 / 12
200 × 200	6.0	35.88	12 / 15
200 × 200	10.0	58.03	12 / 15
200 × 200	12.5	71.07	12 / 15
250 × 250	8.0	60.30	12 / 15
250 × 250	12.5	91.90	12 / 15
300 × 300	10.0	90.20	12 / 15
300 × 300	12.5	110.31	12 / 15
300 × 300	16.0	138.96	12 / 15
400 × 400	12.5	151.00	12 to 18
400 × 400	16.0	189.00	12 to 18
500 × 500	12.5	189.00	12 to 18

Recommended Square Tube Sizes by Application:

The following table provides general recommendations for selecting carbon steel square tube sizes based on common application requirements. Final selection should always be verified against specific design loads, applicable building codes, and engineering standards.

Application	Recommended Size Range	Typical Wall Thickness	Notes
Furniture & Decorative Frames	20×20 – 40×40 mm	1.0 – 2.0 mm	Lightweight, aesthetic finish preferred.
Handrails, Fences & Guardrails	30×30 – 50×50 mm	1.5 – 3.0 mm	Requires good weldability and surface finish.
Light Machinery Frames & Supports	50×50 – 100×100 mm	3.0 – 6.0 mm	Moderate strength needed; good balance of weight and rigidity.
Structural Columns & Heavy Equipment Frames	100×100 – 200×200 mm	4.0 – 10.0 mm	High strength; design should comply with structural codes (e.g., AISC).
Heavy Civil Structures & Bridges	≥200×200 mm	≥8.0 mm	Load-bearing design required; consult structural engineer.

Dimensional Tolerances (ASTM A500 vs. EN 10219)

Manufacturing tolerances ensure dimensional consistency and interchangeability for structural fabrication. The exact allowable deviations depend on the applicable manufacturing standard.

Item	ASTM A500	EN 10219
Outside Dimensions	±1% (or ±0.020", whichever is greater)	±1%
Wall Thickness	±10%	±10%
Straightness	1/8 in per 5 ft	0.2% of total length
Squareness (Corners)	90° ± 1.5°	90° ± 1.5°
Mass Tolerance	-3.5%	-3.5%

Standard Specifications & Materials

Carbon steel square tubes are available in a variety of material grades and manufacturing standards.

Parameter	Specification
Product Type	Welded Square Hollow Section (SHS), Seamless (selected sizes)
Outside Dimensions	10 × 10 mm to 500 × 500 mm (custom sizes available)
Wall Thickness	0.5 mm to 25 mm
Standard Length	6 m, 9 m, 12 m / 20 ft, 24 ft, 40 ft, 48 ft (custom cut lengths available)
Material Grades	Q195, Q235, Q355, A500 Grade A/B/C, ASTM A36, S235, S355
Manufacturing Standards	ASTM A500, ASTM A501, ASTM A513, EN 10219, EN 10210, JIS G3466, GB/T 6728
Surface Finish	Black, Oiled, Pickled, Hot-dip Galvanized, Primer Painted
End Finish	Plain Ends, Deburred Ends, Cut to Length
Inspection	Visual, Dimensional, Mechanical Testing, Chemical Analysis (upon request)
Certification	Mill Test Certificate (EN 10204 3.1), Third-party Inspection Available
Packaging	Steel Strapping, Bundles, Waterproof Packing, Export Seaworthy Packaging

Square Tube Dimensions by Standard:

Carbon steel square tube dimensions are classified according to different manufacturing standards. The table below summarizes the primary standard systems, their typical size ranges, and common applications.

Standard System	Standards	Size Range	Typical Applications
American (ASTM)	ASTM A500 (Cold-formed), ASTM A501 (Hot-formed)	1/2" × 1/2" to 32" × 32" (custom sizes up to 800mm)	Structures, bridges, general fabrication in North America
European (EN)	EN 10219 (Cold-formed), EN 10210 (Hot-finished)	20×20 mm to 500×500 mm	Structural and mechanical applications in Europe & international projects
Chinese (GB/T)	GB/T 6728, GB/T 3094	20×20 mm to 600×600 mm	Building structures, machinery, chemical equipment in China
Japanese (JIS)	JIS G 3466	20×20 mm to 400×400 mm	Structural uses in Japan and Asian markets
Australian (AS/NZS)	AS/NZS 1163	Similar to EN range	Structural applications in Australia & New Zealand

Square Tube Theoretical Weight Calculation:

The theoretical weight of a carbon steel square tube can be calculated using the following formula:

For metric units (kg/m):
Weight (kg/m) = [4 × (Side A - Wall Thickness) × Wall Thickness × 0.00785]

Where: Side A is the outside dimension (mm), Wall Thickness is in mm, and 0.00785 is the density of carbon steel (g/mm³).

For imperial units (lbs/ft):
Weight (lbs/ft) = [4 × (Side A - Wall Thickness) × Wall Thickness × 0.284]

Where: Side A is the outside dimension (in), Wall Thickness is in inches, and 0.284 is the density of carbon steel (lbs/in³).

Example (Metric): 

For a 100 × 100 mm square tube with a 5 mm wall thickness:
Weight = [4 × (100 - 5) × 5 × 0.00785] = 14.92 kg/m

Note: The values calculated are theoretical weights. Actual product weight may vary by approximately ±3.5% due to manufacturing tolerances as per ASTM A500 and EN 10219 standards. For stainless steel or other materials, use the corresponding density coefficient.

Frequently Asked Questions (FAQ):

Q1: What are the standard sizes of carbon steel square tubes?
A: Standard metric sizes range from 10 × 10 mm to 500 × 500 mm. Imperial sizes range from 1/2 × 1/2 in to 22 × 22 in. Wall thickness varies by size and standard .

Q2: What is the standard length of carbon steel square tubing?
A: Metric products are typically 6 m, 9 m, or 12 m. Imperial products are commonly 20 ft, 24 ft, 40 ft, or 48 ft. Custom cut lengths are available from most manufacturers .

Q3: What wall thicknesses are available?
A: Wall thickness typically ranges from 0.5 mm to 25 mm, depending on tube size and applicable standard. Larger sections are generally produced with thicker walls for higher structural strength .

Q4: What are the most common manufacturing standards?
A: The most common standards include ASTM A500 (North America), EN 10219/EN 10210 (Europe), GB/T 6728 (China), and JIS G3466 (Japan) .

Q5: How is the weight of a carbon steel square tube determined?
A: Theoretical weight is calculated based on outside dimensions and wall thickness. Standard weight tables provide quick estimates, while custom sizes require specific calculations .

Q6: Can carbon steel square tubes be supplied in custom sizes?
A: Yes. Manufacturers can provide custom lengths, wall thicknesses, and surface treatments based on project requirements.

Conclusion:

Carbon steel square tubes are available in a wide range of standard dimensions, wall thicknesses, lengths, and material grades to meet different structural and mechanical requirements. This guide provides a comprehensive reference for engineers, fabricators, and purchasers to select the appropriate square tube for their projects.

Need a size not listed above? Contact us for custom dimensions, lengths, and project-specific manufacturing solutions.

Related Resources:
● What is Black Square Tubing?
● What is MS Square Tube? A Complete Guide
● How to Calculate Weight of Square Pipes (RHS/SHS)
● Rectangular Tube vs. Square Tube: Which Has a Better Load-bearing Capacity?