Square Tube Weight Chart: Weight per Meter and per Foot

The weight of a square tube depends on its outside dimension, wall thickness, and material density. This guide gives you a square tube weight chart in kg/m and lb/ft for common metric and inch sizes, the formula for calculating square tube weight per meter, and a worked example. As a quick reference, a 50 × 50 × 3 mm carbon steel tube weighs about 4.43 kg/m (2.98 lb/ft), and a 2 × 2 × 1/8 in tube weighs about 3.19 lb/ft. Use the chart to estimate weights before you request a quotation for square steel pipe.

Square Tube Weight Chart (kg/m and lb/ft)

All values below are calculated theoretical weights for carbon steel (density 7.85 g/cm³), based on nominal dimensions and the formula in the next section. They are estimates, not standard-specified weights. The lb/ft values are converted from the unrounded kg/m result, so converting the rounded kg/m values shown here may differ by 0.01 lb/ft. Because the formula ignores corner radii, figures from a supplier’s standard weight table may differ slightly.

Outside Size (mm)	Wall Thickness (mm)	Weight (kg/m)	Weight (lb/ft)
20 × 20	1.2	0.71	0.48
20 × 20	1.5	0.87	0.59
20 × 20	2.0	1.13	0.76
25 × 25	1.5	1.11	0.74
25 × 25	2.0	1.44	0.97
25 × 25	2.5	1.77	1.19
30 × 30	1.5	1.34	0.90
30 × 30	2.0	1.76	1.18
30 × 30	3.0	2.54	1.71
40 × 40	2.0	2.39	1.60
40 × 40	2.5	2.94	1.98
40 × 40	3.0	3.49	2.34
40 × 40	4.0	4.52	3.04
50 × 50	2.0	3.01	2.03
50 × 50	3.0	4.43	2.98
50 × 50	4.0	5.78	3.88
50 × 50	5.0	7.07	4.75
60 × 60	2.5	4.51	3.03
60 × 60	3.0	5.37	3.61
60 × 60	4.0	7.03	4.73
60 × 60	5.0	8.64	5.80
80 × 80	3.0	7.25	4.87
80 × 80	4.0	9.55	6.41
80 × 80	5.0	11.78	7.91
80 × 80	6.0	13.94	9.37
100 × 100	3.0	9.14	6.14
100 × 100	4.0	12.06	8.10
100 × 100	5.0	14.92	10.02
100 × 100	6.0	17.71	11.90
100 × 100	8.0	23.11	15.53
120 × 120	4.0	14.57	9.79
120 × 120	5.0	18.06	12.13
120 × 120	6.0	21.48	14.43
120 × 120	8.0	28.13	18.91
150 × 150	5.0	22.77	15.30
150 × 150	6.0	27.13	18.23
150 × 150	8.0	35.67	23.97
150 × 150	10.0	43.96	29.54

Square Tubing Weight per Foot (Inch Sizes)

Inch sizes below use the same idealized formula, with dimensions in inches: Weight (lb/ft) ≈ [B² − (B − 2t)²] × 3.4034, where B and t are in inches. The coefficient 3.4034 is the metric coefficient converted to inches and feet. These are theoretical estimates for carbon steel, not standard-specified weights. Wall thicknesses are shown as fractions, not gauge numbers.

Outside Size (in)	Wall Thickness (in)	Weight (lb/ft)	Weight (kg/m)
1 × 1	1/16	0.80	1.19
1 × 1	1/8	1.49	2.22
1½ × 1½	1/8	2.34	3.48
1½ × 1½	3/16	3.35	4.99
2 × 2	1/8	3.19	4.75
2 × 2	3/16	4.63	6.88
2 × 2	1/4	5.96	8.86
3 × 3	3/16	7.18	10.68
3 × 3	1/4	9.36	13.93
3 × 3	3/8	13.40	19.94
4 × 4	1/4	12.76	18.99
4 × 4	3/8	18.51	27.54
4 × 4	1/2	23.82	35.45

Example: For a 2 × 2 × 1/8 in tube, 4 × 0.125 × (2 − 0.125) = 0.9375 in², and 0.9375 × 3.4034 = about 3.19 lb/ft.
For other sizes, use the formula below. 

Square Tube Weight Formula

You can estimate square steel tube weight, meaning the theoretical weight of a hollow square section, with this formula:

Weight (kg/m) ≈ [B² − (B − 2t)²] × 0.00785

Where:

• B = outside dimension of the square tube, in mm
• t = wall thickness, in mm
• 0.00785 = approximate coefficient based on carbon steel density of 7.85 g/cm³

The formula treats the tube as a perfect square ring with sharp corners. Real tubes have rounded corners, so the result can differ slightly from a standard theoretical weight table or from the weight you measure on a scale.

To find square tubing weight per foot, convert from kg/m:

Weight (lb/ft) = Weight (kg/m) × 0.672

In this article, “theoretical weight” means a value calculated from nominal size and wall thickness. “Actual weight” is what a scale reads, and it can differ because of tolerances, corner radius and coating.

If you want a simple square tube weight calculator, paste these formulas into a spreadsheet, with outside size in A2 and wall thickness in B2 (both in mm):

• kg/m: =(A2^2-(A2-2*B2)^2)*0.00785

• lb/ft: =(A2^2-(A2-2*B2)^2)*0.00785*0.672

Square Tube Weight Calculation Example

Calculate the weight of a 50 × 50 × 3 mm square tube.

1. Outside dimension: B = 50 mm
2. Wall thickness: t = 3 mm
3. Inner dimension: B − 2t = 50 − 6 = 44 mm
4. Outer area: 50² = 2,500
5. Inner area: 44² = 1,936
6. Difference: 2,500 − 1,936 = 564
7. Weight per meter: 564 × 0.00785 = 4.4274, rounded to 4.43 kg/m
8. Weight per foot: 4.4274 × 0.672 = 2.98 lb/ft

This matches the 50 × 50 × 3.0 row in the chart above, because the chart uses the same formula. A standard table that accounts for corner radii may show a slightly different value for the same size.

What Affects Square Tube Weight?

Outside dimensions: A larger outside size means more steel in the cross-section, so weight rises with size.

Wall thickness: This has the biggest effect at a given size. For example, going from 3 mm to 5 mm wall on a 50 × 50 tube raises the weight from 4.43 to 7.07 kg/m, an increase of about 60%, while the outside size stays the same.

Steel density and material type: The formula assumes carbon steel at 7.85 g/cm³. Stainless steel is slightly denser, so the same size will weigh somewhat more.

Corner radius and manufacturing tolerances: Rounded corners and allowed variation in wall thickness and dimensions cause small differences from the idealized weight.

Galvanized coating or other surface treatment: A zinc coating or other treatment adds a small amount of weight. Ask your supplier whether quoted weights include it.

How to Use the Square Tube Weight Chart

Find the outside size and wall thickness you need in the metric or inch table. If the exact size is missing, calculate it with the formula. For inch sizes outside the table, convert to mm first (1 in = 25.4 mm).
Read the weight per meter (or per foot).
Multiply by the length of one piece to get the single-piece weight.
Multiply by the number of pieces to get the total weight.

Example: You need 200 pieces of 50 × 50 × 3 mm tube, each 6 m long.

• Weight per piece: 4.4274 kg/m × 6 m = 26.56 kg
• Total length: 200 × 6 m = 1,200 m
• Total weight: 4.4274 kg/m × 1,200 m = about 5,313 kg (5.31 tonnes)

These figures are theoretical. For purchasing, always confirm the size, standard, tolerance and weight basis with your supplier. If you also need to check whether a size is suitable for a load, see our article on square tube load capacity and strength calculation.

FAQs

How do you calculate square tube weight per meter?

Use Weight (kg/m) ≈ [B² − (B − 2t)²] × 0.00785, where B is the outside size in mm and t is the wall thickness in mm. For a 50 × 50 × 3 mm tube, the result is about 4.43 kg/m.

How much does a square steel tube weigh per foot?

Multiply the weight in kg/m by 0.672. A 50 × 50 × 3 mm carbon steel tube weighs about 2.98 lb/ft. For inch sizes, a 2 × 2 × 1/8 in tube weighs about 3.19 lb/ft; see the inch table above.

Does wall thickness affect square tube weight?

Yes. At the same outside size, a thicker wall means more steel and a higher weight. A 50 × 50 tube weighs about 4.43 kg/m at 3 mm and about 7.07 kg/m at 5 mm.

Is the calculated square tube weight the same as actual weight?

Not exactly. The calculated value is a theoretical weight. Actual weight varies with corner radius, wall thickness tolerance, material density and any coating.

How do you calculate the total weight of square tubing?

Multiply the weight per meter by the length of each piece and by the number of pieces. For 200 pieces of 50 × 50 × 3 mm tube at 6 m each, the total is about 5,313 kg.

Related articles:

Square Tube Thickness