Square Steel Tube Weight Calculator
Accurately calculate weight of square steel tube in kg
Calculator
Enter your dimensions below to instantly calculate the total weight.
The outer width of one side of the square tube.
Please enter a valid width.
Thickness of the steel wall. Must be less than half the width.
Thickness must be less than half the width (Radius).
Total length of the tube in meters.
Number of tubes needed.
Standard Mild Steel is approx 7850 kg/m³.
Total Weight
0.00 kg
Weight Per Meter
0.00 kg/m
Total Volume
0.000 m³
Surface Area
0.00 m²
Used Formula: Weight = [Side² – (Side – 2×Thickness)²] × Length × Density
Efficiency Comparison: Hollow vs. Solid
This chart compares your hollow tube against a solid steel bar of the same dimensions.
Specification Summary
| Parameter | Value | Unit |
|---|
What is how to calculate weight of square steel tube in kg?
Understanding how to calculate weight of square steel tube in kg is a fundamental skill for engineers, fabricators, construction estimators, and logistics managers. In the steel industry, weight is the primary currency—material is bought, sold, and shipped based on mass. Square steel tubing, also known as Square Hollow Section (SHS), provides an excellent balance of strength and weight compared to solid bars.
This calculation determines the mass of a hollow steel prism based on its dimensions and the density of the material. Whether you are estimating the load for a transport truck, calculating the dead load on a structural beam, or simply budgeting for raw materials, an accurate weight calculation prevents costly errors and safety hazards.
Common misconceptions include assuming that the weight scales linearly with width (it actually scales with the cross-sectional area) or neglecting the specific density of different steel grades. While standard mild steel is the norm, stainless steel or galvanized coatings can slightly alter the final figures.
Square Tube Weight Formula and Mathematical Explanation
To master how to calculate weight of square steel tube in kg, one must look at the geometry of the object. A square tube is essentially a smaller square prism removed from the center of a larger square prism.
The standard formula is derived as follows:
- Calculate Outer Volume: $V_{outer} = Width \times Width \times Length$
- Calculate Inner Volume: $V_{inner} = (Width – 2 \times Thickness)^2 \times Length$
- Find Steel Volume: $V_{steel} = V_{outer} – V_{inner}$
- Convert to Weight: $Weight = V_{steel} \times Density$
Mathematically, for a single tube, the formula is:
Weight (kg) = [ (A/1000)² – ((A – 2t)/1000)² ] × L × ρ
| Variable | Meaning | Unit Used in Formula | Typical Range |
|---|---|---|---|
| A | Outer Side Width | Meters (input usually mm) | 20mm – 400mm |
| t | Wall Thickness | Meters (input usually mm) | 1.5mm – 20mm |
| L | Length | Meters | 6m, 12m (Standard Stock) |
| ρ (Rho) | Density | kg/m³ | 7850 (Mild Steel) |
Practical Examples (Real-World Use Cases)
Example 1: Residential Gate Fabrication
A fabricator needs to build a driveway gate using 50mm square tubing. They have 10 pieces, each 6 meters long, with a wall thickness of 3mm.
- Input: Width = 50mm, Thickness = 3mm, Length = 6m, Qty = 10.
- Calculation:
Outer Area = $0.05 \times 0.05 = 0.0025 m^2$
Inner Width = $50 – (2 \times 3) = 44mm = 0.044m$
Inner Area = $0.044 \times 0.044 = 0.001936 m^2$
Steel Area = $0.0025 – 0.001936 = 0.000564 m^2$
Volume per tube = $0.000564 \times 6 = 0.003384 m^3$
Weight per tube = $0.003384 \times 7850 = 26.56 kg$ - Result: Total weight for 10 tubes is roughly 265.6 kg. This helps determine if a small utility trailer can transport the load legally.
Example 2: Structural Column Load
An engineer is calculating the dead load of a heavy-duty column. They use a 200mm x 200mm SHS with 10mm thickness, standing 4 meters tall.
- Input: Width = 200mm, Thickness = 10mm, Length = 4m.
- Result: The calculator would show a weight of approximately 238.5 kg. This figure is crucial for the foundation design calculations.
How to Use This Square Steel Tube Calculator
We designed this tool to simplify the process of how to calculate weight of square steel tube in kg. Follow these steps:
- Enter Dimensions: Input the outer side width and wall thickness in millimeters (mm). These are standard units found on engineering drawings.
- Set Length: Input the length of the tube in meters. If you have a custom cut length, use decimal points (e.g., 2.5 meters).
- Verify Density: The default is set to 7850 kg/m³, which is the industry standard for mild carbon steel. If you are using Stainless Steel (304/316), you might adjust this to roughly 7900-8000 kg/m³.
- Analyze Results: The tool instantly provides the total weight, weight per meter, and surface area.
Use the "Copy Results" button to paste the data directly into your invoice, bill of materials (BOM), or engineering report.
Key Factors That Affect Steel Weight Results
When learning how to calculate weight of square steel tube in kg, consider these six financial and physical factors:
- Manufacturing Tolerances: Steel mills have a tolerance range. A tube sold as "3mm thick" might effectively be 2.9mm or 3.1mm, affecting the actual weight by ±5%.
- Corner Radius: Our calculator assumes square corners for simplicity (theoretical weight). In reality, SHS tubes have rounded corners, which slightly reduces the actual weight compared to the theoretical square corner calculation.
- Material Composition: Different alloys have different densities. Aluminum square tubes, for example, are roughly 1/3 the weight of steel.
- Galvanization: Hot-dip galvanizing adds zinc to the surface, typically increasing the weight by 3-5%. This is critical for logistics pricing.
- Shipping Costs: Freight is often charged by weight. Accurately knowing the total kg allows for precise shipping cost estimation.
- Scrap Rates: If you are cutting tubes, you calculate the weight of the raw stock. The "useful" weight in the final product will be lower, but you pay for the full length.
Frequently Asked Questions (FAQ)
Why does the corner radius matter for weight calculation?
Real square tubes have rounded edges. This missing material at the corners means the actual weight is slightly less than the theoretical weight calculated using sharp corners. For most estimates, the difference is negligible (< 3%), but for massive orders, it adds up.
Can I use this for aluminum or stainless steel?
Yes. Simply change the "Material Density" field. Use ~2700 kg/m³ for Aluminum and ~7930 kg/m³ for Stainless Steel.
What is the standard density of mild steel?
The industry standard accepted value is 7850 kg/m³ (7.85 g/cm³).
How do I calculate the weight of a hollow rectangular tube?
This calculator is for square tubes. For rectangles, you need separate inputs for Width A and Height B. The logic remains the same: (Outer Area – Inner Area) × Length × Density.
Does this include the weight of welding filler?
No, this calculates the raw material weight of the tube itself. Weld weight is calculated separately based on weld volume.
Why is "Weight Per Meter" important?
Engineers use kg/m to check structural efficiency. It allows them to compare different tube sizes to find the lightest profile that meets strength requirements.
Is nominal size the same as actual size?
Not always. Structural steel standards (like ASTM A500 or EN 10219) allow for specific deviations. Always check the mill certificate for exact dimensions.
What is the difference between SHS and RHS?
SHS stands for Square Hollow Section (equal sides). RHS stands for Rectangular Hollow Section (unequal sides). This tool is specifically for SHS.
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