Square Tube Weight Calculator
Accurately calculate the weight of square hollow sections (SHS) for steel, aluminum, and other metals.
Calculate Tube Weight
Enter dimensions to instantly see weight per piece and total shipment weight.
Metric (mm, meters, kg)
Imperial (inches, feet, lbs)
The outer dimension of the square tube.
Please enter a valid side length.
Thickness of the tube wall.
Thickness must be less than half the side length.
Total length of a single tube.
Steel (Mild) – 7850 kg/m³
Stainless Steel (304/316) – 7900 kg/m³
Aluminum (6061) – 2700 kg/m³
Brass – 8730 kg/m³
Copper – 8960 kg/m³
Select the material to apply the correct density.
Total Weight
0.00 kg
Weight Per Piece
0.00 kg
Cross-Section Area
0.00 cm²
Total Volume
0.00 m³
Formula Used: Weight = (Outer Area – Inner Area) × Length × Density
Specification Summary
| Parameter | Value |
|---|---|
| Material | – |
| Dimensions | – |
| Total Length | – |
| Efficiency (vs Solid) | – |
Weight Comparison Analysis
Comparison of your hollow tube vs. a solid bar of the same outer dimensions.
How to Calculate Square Tube Weight: A Comprehensive Guide
Understanding how to calculate square tube weight is a fundamental skill for structural engineers, metal fabricators, and logistics coordinators. Whether you are estimating shipping costs for a construction project or determining the structural load of a steel frame, accurate weight calculation is critical for safety and budgeting.
This guide provides a deep dive into the mathematics behind square hollow sections (SHS), practical examples, and the key factors that influence the final weight of your materials.
Why Accuracy Matters
Even a small miscalculation in the weight of a single tube can lead to significant discrepancies when multiplied by hundreds of units. This can result in overloaded trucks, under-engineered support structures, or unexpected material costs.
What is Square Tube Weight Calculation?
Calculating the weight of a square tube involves determining the volume of material actually present in the hollow section and multiplying it by the material's density. Unlike solid bars, square tubes (often referred to as Square Hollow Sections or SHS) have a void in the center, which significantly reduces their weight while maintaining high structural rigidity.
This calculation is used by:
- Engineers: To ensure structural integrity without exceeding dead load limits.
- Fabricators: To estimate raw material costs and handling requirements.
- Logistics Managers: To plan shipping capacities and adhere to road weight limits.
Square Tube Weight Formula and Mathematical Explanation
To understand how to calculate square tube weight manually, you must first calculate the volume of the metal shell. The general formula is derived from subtracting the volume of the inner void from the volume of the outer prism.
The Core Formula
The weight ($W$) is calculated as:
W = (A_outer – A_inner) × L × ρ
Where:
- $A_{outer}$: Area of the outer cross-section ($Side^2$)
- $A_{inner}$: Area of the inner void ($(Side – 2 \times Thickness)^2$)
- $L$: Length of the tube
- $\rho$ (Rho): Density of the material
Variables Table
| Variable | Meaning | Metric Unit | Imperial Unit |
|---|---|---|---|
| $S$ | Side Length (Outer) | Millimeters (mm) | Inches (in) |
| $t$ | Wall Thickness | Millimeters (mm) | Inches (in) |
| $L$ | Length | Meters (m) | Feet (ft) |
| $\rho$ | Density | kg/m³ | lbs/in³ |
Practical Examples (Real-World Use Cases)
Example 1: Steel Structural Column
A construction project requires 10 pieces of mild steel square tubing. The dimensions are 100mm x 100mm with a 5mm wall thickness. Each piece is 6 meters long.
- Outer Area: $100 \times 100 = 10,000 \, mm^2$
- Inner Dimension: $100 – (2 \times 5) = 90 \, mm$
- Inner Area: $90 \times 90 = 8,100 \, mm^2$
- Cross-Section Area: $10,000 – 8,100 = 1,900 \, mm^2$ ($0.0019 \, m^2$)
- Volume per Piece: $0.0019 \, m^2 \times 6 \, m = 0.0114 \, m^3$
- Weight per Piece: $0.0114 \times 7850 \, kg/m^3 \approx 89.49 \, kg$
- Total Weight: $89.49 \times 10 = 894.9 \, kg$
Example 2: Aluminum Frame for Shipping
You are fabricating a lightweight frame using Aluminum 6061. You need a 2-inch square tube with 0.125-inch wall thickness, 10 feet long.
- Outer Area: $2 \times 2 = 4 \, sq \, in$
- Inner Dimension: $2 – (2 \times 0.125) = 1.75 \, in$
- Inner Area: $1.75 \times 1.75 = 3.0625 \, sq \, in$
- Metal Area: $4 – 3.0625 = 0.9375 \, sq \, in$
- Volume: $0.9375 \, sq \, in \times 120 \, in \, (10ft) = 112.5 \, cu \, in$
- Weight: $112.5 \times 0.0975 \, lbs/cu \, in \approx 10.97 \, lbs$
How to Use This Square Tube Weight Calculator
Our tool simplifies the complex math into a few clicks. Follow these steps to get an instant result:
- Select System: Choose between Metric (mm/kg) or Imperial (inches/lbs) based on your blueprints.
- Enter Dimensions: Input the outer side length and the wall thickness. Ensure the thickness is less than half the side length.
- Input Length: Enter the length of a single tube.
- Choose Material: Select the metal type. This automatically applies the correct density (e.g., 7850 kg/m³ for steel).
- Review Results: The calculator displays the weight per piece, total weight for the quantity entered, and a visual comparison against a solid bar.
Key Factors That Affect Square Tube Weight Results
When learning how to calculate square tube weight, consider these variables that can alter the theoretical weight versus the actual weight:
1. Material Density Variations
Not all steel is created equal. While 7850 kg/m³ is the standard for mild steel, stainless steel grades like 304 or 316 are slightly denser (approx. 7900 kg/m³). Aluminum alloys also vary slightly in density.
2. Corner Radius
Square tubes are rarely perfectly sharp at the corners. The manufacturing process (rolling) creates rounded corners. This removes a small amount of material compared to a perfect geometric square, meaning the actual weight is often slightly less than the theoretical calculation.
3. Manufacturing Tolerances
ASTM and ISO standards allow for slight deviations in wall thickness and side dimensions. A tube sold as "5mm thick" might actually be 4.8mm or 5.2mm, affecting the total weight by up to 5-10%.
4. Surface Coatings
Galvanization, painting, or powder coating adds weight. For heavy structural steel, zinc galvanization can add 3-5% to the total weight, which must be accounted for in precision lifting.
5. Length Precision
Cutting tolerances affect weight. If a supplier cuts tubes slightly longer than specified to ensure they aren't too short, the total shipment weight will increase.
6. Weld Seams
In welded hollow sections, the internal weld bead adds a small amount of material that isn't accounted for in simple geometric formulas.
Frequently Asked Questions (FAQ)
Q: Does this calculator account for the corner radius?
A: This calculator uses the standard geometric formula for a square profile. For high-precision engineering requiring corner radius adjustments, the weight is typically 1-3% lower than the theoretical square calculation.
A: This calculator uses the standard geometric formula for a square profile. For high-precision engineering requiring corner radius adjustments, the weight is typically 1-3% lower than the theoretical square calculation.
Q: What is the density of mild steel vs. stainless steel?
A: Mild steel is typically calculated at 7850 kg/m³ (0.2836 lbs/in³), while Stainless Steel is slightly heavier at roughly 7900-8000 kg/m³ depending on the grade.
A: Mild steel is typically calculated at 7850 kg/m³ (0.2836 lbs/in³), while Stainless Steel is slightly heavier at roughly 7900-8000 kg/m³ depending on the grade.
Q: Can I calculate rectangular tube weight with this tool?
A: This specific tool is for square tubes (Side A = Side B). For rectangular tubes, you would need to calculate the area as $(Width \times Height) – ((Width-2t) \times (Height-2t))$.
A: This specific tool is for square tubes (Side A = Side B). For rectangular tubes, you would need to calculate the area as $(Width \times Height) – ((Width-2t) \times (Height-2t))$.
Q: Why is the wall thickness limited in the input?
A: The wall thickness cannot exceed half of the side length. If it did, the hole in the middle would disappear or overlap, which is physically impossible.
A: The wall thickness cannot exceed half of the side length. If it did, the hole in the middle would disappear or overlap, which is physically impossible.
Q: How do I convert the result from kg to lbs?
A: 1 kilogram equals approximately 2.20462 pounds. Multiply your metric result by 2.20462 to get pounds.
A: 1 kilogram equals approximately 2.20462 pounds. Multiply your metric result by 2.20462 to get pounds.
Q: Is aluminum strong enough to replace steel tubing?
A: Aluminum is roughly 1/3 the weight of steel but also has lower strength. You often need a thicker wall or larger dimension in aluminum to match the strength of a thinner steel tube.
A: Aluminum is roughly 1/3 the weight of steel but also has lower strength. You often need a thicker wall or larger dimension in aluminum to match the strength of a thinner steel tube.
Q: How does galvanization affect the weight?
A: Hot-dip galvanization typically adds about 300-600 grams per square meter of surface area, roughly increasing the total weight by 3-5%.
A: Hot-dip galvanization typically adds about 300-600 grams per square meter of surface area, roughly increasing the total weight by 3-5%.
Q: What is the difference between SHS and RHS?
A: SHS stands for Square Hollow Section, while RHS stands for Rectangular Hollow Section. The calculation logic is similar, but SHS has equal sides.
A: SHS stands for Square Hollow Section, while RHS stands for Rectangular Hollow Section. The calculation logic is similar, but SHS has equal sides.
Related Tools and Internal Resources
- Metal Weight Calculator – Calculate weights for plates, bars, and rounds.
- Standard Steel Tube Sizes – A chart of common ASTM and ISO tube dimensions.
- Structural Engineering Basics – Learn about load calculations and safety factors.
- Material Density Chart – Comprehensive list of densities for metals and alloys.
- Shipping Cost Estimator – Estimate logistics costs based on material weight.
- Pipe Schedule Chart – Reference for standard pipe thicknesses and diameters.