RHS Steel Weight Calculator
Professional Rectangular Hollow Section Mass & Cost Estimator
Formula Used: Weight = (Outer Area – Inner Area) × Length × Density
| Specification | Value |
|---|
Comparison of your RHS selection vs. a solid bar of the same outer dimensions.
Comprehensive Guide to the RHS Steel Weight Calculator
In the world of structural engineering, construction, and metal fabrication, precision is paramount. Whether you are estimating transport costs, checking structural loads, or budgeting for raw materials, knowing the exact mass of your components is critical. This rhs steel weight calculator is designed to provide instant, accurate estimations for Rectangular Hollow Sections (RHS), helping professionals make informed decisions.
What is an RHS Steel Weight Calculator?
An rhs steel weight calculator is a digital tool used to compute the theoretical mass of Rectangular Hollow Sections based on their geometric dimensions and material density. RHS is a popular choice in construction due to its high strength-to-weight ratio and aesthetic appeal in exposed structures.
This tool is essential for:
- Structural Engineers: To calculate dead loads for building design.
- Estimators: To determine material costs based on weight-based pricing.
- Logistics Managers: To plan shipping requirements and ensure vehicles are not overloaded.
- Fabricators: To estimate lifting requirements and crane capacities.
RHS Steel Weight Calculator Formula and Math
The calculation behind the rhs steel weight calculator relies on determining the volume of material in the section and multiplying it by the density of the material. The formula essentially subtracts the volume of the inner "void" from the volume of the outer "box".
The Core Formula
The weight ($W$) is calculated as follows:
$$ W = \text{Area} \times \text{Length} \times \text{Density} $$
Where the Cross-Sectional Area ($A$) is:
$$ A = (Width_{outer} \times Height_{outer}) – (Width_{inner} \times Height_{inner}) $$
Given that the inner dimensions are determined by the wall thickness ($t$):
$$ Width_{inner} = Width_{outer} – 2t $$
$$ Height_{inner} = Height_{outer} – 2t $$
Variables Table
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| $W$ | Total Weight | kg | – |
| $A$ | Outer Width | mm | 50mm – 400mm |
| $B$ | Outer Height | mm | 20mm – 300mm |
| $t$ | Wall Thickness | mm | 1.6mm – 16mm |
| $\rho$ | Density | kg/m³ | 7850 (Steel) |
Practical Examples of RHS Weight Calculation
Example 1: Standard Structural Beam
A construction project requires 10 beams of RHS 150x50x4. The length of each beam is 6 meters. The material is standard mild steel.
- Inputs: 150mm (W), 50mm (H), 4mm (t), 6m (L), 10 Qty.
- Area Calculation: Outer Area = $150 \times 50 = 7500 mm^2$. Inner Area = $(150-8) \times (50-8) = 142 \times 42 = 5964 mm^2$.
- Net Area: $7500 – 5964 = 1536 mm^2$ ($0.001536 m^2$).
- Weight per Meter: $0.001536 \times 7850 = 12.06 kg/m$.
- Total Weight: $12.06 \times 6m \times 10 \text{ pcs} = 723.6 kg$.
Example 2: Aluminium Architectural Feature
An architect specifies an aluminium RHS 100x50x3 for a lightweight facade frame. Length is 3.5 meters.
- Inputs: 100mm (W), 50mm (H), 3mm (t), 3.5m (L), Aluminium Density (2700 kg/m³).
- Weight per Meter: Approx 2.33 kg/m.
- Total Weight: $2.33 \times 3.5 = 8.16 kg$.
- Financial Impact: Aluminium is lighter but often more expensive per kg than steel. Using the rhs steel weight calculator helps compare these material costs effectively.
How to Use This RHS Steel Weight Calculator
- Enter Dimensions: Input the outer Width (A) and Height (B) in millimeters.
- Specify Thickness: Enter the wall thickness (t) in millimeters. Ensure the thickness is less than half of the smallest dimension.
- Set Length & Quantity: Input the length per piece in meters and the total number of pieces required.
- Select Material: Choose the correct material density. The default is Mild Steel (7850 kg/m³), but options for Stainless Steel and Aluminium are available.
- Add Cost (Optional): For a financial estimate, input the current price per kilogram.
- Analyze Results: Review the total weight, weight per meter, and surface area for painting estimations.
Key Factors That Affect RHS Steel Weight Results
When using an rhs steel weight calculator, consider these six factors that influence the final figures:
1. Corner Radii
Real-world RHS is not perfectly sharp-cornered; it has rounded corners. This calculator uses a geometric box subtraction method. In reality, the rounded corners slightly reduce the mass compared to a sharp-cornered theoretical model. However, for most estimation purposes, the difference is negligible (< 1-2%).
2. Manufacturing Tolerances
Steel mills produce sections within specific tolerances (e.g., EN 10219 or AS 1163). Wall thickness can vary by +/- 5% to 10%. This means the actual weight of the steel delivered may differ slightly from the theoretical calculator result.
3. Galvanization
If the steel is hot-dip galvanized, zinc is added to the surface. This typically adds 3% to 5% to the total weight of the section, which must be accounted for in lifting plans.
4. Material Density Variations
While 7850 kg/m³ is the standard for mild steel, different grades (like weathering steel or high-tensile steel) may have minute density differences. Stainless steel is slightly heavier (approx 7900-8000 kg/m³).
5. Weld Seams
RHS is typically welded from a flat strip. The internal weld seam adds a small amount of material that is not accounted for in simple geometric formulas, though it is usually offset by the corner radii reduction.
6. Cost Fluctuations
The financial output of the calculator is highly sensitive to the "Price per kg" input. Steel prices fluctuate daily based on global supply chains, scrap metal prices, and energy costs.
Frequently Asked Questions (FAQ)
Yes, provided you select "Stainless Steel" from the material dropdown. Stainless steel is denser than mild steel, so using the correct density setting is crucial for accuracy.
Absolutely. The rhs steel weight calculator subtracts the inner void volume from the outer volume to calculate the net steel mass.
Surface area is vital for estimating the cost of secondary processes like painting, powder coating, or galvanizing, which are often charged by the square meter.
Yes. For SHS, simply enter the same value for both Width and Height inputs.
We use the industry standard of 7850 kg/m³ for mild steel. This is the value used in most engineering codes worldwide.
Enter the current market price in the "Material Cost per kg" field. The calculator will multiply the total weight by this rate to give an estimated total cost.
If the wall thickness is too large (i.e., $2 \times thickness \ge width$), the calculator will show an error because the inner void would theoretically disappear or overlap.
Yes, select "Aluminium" in the material list. The density will adjust to ~2700 kg/m³, resulting in a much lighter weight calculation compared to steel.
Related Tools and Internal Resources
Expand your engineering toolkit with our other specialized calculators:
- Square Hollow Section (SHS) Calculator – Calculate weights for square tubing.
- Circular Hollow Section (CHS) Calculator – For round pipes and tubes.
- Universal Beam (UB) Calculator – Estimate mass for I-beams and H-beams.
- General Metal Weight Calculator – For plates, bars, and custom shapes.
- Structural Steel Price Estimator – Advanced budgeting for construction projects.
- Engineering Unit Converter – Convert between metric and imperial units easily.