RSJ Weight Calculator
Calculate the total mass and estimated cost of Rolled Steel Joists (RSJs) for construction and engineering projects.
102 x 44 x 7 kg/m
127 x 76 x 13 kg/m
152 x 89 x 16 kg/m
178 x 102 x 19 kg/m
203 x 102 x 23 kg/m
203 x 133 x 25 kg/m
203 x 133 x 30 kg/m
254 x 146 x 31 kg/m
254 x 146 x 37 kg/m
254 x 146 x 43 kg/m
305 x 102 x 33 kg/m
305 x 165 x 40 kg/m
406 x 178 x 67 kg/m
Standard Universal Beam sizes listed by Height x Width x Mass/m.
Enter the total length required in meters.
Please enter a valid positive length.
Total number of identical beams required.
Quantity must be at least 1.
Optional: Enter current market rate (e.g., $1200) to estimate material cost.
Price cannot be negative.
Total RSJ Weight
80.5 kg
Total Weight (Tonnes)
0.081 t
Estimated Material Cost
$96.60
Linear Mass Selected
23 kg/m
Formula Used: Total Weight = (Mass per Meter × Length) × Quantity.
Note: RSJ weights are theoretical nominal weights based on standard density (approx. 7850 kg/m³).
Note: RSJ weights are theoretical nominal weights based on standard density (approx. 7850 kg/m³).
Weight Breakdown & Comparison
| Parameter | Value |
|---|---|
| Profile Specification | 203 x 102 x 23 |
| Length per Beam | 3.5 m |
| Weight per Beam | 80.5 kg |
| Total Quantity | 1 |
| Total Load | 80.5 kg |
Selected Profile
Next Size Up (Comparison)
Chart 1: Cumulative weight comparison over length between selected profile and a heavier alternative.
What is an RSJ Weight Calculator?
An rsj weight calculator is a specialized engineering tool designed to compute the total mass of Rolled Steel Joists (RSJs), commonly known as I-beams or H-beams, based on their specific profile dimensions and length. These structural elements are the backbone of modern construction, used to support heavy loads over long spans.
Architects, structural engineers, builders, and steel fabricators use this calculator to estimate the dead load a beam adds to a structure and to calculate material costs accurately. Unlike generic volume calculators, an RSJ weight calculator uses standardized "mass per meter" data specific to Universal Beam (UB) classifications.
Common Misconception: Many people assume all steel beams of similar height weigh the same. However, the thickness of the web and flanges significantly alters the weight. A 203mm deep beam can range from 23kg/m to over 60kg/m depending on its classification.
RSJ Weight Calculator Formula and Explanation
Calculating the weight of a Rolled Steel Joist is relatively straightforward once the specific profile data is known. The calculation relies on the linear mass density of the steel profile.
The Formula
Total Weight (kg) = Linear Mass (kg/m) × Length (m) × Quantity
Variables Explanation
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| Linear Mass | Weight of the beam per meter of length | kg/m | 7 kg/m – 200+ kg/m |
| Length | The physical length of the steel beam | Meters (m) | 0.5m – 15m |
| Quantity | Number of identical beams | Count | 1 – 100+ |
| Total Weight | Combined mass of the order | kg or Tonnes | Varies |
Practical Examples of RSJ Weight Calculation
Example 1: Residential Extension Lintels
A builder needs two steel beams to support a new extension. The structural engineer specifies a 152 x 89 x 16 UB. The opening requires beams that are 4.2 meters long.
- Profile: 152 x 89 x 16 (Mass = 16 kg/m)
- Length: 4.2 m
- Quantity: 2
- Calculation: 16 kg/m × 4.2 m × 2 = 134.4 kg
Financial Interpretation: At a steel price of $1200/tonne ($1.20/kg), the raw steel cost is approximately $161.28.
Example 2: Commercial Warehouse Span
A commercial project requires a heavy-duty beam spanning 8 meters. The selected profile is a 406 x 178 x 67 UB.
- Profile: 406 x 178 x 67 (Mass = 67 kg/m)
- Length: 8.0 m
- Quantity: 1
- Calculation: 67 kg/m × 8.0 m = 536 kg (0.536 Tonnes)
Logistics Note: A 536kg beam cannot be lifted manually; this calculation confirms the need for mechanical lifting equipment like a crane or Genie lift.
How to Use This RSJ Weight Calculator
- Select Profile: Choose your beam size from the dropdown menu. The format "Height x Width x Weight" helps you identify the correct beam found in your structural drawings.
- Enter Length: Input the required length in meters. If your measurements are in millimeters, divide by 1000 (e.g., 3500mm = 3.5m).
- Set Quantity: If you are ordering multiple identical beams, increase the quantity field.
- Input Price (Optional): To get an estimated material cost, enter the current price of structural steel per tonne.
- Review Results: The calculator immediately displays total weight in kilograms and tonnes, along with a cost estimate.
Key Factors That Affect RSJ Weight Results
When using an rsj weight calculator for planning and budgeting, consider these six critical factors:
- Web & Flange Thickness: Two beams can have the same outer dimensions (e.g., 203 x 133) but different weights (25kg/m vs 30kg/m) due to the thickness of the steel. Always check the third number in the profile code.
- Steel Density: Standard structural steel has a density of approximately 7850 kg/m³. This calculator assumes standard carbon steel density.
- Manufacturing Tolerances: Hot rolled steel has manufacturing tolerances. Actual weight can vary slightly (±2.5%) from the theoretical nominal weight shown in tables.
- Coatings & Finish: The calculated weight is for "black steel." Galvanizing, painting, or fire-proof coatings add additional weight (usually 3-5%) not accounted for in standard mass tables.
- Fabrication Additions: End plates, welded cleats, and connection holes change the final weight. This calculator provides the raw beam weight only.
- Steel Market Volatility: The "Estimated Cost" is highly sensitive to global steel prices, which fluctuate based on supply chain demand, energy costs, and scrap metal availability.
Frequently Asked Questions (FAQ)
Does this calculator include the weight of end plates?
No. The rsj weight calculator computes the mass of the raw beam section only. Welded connections, plates, and bolts must be calculated separately by your fabricator.
What does "UB" mean in the dropdown menu?
UB stands for "Universal Beam," which is the standard term for I-shaped sections used in the UK and Australia. In the US, these are similar to Wide Flange (W) beams.
How do I convert millimeters to meters for the input?
Divide your millimeter measurement by 1000. For example, if your beam is 4200mm long, enter 4.2 into the length field.
Why is the weight important for my project?
Knowing the weight is critical for two reasons: Structural Load (the building must support the beam's weight) and Logistics (knowing if you need a crane or can lift it manually).
Can I calculate the weight of HEB or IPE beams here?
While this calculator lists standard Universal Beams, the logic applies to any beam if you know the mass per meter. You can estimate close matches, but for precise HEB/IPE data, ensure you select a profile with matching linear mass.
Is the calculated cost the final price I will pay?
No. The cost shown is for raw material only. It does not include cutting, delivery, VAT/tax, priming, or fabrication labor charges.
What is the heaviest RSJ available?
Universal Beams can go up to very heavy profiles, such as 914 x 419 x 388 kg/m, used in skyscrapers and bridges. This calculator focuses on sizes common in residential and light commercial projects.
How accurate is the weight calculation?
The calculation is mathematically precise based on nominal standards (BS 4-1 / EN 10025). However, real-world rolling tolerances mean the physical beam might vary slightly.
Related Tools and Internal Resources
Expand your construction financial planning with our other specialized tools:
- Steel Beam Span Calculator – Determine the maximum safe span for different beam sizes.
- Construction Cost Estimator – Comprehensive budgeting for extensions and renovations.
- Concrete Volume Calculator – Calculate cubic meters required for foundations and pads.
- Renovation Loan Calculator – Estimate monthly repayments for home improvement financing.
- Guide to Structural Steel Grades – Understand the difference between S275 and S355 steel.
- Crane Hire Cost Calculator – Estimate lifting costs based on beam weight and reach.