Free tool · Reference
Steel Weight Calculator
Work out the weight of UK steel beams, columns, channels, angles and hollow sections, plus plate and flat bar. Add your own rate per tonne for a rough material cost.
Quick answer
Steel weight = mass per metre × length × quantity. For example, a 203 × 133 × 25 UB is 25.1 kg/m, so four 6 m lengths weigh 602.4 kg. For plate or flat bar, weight = length × width × thickness × 7,850 kg/m³. Add your own rate per tonne to see a material cost.
Cite this: Koyda Ltd, “Steel Weight Calculator”, https://www.koyda.com/steel-weight-calculator/, reviewed 10 October 2026.
Calculator
Steel weight calculator
Pick a section and size, enter the length and quantity, and get the total weight. Plate and flat bar are worked out from their dimensions at 7,850 kg/m³.
- Section weight = mass per metre × length × quantity
- Plate or flat bar weight = length × width × thickness × 7,850 kg/m³ × quantity
A 305 × 165 × 40 UB is 40.3 kg/m, so four 6 m lengths weigh 40.3 × 6 × 4 = 967.2 kg. A 10 mm plate 1,000 × 500 mm weighs 1.0 × 0.5 × 0.01 × 7,850 = 39.25 kg. Weights are nominal and exclude coatings, plates and fittings.
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Pricing a whole job? Steel Quote Builder
List every beam, column, angle and box section with its cut length, get the total weight, a cutting plan into stock lengths with the offcuts, and a supplier enquiry or customer quotation as a PDF.
More free tools: beam span and load checker · lintel and padstone helper · paint and galvanising area calculator · delivery and lifting check
Use the tables and calculator offline
Install the Koyda app: section tables, weight calculator, CSV and PDF downloads, even without signal on site.
Section tables
Full dimensions and properties
The calculator uses the mass per metre from our steel section tables. Each table has dimensions, area, I and W, a diagram and a CSV download.
Questions
Frequently asked questions
How do I calculate the weight of a steel beam?
Multiply the mass per metre by the length and the number of pieces. A 203 × 133 × 25 UB is 25.1 kg/m, so four 6 m lengths weigh 25.1 × 6 × 4 = 602.4 kg.
How do I calculate the weight of steel plate?
Multiply length × width × thickness in metres by the density of steel, 7,850 kg/m³. A 1,000 × 500 × 10 mm plate weighs 1.0 × 0.5 × 0.01 × 7,850 = 39.25 kg.
Is the cost a quote?
No. The cost is your rate per tonne multiplied by the weight. It covers material only, not cutting, fabrication, finishes, delivery or VAT. Send your drawings for a fabricated price.
Reference only
Reference only. Values are nominal figures for the standard UK section ranges. Check them against current manufacturer data, and have a structural engineer confirm sizes before you use them in design. Koyda Ltd accepts no liability for decisions based on these tables.
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