Steel Weight Calculator

Calculate the weight of any steel section — flat bar, round bar, square bar, RHS, SHS, angle, channel or I-beam. Get weight in kilograms instantly for any length. Metric and imperial.

Quick answer: Steel density = 7,850 kg/m³. A 50×50×3mm SHS, 6m long weighs: Area = (50×50 − 44×44) × 10⁻⁶ = 0.000636 m². Volume = 0.000636 × 6 = 0.003816 m³. Weight = 0.003816 × 7850 = 30.0 kg.

🔨 Steel Weight Calculator

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📐 How It Works

Steel weight is calculated from the cross-sectional area of the section multiplied by the length and steel density (7,850 kg/m³). Each section type has a different formula for cross-sectional area. Hollow sections subtract the hollow interior area from the outer area.

Weight = Cross-Section Area × Length × 7,850 kg/m³ Flat: Area = Width × Thickness Round: Area = π × (D÷2)² RHS/SHS: Area = Outer Area − Inner Area

📋 Worked Example

RHS 100×50×4mm, 6m long: Outer = 100×50 = 5,000 mm². Inner = 92×42 = 3,864 mm². Area = 1,136 mm² = 0.001136 m². Weight = 0.001136 × 6 × 7,850 = 53.5 kg per piece.

❓ Frequently Asked Questions

Structural steel density is 7,850 kg/m³ (7.85 g/cm³ or 490 lb/ft³). This applies to all common structural steel grades — mild steel (Grade 250), high strength (Grade 350), stainless steel is slightly denser at 7,900–8,000 kg/m³.

RHS = Rectangular Hollow Section. SHS = Square Hollow Section. Both are hollow steel tubes used for structural framing, posts, beams and fabrication. Dimensions are expressed as Depth × Width × Wall Thickness in mm, e.g. 100×50×4 RHS.

Divide kilograms by 1,000 to get metric tonnes. Steel is typically priced and sold by the tonne. 1 tonne = 1,000 kg. For ordering, round up to the nearest standard length (6m, 8m, 9m, 12m).

Structural steel in Australia is typically stocked in 6m, 9m and 12m lengths. Some sections are available in 7.5m and other lengths. Minimum cut charges apply for short lengths. Order in full lengths where possible to minimise waste and cutting charges.