Steel Weight Calculator Guide: Bars, Sheets & Structural Sections
Estimating steel weight is essential for construction cost planning, structural calculations, and logistics. Here are the formulas for common steel shapes.
Steel Weight Formulas
Flat Bar / Sheet
Round Bar
Hollow Pipe
Common Steel Densities
| Steel Type | Density (kg/m³) |
|---|---|
| Carbon/Mild steel | 7,850 |
| Stainless steel (304) | 8,000 |
| Stainless steel (316) | 7,990 |
| Cast iron | 7,200 |
| Wrought iron | 7,750 |
Frequently Asked Questions
What is the density of steel?
Carbon steel density is approximately 7,850 kg/m³ (7.85 g/cm³). Stainless steel is slightly heavier at 7,900–8,000 kg/m³. This density is what the weight formula is based on.
How do I calculate the weight of a steel flat bar?
Weight = Length (m) × Width (m) × Thickness (m) × 7,850 kg/m³. For example, a 3m × 50mm × 10mm flat bar: 3 × 0.05 × 0.01 × 7,850 = 11.775 kg.
How do I calculate the weight of a steel round bar?
Weight = π/4 × D² × L × 7,850 (where D = diameter in metres, L = length in metres). Simplified formula: Weight (kg) = D² (mm) × L (m) × 0.00617. Example: 20mm diameter × 6m long = 400 × 6 × 0.00617 = 14.81 kg.
How do I calculate steel sheet weight?
Weight = Length × Width × Thickness × 7,850. For a 2m × 1m × 5mm steel sheet: 2 × 1 × 0.005 × 7,850 = 78.5 kg. For a quick rule: a 1m × 1m × 1mm steel sheet weighs 7.85 kg.
What is the difference between MS and SS steel?
MS (Mild Steel / Carbon Steel) is iron with 0.05–0.25% carbon — strong, cheap, and commonly used in construction. SS (Stainless Steel) has 10.5%+ chromium, making it corrosion-resistant but 3–5x more expensive. Both have similar density (~7,850 kg/m³).
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