Physics & materials engineering
Quickly calculate the weight of steel plate, round bar, pipe, hollow and hexagon sections from dimensions — and look up the density of metals, stone, building materials, wood, plastics, liquids and gases.
m = ρ × V · 1 g/cm³ = 1000 kg/m³
Choose a steel type
Enter dimensions in mm. Choose a material or click a row in the table below.
Results are theoretical weights from nominal dimensions, excluding rolling tolerance, hollow-section corner radii and cutting loss.
Weight = density × volume. For carbon steel (ρ = 7850 kg/m³) with dimensions in mm, these quick formulas apply:
| Steel type | Formulas | Unit |
|---|---|---|
| Steel plate (thickness T) | 7.85 × T | kg/m² |
| Steel plate (L × W × T) | L × W × T × 7.85 / 10⁶ | kg |
| Round bar (D) | 0.006165 × D² | kg/m |
| Pipe (OD × t) | 0.02466 × (OD − t) × t | kg/m |
| Hollow section (A × B × t) | 0.0157 × t × (A + B − 2t) | kg/m |
| Square / rectangular bar (A × B) | 0.00785 × A × B | kg/m |
| Hexagon bar (S across flats) | 0.0068 × S² | kg/m |
For stainless 304 (7930 kg/m³) multiply the result by 1.01; for aluminium (2700 kg/m³) multiply by 0.344. The calculator above does this automatically when you choose a material.
0.006165 × 20² = 2.47 kg/m. A 6 m bar weighs about 14.8 kg.
7.85 × 10 = 78.5 kg/m². A 1500 × 6000 × 10 mm plate weighs 706.5 kg.
0.02466 × (114.3 − 6.02) × 6.02 ≈ 16.08 kg/m. A 6 m length weighs about 96.5 kg.
0.0157 × 4 × (100 + 50 − 8) ≈ 8.92 kg/m (theoretical, square corners). Real hollow sections have rounded corners, so they are slightly lighter.
Common carbon steel (SS400, A36, S235, S355) is taken as 7850 kg/m³ (7.85 g/cm³). Stainless 304 is about 7930 kg/m³, stainless 316 about 7980 kg/m³.
The result is the theoretical weight from nominal dimensions. Actual weight also depends on rolling tolerance (plate is usually slightly thicker than nominal), hollow-section corner radii and any galvanizing.