⚖️ Steel Weight Calculator
Calculate the weight of steel sections by entering dimensions and length. Supports round bar, square bar, flat bar/plate, hexagonal bar, and angle iron. Results in kg, kg/m, and lbs.
Section Area Formulas
All dimensions in mm. Weight (kg) = A (mm²) × L (m) × ρ (kg/m³) / 1,000,000
Frequently Asked Questions
This calculator uses 7850 kg/m³ — the standard density for mild (carbon) structural steel (IS 2062, ASTM A36, S275/S355). High-strength alloy steels may vary slightly, but 7850 kg/m³ is universally accepted for structural calculations.
Mild steel has a density of 7850 kg/m³. Austenitic stainless steel (304, 316) is slightly denser at 7930–8000 kg/m³. Ferritic stainless steel is around 7750 kg/m³. For most practical engineering, the difference is less than 2% and mild steel density is commonly used as an approximation.
A quick rule of thumb for mild steel round bars: Weight (kg/m) ≈ D² / 162.2, where D is the diameter in mm. For example, a 20 mm round bar weighs about 400 / 162.2 ≈ 2.47 kg/m. This shortcut is derived from the full formula and is widely used in construction.
TMT (Thermo-Mechanically Treated) bars are reinforcement bars used in concrete structures. They are round bars with surface ribs. Their weight is calculated the same way as plain round bars using nominal diameter. Common sizes are 8, 10, 12, 16, 20, 25 and 32 mm.
A 1m × 1m steel plate weighs: Thickness (mm) × 7.85 kg. For example, a 10 mm thick steel plate weighs 10 × 7.85 = 78.5 kg per square metre. This is a handy rule: 1 mm thickness of steel weighs 7.85 kg/m².
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