Instant, accurate weight calculations for TMT bar, steel plate, MS pipe, angle, channel & beam. Pick a calculator below or use the all-in-one tool.
Steel weight calculators are specialised tools that compute the mass of steel sections based on their dimensions and material grade. Whether you are working with TMT rebar, mild steel plates, MS pipes, structural angles, channels or I-beams, these calculators apply the correct engineering formula so you get an accurate weight in kilograms or tonnes — instantly.
In construction and fabrication, steel is bought and sold by weight. A contractor estimating a residential slab needs to know the total TMT rebar weight to generate a Bill of Quantities. A fabricator cutting steel plates for a tank must calculate plate weight to verify the supplier's invoice. A structural engineer sizing an I-beam needs section weight to check dead-load assumptions.
Each section shape has its own formula. Round bars and TMT rebars use the well-known d²/162 shortcut. Plates use Length × Width × Thickness × 7.85 (dimensions in mm, result in kg). Pipes use (OD − WT) × WT × 0.02466. All of these formulas derive from the base density of mild steel: 7,850 kg/m³.
SteelMath's calculators handle the maths for you. Just select a section type, enter your dimensions, and get the result. We support multiple material grades — MS, Fe500, SS 304, SS 316, Aluminium and Copper — with automatic density correction. Results can be shared via WhatsApp, downloaded or printed.
Steel weight is calculated by multiplying the cross-sectional area of the section by its length and the density of steel (7,850 kg/m³). Different section shapes — round bar, plate, pipe, angle — each have their own simplified formula. SteelMath provides free calculators for every common section type.
The d²/162 formula is a shortcut to find the weight per metre of round steel bars and TMT rebars. You square the diameter in mm and divide by 162.2. For example, a 12 mm TMT bar weighs 12² ÷ 162.2 = 0.889 kg/m. The constant 162.2 comes from simplifying the full formula: (π/4) × d² × 7850 / 1,000,000.
Mild steel (MS) and TMT rebar have a density of 7,850 kg/m³ (7.85 g/cm³). Stainless steel SS 304 is slightly heavier at 8,000 kg/m³, and SS 316 is 8,027 kg/m³. Aluminium is much lighter at 2,700 kg/m³. SteelMath calculators automatically apply the correct density for the selected grade.
Accurate weight calculation is critical for estimating material costs, verifying supplier invoices, designing structural members, and planning transport logistics. Steel is typically purchased by weight (per kg or per tonne), so even small errors in calculation can lead to significant cost differences on large projects.