Work out steel plate weight instantly with clear inputs, formula shown and shareable results.
Plate weight is volume times density. Working in millimetres, area in square metres is length times width divided by a million, and multiplying by thickness in metres gives volume. For mild steel at 7850 kg/m³ this reduces to the useful shortcut that each millimetre of thickness weighs 7.85 kg per square metre.
Plate weight
kg = length m x width m x thickness m x density
Shortcut
Mild steel: kg/m² = 7.85 x thickness in mm
kg = length m x width m x thickness m x density. Plate weight is volume times density.
Actual, if you have it. Hot rolled plate is permitted a minus tolerance, so on large orders the delivered weight can be a percent or two under the nominal calculation.
This calculator takes 4 inputs: Plate length, Plate width, Plate thickness, Material density. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.