How metal weight is calculated
The calculator first determines the cross-sectional area of the chosen shape, whether that is a round bar, flat bar, square bar, tube, pipe, sheet, or plate. It then multiplies the area by the length to get the volume, and multiplies the volume by the alloy density to get the weight.
Each metal alloy has a characteristic density. Steel is approximately 7,850 kg per cubic metre, aluminium around 2,710, copper around 8,940, and brass around 8,500. Using the correct alloy density is important because the weight difference between materials of the same dimensions can be substantial.
Weight = Cross-section area x Length x Density
Multiply the cross-section area by the length to get volume, then multiply by the alloy density to get weight.