Sheet Metal Weight Calculator

The weight of a sheet is its volume multiplied by its density. If you write the thickness in millimetres and the width and length in metres, the formula becomes simple:

• Weight (kg) = Thickness (mm) × Width (m) × Length (m) × Density (g/cm³)

Example: a 2 mm cold-rolled steel sheet measuring 1000 × 2000 mm = 2 × 1 × 2 × 7.85 = 31.4 kg. An aluminium sheet of the same size weighs 2 × 1 × 2 × 2.70 = 10.8 kg.

The weight of a coil comes from the volume of the ring between its outer and inner diameter. Dimensions are taken in metres and density in kg/m³ (7850 for steel):

• Weight (kg) = 3.1416 ÷ 4 × (Outer diameter² − Inner diameter²) × Width × Density
• Coil length = 3.1416 × (Outer diameter² − Inner diameter²) ÷ (4 × Thickness)

Example: a steel coil with an outer diameter of 1200 mm, an inner diameter of 508 mm and a width of 1000 mm weighs about 7,287 kg. If the sheet is 1 mm thick, the coil holds about 928 metres of sheet.

If you know the coil length, the calculation works the other way round: the weight is thickness × width × length × density, as for a sheet, and the outer diameter is calculated from that length.

An uncoiler is the machine that feeds coiled sheet into a production line. Four dimensions are enough to choose the right model:

• Coil weight: the heaviest coil the machine can carry
• Coil width: the widest coil that fits on the mandrel
• Outer diameter: the largest coil the arms and frame can take
• Inner diameter: the range the mandrel can clamp inside the coil

The calculator above suggests the smallest capacity that meets all four. For coils of 4,500 kg and above, a hydraulic coil loading car is recommended to place the coil safely on the mandrel.