Metal Weight Calculator for Plate, Bar, and Tube
Estimate the mass of rectangular plate, solid round bar, or round tube from dimensions, density, and quantity. Enter dimensions in millimetres or inches. You can also change density to match the specific alloy or material certificate rather than relying on a generic default.
This tool calculates geometric volume and multiplies it by density. It does not identify a material from its name. If you use the default steel density, treat the answer as an estimate and verify the material grade and supplier data.
Interactive calculator
Enter values and select Calculate.
Formula and units
For a plate, volume is length × width × thickness. For round bar, volume is π × diameter² ÷ 4 × length. For round tube, subtract the inner cylinder from the outer cylinder: π × (outside diameter² − inside diameter²) ÷ 4 × length.
Mass is volume × density. When dimensions are in millimetres and density is in kilograms per cubic metre, the calculator converts cubic millimetres to cubic metres before calculating kilograms. Quantity multiplies the mass per piece to give total mass.
Worked example: steel plate
A plate that is 1,000 mm long, 500 mm wide, and 2 mm thick has a volume of 1,000,000 mm³, or 0.001 m³. At 7,850 kg/m³, its estimated mass is 7.85 kg. A quantity of eight plates has an estimated total mass of 62.8 kg.
The density value matters. A generic steel reference lists 7,850 kg/m³, but alloy composition and product condition can change density. Stainless grades, aluminium alloys, and cast materials need their own value. The Engineering ToolBox metal density reference is a starting reference, not a substitute for a material specification.
What this estimate excludes
The calculator assumes constant cross-sections and exact nominal dimensions. It does not subtract slots, pockets, chamfers, holes, bevels, or cutouts. It also excludes scale, coating, moisture, and dimensional tolerances. Use CAD mass properties or a weighed sample when shipping, lifting, or load calculations require a controlled value.
For round tube, enter the inside diameter smaller than the outside diameter. For plate, bar, and tube, make sure the selected shape matches the dimensions you enter. Compare related options with the sheet nesting calculator or browse the engineering calculator directory.
