Metal Weight Calculator
Metal is bought, sold, shipped and lifted by weight, so knowing the mass of a piece of stock before you cut, order or move it is one of the most useful calculations in any workshop or fabrication shop, and this calculator does it for the common shapes and materials in one place. Pick the material, choose the shape, plate or sheet, round bar, square bar, round tube or flat bar, enter the dimensions in millimetres, and it returns the weight in kilograms. The method behind it is simple and exact: it works out the volume of the piece from its geometry, then multiplies by the density of the metal you selected. Steel sits around 7,850 kilograms per cubic metre, stainless a little more, aluminium about a third of that at 2,700, with copper, brass, titanium and lead each carrying their own standard density, all built into the calculator so you do not have to look them up. That covers the great majority of everyday engineering and construction stock. Getting the weight right matters for real reasons. Metal suppliers price and quote by the kilogram or tonne, so an accurate figure feeds straight into a cost estimate. Weight determines whether a load is safe to lift by hand, with a hoist or on a vehicle, and whether a structure or rack can carry it. And in design it affects everything from freight to the loads a frame must support. This makes the tool genuinely useful for fabricators, engineers, builders, farmers and DIYers estimating jobs, ordering material, or planning a lift, as well as for students learning the link between volume, density and mass. The formula and a worked example are explained clearly below.
How it works
The calculator finds the volume from the shape: plate is length times width times thickness; round bar is pi over 4 times diameter squared times length; square bar is side squared times length; round tube is pi over 4 times outside diameter squared minus inside diameter squared, times length; flat bar is width times thickness times length. With dimensions in millimetres, the volume is scaled to cubic metres and multiplied by the material density to give the weight in kilograms.
Worked example
A steel round bar 25 mm in diameter and 1,000 mm long has a volume of pi over 4 times 25 squared times 1,000, about 490,874 cubic millimetres, which is 0.000491 cubic metres. Times the steel density of 7,850 gives about 3.85 kilograms.
Related calculators
- Rebar Weight Calculator: reinforcing steel.
- Volume Calculator: common solids.
- Density Calculator: mass, volume, density.
- Cylinder Volume Calculator: bar volume.
- Glass Weight Calculator: the same question for glass, acrylic and polycarbonate.