Metal Weight Calculator
Pick a shape, enter the dimensions in millimetres or inches, choose the grade. The weight comes from the section geometry and the grade density, in the same engine that prices the enquiry.
Sheet / plate
What this calculates
Eight shapes run through this one page: sheet and plate, round, square, flat and hex bar, pipe and circular tube, rectangular and square hollow section, and equal angle. Each has its own formula in the calculation engine; the page only routes your inputs to it and prints the answer.
Density comes from the grade table, and the line under the grade says which value was used. Choose a named grade and you get that grade's figure; choose a generic family entry and you get a family typical value, close enough to size a load, not enough to price it — the exact grade decides the quoted weight.
Two readouts appear: the weight of the piece, and the weight per metre (per square metre for sheet). Both are theoretical: nominal dimensions, no rolling tolerance, no mill over-rolling. The quotation confirms the figure that goes on the order.
Show the formula and a worked example
The formula
- sheet / plate: W = L × W × t × ρ ÷ 10⁹
- round bar: W = π × (D ÷ 2)² × L × ρ ÷ 10⁹
- square bar: W = s² × L × ρ ÷ 10⁹
- flat bar: W = w × t × L × ρ ÷ 10⁹
- hex bar: W = (√3 ÷ 2) × AF² × L × ρ ÷ 10⁹
- pipe / tube: W = π ÷ 4 × (OD² − (OD − 2t)²) × L × ρ ÷ 10⁹
- RHS / SHS: W = (B × H − (B − 2t) × (H − 2t)) × L × ρ ÷ 10⁹
- equal angle: W = (2 × leg − t) × t × L × ρ ÷ 10⁹
Dimensions in millimetres, density ρ in kg/m³ — as the engine runs them.
Every shape reduces to cross-sectional area × length × density. Dimensions are in millimetres and density in kg/m³, so the product is divided by 10⁹ to land in kilograms; the per-metre readout is the same calculation run at a one-metre length.
For the hollow shapes the area is the outer section minus the bore: a pipe subtracts the inner circle, a hollow section subtracts the inner rectangle. The engine refuses a wall thickness that would leave no bore rather than printing a meaningless figure.
The hollow-section and angle areas ignore corner radii. The mill's section table gives the catalogue weight for a standard size; the difference is usually within a few percent, and it is the catalogue figure that goes on a quotation for a standard section.
Worked example
| Shape | Round bar |
|---|---|
| Diameter | 50 mm |
| Length | 6000 mm |
| Material grade | ASTM A36 |
| Density | 7,850 kg/m³ · grade density |
| Theoretical weight | 92.48 kg |
| Per metre | 15.41 kg/m |
Computed by the calculation engine from these inputs at render time, rounded only for display.
Frequently asked
- 01Why does the result differ from the mill certificate?
- The calculator uses nominal dimensions and the grade's reference density. A real bar or plate is rolled to a tolerance and the mill weighs what it made. Expect the certificate to sit a little above or below this figure; the quotation carries the certificate weight.
- 02Which density does the calculator use?
- The value in the grade table for the grade you chose. If you pick a generic family entry instead of a named grade, the line under the grade says "family typical value" so you know a confirmed grade may move the number.
- 03Can I enter dimensions in inches or the length in metres?
- Inches, yes — switch the entry units above the fields and every dimension is read in inches, converted to millimetres before the engine runs, and the enquiry carries the millimetre figures. Metres, no: length stays in millimetres so the number matches the mill order — a 6 m bar is 6000.
- 04What happens when I click "Get this quoted"?
- The enquiry form opens with the shape, dimensions, grade, density and computed weight already written into the requirement. Nothing is sent until you submit the form, and you can edit every line before you do.