Inputs
Profile shape (round bar, tube, square bar, flat bar, hexagon bar, sheet), the material or a custom density, the cross-sectional dimensions belonging to that shape, the length and the number of pieces.
Manufacturing · Semi-finished products
Metal weight of semi-finished products
Calculate the weight of a semi-finished product from shape, material and dimensions: m = ρ · A · L. Besides the total weight the calculator gives the weight per metre for checking against a merchant's table, the cross-sectional area, and the surface area used as the reference quantity for painting or galvanising.
Ideal geometry without dimensional tolerances, corner radii, mill scale or coating. Densities are nominal values for the alloy family per EN 1993-1-1 (steel), EN 1999-1-1 (aluminium) and EN 10088-1 (stainless steels); a custom density can be entered at any time.
mρ · A · L
02
Weight
Set the shape, material and dimensions.
Inputs and method
Metal weight of semi-finished products
Calculate the weight, weight per metre and surface area of a stock item from its shape, material and dimensions.
Calculation
The basis is m = ρ · A · L. The cross-sectional area A follows from the shape chosen: πd²/4 for round bar, π/4·(d²−(d−2t)²) for tube, a·b for flat bar and (√3/2)·AF² for hexagon bar from the across-flats size. A and ρ give the weight per metre; perimeter and length give the outer surface area.
Example
A 48.3 × 3.2 mm steel round tube has A = 453.4 mm² and therefore 3.559 kg/m; four 6 m lengths weigh 85.4 kg.
Sources and limits: m = ρ · A · L with ideal geometry. Densities as nominal values for the alloy family: 7,850 kg/m³ for steel per EN 1993-1-1, 2,700 kg/m³ for aluminium per EN 1999-1-1 and the EN 10088-1 values for stainless steels. Dimensional tolerances, corner radii of hollow sections, mill scale and coatings are excluded.
Metal weight of semi-finished products in detail
Calculate the weight, weight per metre and surface area of a stock item from its shape, material and dimensions.
What determines the weight of a stock item?
Semi-finished products are stock materials with a constant cross-section – bars, tubes, flats and sheets. Because their cross-section does not change along the length, their mass follows directly from three quantities: cross-sectional area, length and material density. The weight per metre combines the first two into exactly the number the steel trade works with.
Formula and variables
m = ρ · A · L
Round bar: A = π·d²/4Round tube: A = π/4 · (d² − (d − 2t)²)Square / flat: A = a² or A = b·hHollow section: A = b·h − (b − 2t)·(h − 2t)Hexagon from across-flats: A = (√3/2) · AF²
| Symbol / input | Meaning |
|---|---|
| ρ | Density of the material; the only material influence in this calculation. |
| A | Cross-sectional area, already net of the cavity for hollow sections. |
| L, n | Length of the single piece and number of identical pieces. |
| m/L | Weight per metre – the value found in steel trade weight tables. |
Choose the inputs correctly
Profile shape (round bar, tube, square bar, flat bar, hexagon bar, sheet), the material or a custom density, the cross-sectional dimensions belonging to that shape, the length and the number of pieces.
How to use the calculator
Choose the profile shape first – the form then asks for exactly the dimensions that shape has, including a wall thickness for hollow sections. Then choose the material (or enter your own density), enter the cross-sectional dimensions and the length in millimetres, and set the number of pieces. As a check, compare the reported weight per metre against your merchant's weight table.
Worked example
A 48.3 × 3.2 mm steel round tube has A = 453.4 mm² and therefore 3.559 kg/m; four 6 m lengths weigh 85.4 kg.
Which value is the right one for what?
The total weight is the number for ordering, transport and lifting gear. The weight per metre is the number for checking: it appears in every merchant's table and exposes a wrong shape or dimension immediately. The cross-sectional area, in turn, is precisely the quantity a subsequent tensile, compressive or stress calculation needs.
All dimensions in millimetres, density in kg/m³, result in kilograms. Watch the factor of 1,000 between g/cm³ (or kg/dm³) and kg/m³: steel is 7.85 g/cm³ and therefore 7,850 kg/m³.
Typical applications
Ordering material and costing by weight, transport and crane planning, estimating the galvanising or painting area, checking a CAD mass calculation, and converting between traded weight and required length.
Assumptions, limits and common mistakes
m = ρ · A · L with ideal geometry. Densities as nominal values for the alloy family: 7,850 kg/m³ for steel per EN 1993-1-1, 2,700 kg/m³ for aluminium per EN 1999-1-1 and the EN 10088-1 values for stainless steels. Dimensional tolerances, corner radii of hollow sections, mill scale and coatings are excluded.
Common mistake: For tubes and hollow sections do not enter the inside dimension – they are always designated by outside dimension and wall thickness. For hexagon bar the across-flats size is meant, not the corner-to-corner diagonal, which is larger by a factor of 1.155. And do not confuse mass with weight force: for slings and lifting gear the result still has to be multiplied by about 9.81 m/s² to get newtons.
Frequently asked questions
Why does the result differ slightly from the merchant's table?
For solid sections it practically never does – for hollow sections it does systematically: the calculator assumes sharp corners, while hot- or cold-formed hollow sections have corner radii. The tabulated weight is therefore usually one to three per cent below this ideal value, with wall thickness tolerances adding to that.
Which density should I use for stainless steel?
It depends on the microstructure: austenitic grades such as 1.4301 are 7,900 kg/m³, molybdenum-alloyed ones such as 1.4401/1.4571 are 8,000, ferritic ones such as 1.4016 are 7,700 and duplex 1.4462 is 7,800. These EN 10088-1 values are already offered in the material list.
What does the surface area tell me?
It is the outer surface of one piece, made up of the lateral surface plus both end faces, and therefore the quantity galvanisers and paint shops bill by. The bore surface of tubes is deliberately excluded, because normally only the outside is coated.
What is the length per tonne for?
Semi-finished products are often traded by weight but needed by length. The value states directly how many metres of this profile make up one tonne, making offers in €/t and in €/m comparable.
Does this also apply to beams such as IPE or HEB?
No. Rolled sections have root radii and tapered flange faces that do not follow from a few outside dimensions; their weight per metre is listed in the section tables of the relevant standard. This calculator covers the geometrically unambiguous stock shapes: round bar, tube, square, flat, hexagon and sheet.