Stainless steel square tube weight
Per-metre and total weight of a square tube from (side − wall) × wall × coefficient: side and wall in mm, length in m, density defaulting to 7.93 (304), with the coefficient and estimated inner/outer surface area, and hard errors on invalid sizes.
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Weight result
Approximate formula — weigh for invoicing.
Enter the side to calculate the tube weight
Per metre: 0 · Total: 0 · Side: 0
What this tool does
- Estimate material for railings, racks or canopies: length × per-metre weight gives the total for freight brackets.
- Check a supplier's weight table by swapping the handbook 0.0314 coefficient for a 7.93 density.
- Plan lifting and transport: get the total weight before picking clamps or a forklift.
Example
Input
50
Output
边长 50 mm、壁厚 2 mm 的方管每米重量：3.04512 kg/m 6 m 总重量：18.27072 kg 系数 4 × 7.93 ÷ 1000：0.03172 截面外接方形周长：0.2 m 每米表面积（内外表面估算）：0.384 m²/m 公式：(边长 50 − 壁厚 2) × 壁厚 2 × 系数 0.03172 × 长度 6 = 18.27072 kg
A 40 × 40 × 1 mm 304 tube is about 1.237 kg per metre; switch the density to 7.85 to reproduce the 0.0314 carbon-steel coefficient from steel handbooks.
Frequently asked questions
Where does 0.0314 come from?
0.0314 = 4 × 7.85 ÷ 1000 — the four walls flattened into plates at the carbon-steel density of 7.85 g/cm³, so (side − wall) × wall × 0.0314 yields kg/m directly. Stainless 304 uses 7.93, giving 0.0317; just change the density field.
Why is it approximate?
The formula treats the walls as flat plates on the outer square and ignores the corner radii (typically 1–3 × wall), so it reads a little low versus an exact developed-length calculation — usually within 1%–3%. Weigh for invoicing.
How do I fill in the fields?
Side in millimetres (40 or 40x40 — unequal sides are rejected as a rectangular tube), wall thickness in millimetres, and length in metres, defaulting to 1 m.
Can it handle rectangular tube?
No, this tool is for square sections only. For rectangular tube use the industry form (long + wide − 2 × wall) × wall × coefficient.
What is the surface area for?
Paint, galvanising and polishing budgets depend on area. The number is the per-metre outer plus inner surface (4a + 4(a − 2t)), excluding the end faces.
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