The calculation, without hidden assumptions
Estimate SHS/RHS and rectangular or square tube mass from outer-minus-inner cross-sectional area. MAXScanner keeps the sharp-corner theoretical model visible, supports metric and imperial measurements, and lets you compare a supplier kg/m value without pretending calculated geometry equals certified mill mass.
How to use this calculator
Enter outside width and height; use equal values for SHS or different values for RHS.
Enter nominal wall thickness and piece length, then choose dimensions/length units.
Keep 7,850 kg/m³ for typical carbon-steel screening or enter the documented density for another material.
Optionally enter rate/kg, a target mass for reverse whole-piece count, or supplier kg/m for variance checking.
Use the substituted steps to verify the inside dimensions and theoretical metal area.
Where people use it
- •Estimate RHS/SHS takeoff mass before requesting a supplier quote.
- •Compare kg/m with lb/ft on mixed-unit drawings or purchase documents.
- •Plan piece and batch mass for fabrication and transport screening.
- •Reverse an order/truck mass into whole equal-length sections.
- •Audit the difference between a sharp-corner estimate and a supplier or mill kg/m value.
100 × 50 × 5 mm RHS, 6 m × 2 pieces
The sharp-corner model gives 1,400 mm² metal area and 10.99 kg/m at 7,850 kg/m³. Each 6 m piece is about 65.94 kg; two pieces are about 131.88 kg. Real tabulated RHS can differ because formed corners are rounded.
What the result does not assume
- •Real cold-formed hollow sections have corner radii; the outer-minus-inner rectangular model is deliberately identified as a theoretical sharp-corner estimate.
- •Use the governing standard, certified section table or mill test certificate when nominal mass is contractually or structurally important.
- •Density varies by alloy; do not silently apply carbon-steel density to aluminum, stainless or another material.
- •This calculator estimates mass only. It does not calculate section modulus, buckling, capacity, weld design or member adequacy.
- •Coatings, galvanizing, weld upset and manufacturing tolerances can change delivered mass.
Frequently asked questions
How is rectangular hollow section weight calculated?+
Subtract the inner rectangle from the outer rectangle to get theoretical metal area, convert mm² to m², then multiply by material density for kg/m and by length for piece mass.
Does the same calculator work for SHS?+
Yes. Enter the same outside width and height for a square hollow section. The geometry then becomes a square outer section with a square inner void.
Why can supplier RHS weight differ from the result?+
Real cold-formed sections have rounded corners plus manufacturing tolerances and weld effects. Supplier and governing-standard tables should control when certified nominal mass matters.
What steel density is used?+
The default is 7,850 kg/m³ for common carbon-steel estimating. It is editable so another documented material density can be used explicitly.
Can I calculate how many sections fit in a target mass?+
Yes. Enter a target kg or lb value and MAXScanner reports the number of whole sections at the entered piece length that fit within that theoretical mass.
Can this result be used for structural design?+
No. Weight geometry does not establish strength, section properties, grade, local buckling limits or code compliance. Use certified section data and the governing design standard.
Semantic next steps
Continue the calculation
These links move to a different input, formula or project stage rather than a keyword variation of this page.
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Keep the result connected to the real job
MAXScanner keeps the formula and assumptions beside the result so you can verify the number before using it in a drawing, estimate, specification, worksheet or document. Where a supplier, manufacturer, drawing or applicable standard owns a requirement, that source remains authoritative.