Theoretical mass and weight
Tube weight calculator
Estimate cross-sectional area, weight per length, piece weight, and order weight. Results are theoretical and not acceptance criteria.
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Tube weight calculator
Round: area = π/4 × (OD² − ID²), ID = OD − 2 × wall. Square and rectangular use outer minus inner rectangles, which slightly overstates weight by ignoring corner radii. Steel density 0.2836 lb/in³ (7,850 kg/m³). Real weight varies with corners, weld upset, scale, coating, and dimensional tolerance — never accept or reject material on calculated weight alone.
Calculation method
The calculator subtracts the inner hollow area from the outer profile area, then multiplies by density and length. Corner radii, weld upset, tolerances, scale, coatings, and density variation can make measured weight differ.
For round tube: area = π/4 × (OD² − ID²), where ID = OD − 2×wall. For square and rectangular tube the outer and inner rectangles are used, which slightly overstates weight by ignoring corner radii. Steel density is taken as 0.2836 lb/in³ (7,850 kg/m³).
Interpretation limits
Theoretical weight is a planning number for freight, handling, and rough cost checks. It is not a conformance measurement: A513 product is ordered to dimensions, and dimensional tolerances mean actual weight varies piece to piece. Never accept or reject material on calculated weight alone.
If a shipment's measured weight differs meaningfully from the theoretical figure, treat that as a prompt to verify dimensions against the purchase order — wall thickness at several points around the circumference, outside dimension, and length — rather than as evidence of nonconformance by itself. Density also varies slightly by grade and by producer practice, so small deltas are expected and normal.