Why is the design thickness less than the nominal?

Because electric-resistance-welded HSS is produced to a wall thickness tolerance that runs consistently below nominal, and the design specification accounts for it by requiring 0.93 times nominal for capacity calculations. It is not a defect allowance — it is the recognised production reality. Weight, though, is conventionally taken on nominal, so the two calculations legitimately use different figures.

Does the corner radius affect the weight?

Yes, slightly, and the calculation here does not model it. A cold-formed HSS has rounded corners rather than square ones, which removes a small amount of material from each corner along the full length. On a heavy-walled small section it is a measurable fraction; on a thin-walled large one it is negligible.

Why does my delivered weight exceed the calculation?

Almost always fabrication. End plates, gussets, base plates, stiffeners and weld metal are not in a section-weight calculation and can add ten percent or more to a braced frame. Beyond that, mill tolerance on wall thickness produces a genuine spread, and fabricators frequently charge on stock length rather than cut length.

Is HSS the same as a pipe?

Not for specification purposes, even where the shape looks similar. HSS and structural pipe are made to different standards with different yield strengths, different tolerances and different designation systems — pipe is called out by nominal size and schedule, HSS by outside dimensions and wall. Substituting one for the other on a drawing is not a like-for-like swap.

HSS (Square/Rectangular Tube) Weight Calculator

Calculate a hollow structural section (HSS) tube's weight per unit length from its outer dimensions and wall thickness.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market

Imperial · sales tax

Outer Width (mm)

Outer Height (mm)

Wall Thickness (mm)

Weight per meter

17.71 kg/m

High confidence

Cross-sectional area: 2256 mm²

At the values currently entered, the weight per meter works out to 17.7 kg/m. Figures are shown for United States, where IRC 2024 is the governing residential reference; switch the market above if you are building elsewhere.

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This result is a specification — 17.71 kg/m — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

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Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

HSS cross-sectional area = outer area − inner area = (width × height) − ((width − 2×wall thickness) × (height − 2×wall thickness)); weight per unit length = area × steel density (7850 kg/m³)

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Frequently asked questions

Why is the design thickness less than the nominal?: Because electric-resistance-welded HSS is produced to a wall thickness tolerance that runs consistently below nominal, and the design specification accounts for it by requiring 0.93 times nominal for capacity calculations. It is not a defect allowance — it is the recognised production reality. Weight, though, is conventionally taken on nominal, so the two calculations legitimately use different figures.
Does the corner radius affect the weight?: Yes, slightly, and the calculation here does not model it. A cold-formed HSS has rounded corners rather than square ones, which removes a small amount of material from each corner along the full length. On a heavy-walled small section it is a measurable fraction; on a thin-walled large one it is negligible.
Why does my delivered weight exceed the calculation?: Almost always fabrication. End plates, gussets, base plates, stiffeners and weld metal are not in a section-weight calculation and can add ten percent or more to a braced frame. Beyond that, mill tolerance on wall thickness produces a genuine spread, and fabricators frequently charge on stock length rather than cut length.
Is HSS the same as a pipe?: Not for specification purposes, even where the shape looks similar. HSS and structural pipe are made to different standards with different yield strengths, different tolerances and different designation systems — pipe is called out by nominal size and schedule, HSS by outside dimensions and wall. Substituting one for the other on a drawing is not a like-for-like swap.