← Back to Bead BoardSteel rectangular tube weight calculator
Rectangular HSS — the other half of the hollow structural section family. Trailer frames, equipment guards, gate posts. 3" × 2" × 1/4" wall is 7.66 lb/ft. 4" × 2" × 1/4" is 9.36 lb/ft. Enter the outside dimensions and wall, get the weight.
Quick answer
Calculate rectangular HSS weight by width, height, and wall thickness.
Rectangular HSS weight per foot
Formula: (W × H − (W − 2t)(H − 2t)) × 12 × 0.2836 lb/in³. Same formula as square tube but with different width and height. ASTM A500 Grade B/C is the standard spec. Real HSS runs ±3% from nominal due to corner radius and wall tolerance.
Questions welders ask about this one
What is the difference between rectangular and square tube?
Just the shape — square tube has equal sides, rectangular tube has different width and height. Both are HSS (Hollow Structural Section) per ASTM A500. The weight formula is the same: outer area minus inner area times length times density. Rectangular tube is the better choice when you need stiffness in one direction more than the other.
What size rectangular tube for a trailer frame?
Most utility trailer frames use 3" × 2" or 4" × 2" rectangular tube with 3/16" or 1/4" wall. A 16-foot trailer main rail in 4" × 2" × 1/4" weighs about 150 lb per rail (9.36 lb/ft × 16 ft). Cross members are typically lighter — 2" × 1" or 3" × 1-1/2" at 0.120" wall.
Is rectangular HSS the same grade as square HSS?
Yes. Both are made to ASTM A500. Grade B (46 ksi yield) is the most common. Grade C (50 ksi yield) is specified when higher strength is needed. The density and weight per foot are identical across grades — the only difference is mechanical properties.
Weight is only half of material cost. To turn these pounds into a number you can quote, run the weld cost calculator for wire, gas, and labor per inch, or the job pricing calculator to build the whole bid.
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