HSS7x7x3/8 — Dimensions, Weight & Section Properties
Hollow structural section per ASTM A500 / AISC Steel Construction Manual
HSS7x7x3/8 is an American hollow structural section (HSS) 7×7 inches (177.8×177.8 mm) with a nominal 0.375 in wall, weighing 32.58 pounds per foot (48.5 kg/m). Section properties below are the AISC published values, computed with the A500 design wall thickness of 0.93×nominal — with metric equivalents alongside.
Typical uses: columns, braces, truss members, equipment frames, and architectural steel — closed sections excel in compression and torsion and take paint beautifully. For a quick stiffness check, see the deflection example below or open the beam calculator with your own span and load.
Dimensions
| Height h | 7 in (177.8 mm) |
| Width b | 7 in (177.8 mm) |
| Nominal wall t | 0.375 in (9.5 mm) |
| Design wall (0.93t) | 0.349 in (8.9 mm) |
Weight & Cross-Section
| Weight per foot | 32.58 lb/ft (48.5 kg/m) |
| 20 ft bar | 652 lb |
| 40 ft bar | 1,303 lb |
| Area A | 8.97 in² (57.9 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 65 in⁴ (2,705 cm⁴) |
| Section modulus Sx | 18.6 in³ (305 cm³) |
| Radius of gyration rx | 2.69 in |
| Moment of inertia Iy | 65 in⁴ (2,705 cm⁴) |
| Section modulus Sy | 18.6 in³ (305 cm³) |
| Radius of gyration ry | 2.69 in |
Compared with the neighbouring sizes
| Shape | h × b (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| HSS7x7x1/4 | 7 × 7 | 22.42 | 46.5 | 13.3 | −31 % | −28 % |
| HSS7x7x3/8 (this page) | 7 × 7 | 32.58 | 65 | 18.6 | — | — |
Deflection example
A simply supported HSS7x7x3/8 spanning 11 ft with a 10 kip point load at midspan deflects 0.25 in (E = 29,000 ksi, Ix = 65 in⁴). The L/360 serviceability limit for this span is 0.37 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a HSS7x7x3/8 tube weigh?
HSS7x7x3/8 weighs 32.58 pounds per foot (48.5 kg/m). A 20 ft bar weighs 652 lb and a 40 ft bar 1,303 lb.
What are the dimensions of a HSS7x7x3/8?
HSS7x7x3/8 is 7×7 in (177.8×177.8 mm) outside, with a nominal wall of 0.375 in. Note that A500 tolerances put the design wall at 0.93×nominal (0.349 in) — the section properties listed already account for this.
What are the dimensions of a HSS7x7x3/8 in mm?
HSS7x7x3/8 is 177.8×177.8 mm outside with a nominal wall of 9.5 mm. In metric section properties: Ix = 2,705 cm⁴, Sx = 305 cm³.
How much does a HSS7x7x3/8 weigh in kg?
48.5 kg per meter. A 6 m bar weighs 291 kg and a 12 m bar 582 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a HSS7x7x3/8?
About the strong axis, Ix = 65 in⁴ (2,705 cm⁴) with section modulus Sx = 18.6 in³. About the weak axis, Iy = 65 in⁴ and Sy = 18.6 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
HSS7x7x3/8 or HSS7x7x1/4 — what does one size down change?
HSS7x7x1/4 is about 31% lighter (22.42 vs 32.58 lb/ft) but about 28% less stiff (Ix 46.5 vs 65 in⁴). Check deflection before downsizing — stiffness falls much faster than weight.
Values are entered from the governing standard’s published tables and cross-checked programmatically against its mass and section formulas before publication. Spotted an error? Write to advertising@metalabout.net — verified corrections ship within days. About