HSS3x3x3/8 — Dimensions, Weight & Section Properties
Hollow structural section per ASTM A500 / AISC Steel Construction Manual
HSS3x3x3/8 is an American hollow structural section (HSS) 3×3 inches (76.2×76.2 mm) with a nominal 0.375 in wall, weighing 12.17 pounds per foot (18.1 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.
HSS3x3x3/8: cross-section drawn to scale from the AISC dimensions (3 × 3 × 0.375 in)Dimensions
| Height h | 3 in (76.2 mm) |
| Width b | 3 in (76.2 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 | 12.17 lb/ft (18.1 kg/m) |
| 20 ft bar | 243 lb |
| 40 ft bar | 487 lb |
| Area A | 3.39 in² (21.9 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 3.78 in⁴ (157 cm⁴) |
| Section modulus Sx | 2.52 in³ (41 cm³) |
| Radius of gyration rx | 1.06 in |
| Moment of inertia Iy | 3.78 in⁴ (157 cm⁴) |
| Section modulus Sy | 2.52 in³ (41 cm³) |
| Radius of gyration ry | 1.06 in |
Compared with the neighbouring sizes
| Shape | h × b (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|
| HSS3x3x5/16 | 3 × 3 | 10.58 | 3.45 | 2.3 | −13 % | −9 % |
| HSS3x3x3/8 (this page) | 3 × 3 | 12.17 | 3.78 | 2.52 | — | — |
Deflection example
A simply supported HSS3x3x3/8 spanning 5 ft with a 10 kip point load at midspan deflects 0.41 in (E = 29,000 ksi, Ix = 3.78 in⁴). The L/360 serviceability limit for this span is 0.17 in — the shape does NOT pass this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a HSS3x3x3/8 tube weigh?
HSS3x3x3/8 weighs 12.17 pounds per foot (18.1 kg/m). A 20 ft bar weighs 243 lb and a 40 ft bar 487 lb.
What are the dimensions of a HSS3x3x3/8?
HSS3x3x3/8 is 3×3 in (76.2×76.2 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 HSS3x3x3/8 in mm?
HSS3x3x3/8 is 76.2×76.2 mm outside with a nominal wall of 9.5 mm. In metric section properties: Ix = 157 cm⁴, Sx = 41 cm³.
How much does a HSS3x3x3/8 weigh in kg?
18.1 kg per meter. A 6 m bar weighs 109 kg and a 12 m bar 217 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a HSS3x3x3/8?
About the strong axis, Ix = 3.78 in⁴ (157 cm⁴) with section modulus Sx = 2.52 in³. About the weak axis, Iy = 3.78 in⁴ and Sy = 2.52 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
HSS3x3x3/8 or HSS3x3x5/16 — what does one size down change?
HSS3x3x5/16 is about 13% lighter (10.58 vs 12.17 lb/ft) but about 9% less stiff (Ix 3.45 vs 3.78 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