HSS8x4x3/8 — Dimensions, Weight & Section Properties
Hollow structural section per ASTM A500 / AISC Steel Construction Manual
HSS8x4x3/8 is an American hollow structural section (HSS) 8×4 inches (203.2×101.6 mm) with a nominal 0.375 in wall, weighing 27.48 pounds per foot (40.9 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 | 8 in (203.2 mm) |
| Width b | 4 in (101.6 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 | 27.48 lb/ft (40.9 kg/m) |
| 20 ft bar | 550 lb |
| 40 ft bar | 1,099 lb |
| Area A | 7.58 in² (48.9 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 58.7 in⁴ (2,443 cm⁴) |
| Section modulus Sx | 14.7 in³ (241 cm³) |
| Radius of gyration rx | 2.78 in |
| Moment of inertia Iy | 19.6 in⁴ (816 cm⁴) |
| Section modulus Sy | 9.8 in³ (161 cm³) |
| Radius of gyration ry | 1.61 in |
Compared with the neighbouring sizes
| Shape | h × b (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| HSS8x4x1/4 | 8 × 4 | 19.02 | 42.5 | 10.6 | −31 % | −28 % |
| HSS8x4x3/8 (this page) | 8 × 4 | 27.48 | 58.7 | 14.7 | — | — |
| HSS8x4x1/2 | 8 × 4 | 35.24 | 71.8 | 17.9 | +28 % | +22 % |
Deflection example
A simply supported HSS8x4x3/8 spanning 13 ft with a 10 kip point load at midspan deflects 0.47 in (E = 29,000 ksi, Ix = 58.7 in⁴). The L/360 serviceability limit for this span is 0.43 in — the shape does NOT pass this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a HSS8x4x3/8 tube weigh?
HSS8x4x3/8 weighs 27.48 pounds per foot (40.9 kg/m). A 20 ft bar weighs 550 lb and a 40 ft bar 1,099 lb.
What are the dimensions of a HSS8x4x3/8?
HSS8x4x3/8 is 8×4 in (203.2×101.6 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 HSS8x4x3/8 in mm?
HSS8x4x3/8 is 203.2×101.6 mm outside with a nominal wall of 9.5 mm. In metric section properties: Ix = 2,443 cm⁴, Sx = 241 cm³.
How much does a HSS8x4x3/8 weigh in kg?
40.9 kg per meter. A 6 m bar weighs 245 kg and a 12 m bar 491 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a HSS8x4x3/8?
About the strong axis, Ix = 58.7 in⁴ (2,443 cm⁴) with section modulus Sx = 14.7 in³. About the weak axis, Iy = 19.6 in⁴ and Sy = 9.8 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
HSS8x4x3/8 or HSS8x4x1/2 — what does one size up change?
HSS8x4x1/2 is about 28% heavier (35.24 vs 27.48 lb/ft) but about 22% stiffer (Ix 71.8 vs 58.7 in⁴). Going one step up within the same depth group is usually the cheapest way to cut deflection.
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