W8x28 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W8x28 is an American wide-flange beam 8.06 inches (204.7 mm) deep with a 6.54 in (166.1 mm) flange, weighing 28 pounds per foot (41.7 kg/m) — that is what the "28" in the designation means. All values below are the standard AISC published section properties used in US structural design, with metric equivalents alongside.
Typical uses: floor and roof framing, columns, headers, and general steel construction. For a quick stiffness check, see the deflection example below or open the beam calculator with your own span and load.
Dimensions
| Depth d | 8.06 in (204.7 mm) |
| Flange width bf | 6.54 in (166.1 mm) |
| Web thickness tw | 0.285 in (7.2 mm) |
| Flange thickness tf | 0.465 in (11.8 mm) |
Weight & Cross-Section
| Weight per foot | 28 lb/ft (41.7 kg/m) |
| 20 ft bar | 560 lb |
| 40 ft bar | 1,120 lb |
| Area A | 8.24 in² (53.2 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 98 in⁴ (4,079 cm⁴) |
| Section modulus Sx | 24.3 in³ (398 cm³) |
| Radius of gyration rx | 3.45 in |
| Moment of inertia Iy | 21.7 in⁴ (903 cm⁴) |
| Section modulus Sy | 6.63 in³ (109 cm³) |
| Radius of gyration ry | 1.62 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W8x24 | 7.93 × 6.5 | 24 | 82.7 | 20.9 | −14 % | −16 % |
| W8x28 (this page) | 8.06 × 6.54 | 28 | 98 | 24.3 | — | — |
| W8x31 | 8 × 8 | 31 | 110 | 27.5 | +11 % | +12 % |
Deflection example
A simply supported W8x28 spanning 13 ft with a 10 kip point load at midspan deflects 0.28 in (E = 29,000 ksi, Ix = 98 in⁴). The L/360 serviceability limit for this span is 0.43 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W8x28 beam weigh?
W8x28 weighs 28 pounds per foot (41.7 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 560 lb and a 40 ft bar 1,120 lb.
What are the dimensions of a W8x28?
W8x28 is 8.06 in (204.7 mm) deep with a 6.54 in (166.1 mm) wide flange. The web is 0.29 in thick and the flanges are 0.47 in thick. Note the actual depth differs from the nominal W8 label — always design with the actual value.
What are the dimensions of a W8x28 in mm?
W8x28 is 204.7 mm deep with a 166.1 mm wide flange; the web is 7.2 mm and the flange 11.8 mm thick. In metric section properties: Ix = 4,079 cm⁴, Sx = 398 cm³.
How much does a W8x28 weigh in kg?
41.7 kg per meter. A 6 m bar weighs 250 kg and a 12 m bar 500 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W8x28?
About the strong axis, Ix = 98 in⁴ (4,079 cm⁴) with section modulus Sx = 24.3 in³. About the weak axis, Iy = 21.7 in⁴ and Sy = 6.63 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W8x28 or W8x31 — what does one size up change?
W8x31 is about 11% heavier (31 vs 28 lb/ft) but about 12% stiffer (Ix 110 vs 98 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