W27x178 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W27x178 is an American wide-flange beam 27.8 inches (706.1 mm) deep with a 14.1 in (358.1 mm) flange, weighing 178 pounds per foot (264.9 kg/m) — that is what the "178" 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 | 27.8 in (706.1 mm) |
| Flange width bf | 14.1 in (358.1 mm) |
| Web thickness tw | 0.725 in (18.4 mm) |
| Flange thickness tf | 1.19 in (30.2 mm) |
Weight & Cross-Section
| Weight per foot | 178 lb/ft (264.9 kg/m) |
| 20 ft bar | 3,560 lb |
| 40 ft bar | 7,120 lb |
| Area A | 52.5 in² (338.7 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 7,020 in⁴ (292,193 cm⁴) |
| Section modulus Sx | 505 in³ (8,275 cm³) |
| Radius of gyration rx | 11.6 in |
| Moment of inertia Iy | 555 in⁴ (23,101 cm⁴) |
| Section modulus Sy | 78.8 in³ (1,291 cm³) |
| Radius of gyration ry | 3.25 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W27x161 | 27.6 × 14 | 161 | 6,310 | 458 | −10 % | −10 % |
| W27x178 (this page) | 27.8 × 14.1 | 178 | 7,020 | 505 | — | — |
Deflection example
A simply supported W27x178 spanning 44 ft with a 10 kip point load at midspan deflects 0.15 in (E = 29,000 ksi, Ix = 7,020 in⁴). The L/360 serviceability limit for this span is 1.47 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W27x178 beam weigh?
W27x178 weighs 178 pounds per foot (264.9 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 3,560 lb and a 40 ft bar 7,120 lb.
What are the dimensions of a W27x178?
W27x178 is 27.8 in (706.1 mm) deep with a 14.1 in (358.1 mm) wide flange. The web is 0.73 in thick and the flanges are 1.19 in thick. Note the actual depth differs from the nominal W27 label — always design with the actual value.
What are the dimensions of a W27x178 in mm?
W27x178 is 706.1 mm deep with a 358.1 mm wide flange; the web is 18.4 mm and the flange 30.2 mm thick. In metric section properties: Ix = 292,193 cm⁴, Sx = 8,275 cm³.
How much does a W27x178 weigh in kg?
264.9 kg per meter. A 6 m bar weighs 1,589 kg and a 12 m bar 3,179 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W27x178?
About the strong axis, Ix = 7,020 in⁴ (292,193 cm⁴) with section modulus Sx = 505 in³. About the weak axis, Iy = 555 in⁴ and Sy = 78.8 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W27x178 or W27x161 — what does one size down change?
W27x161 is about 10% lighter (161 vs 178 lb/ft) but about 10% less stiff (Ix 6,310 vs 7,020 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