W12x305 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W12x305 is an American wide-flange beam 16.3 inches (414 mm) deep with a 13.2 in (335.3 mm) flange, weighing 305 pounds per foot (453.9 kg/m) — that is what the "305" 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 | 16.3 in (414 mm) |
| Flange width bf | 13.2 in (335.3 mm) |
| Web thickness tw | 1.63 in (41.4 mm) |
| Flange thickness tf | 2.71 in (68.8 mm) |
Weight & Cross-Section
| Weight per foot | 305 lb/ft (453.9 kg/m) |
| 20 ft bar | 6,100 lb |
| 40 ft bar | 12,200 lb |
| Area A | 89.5 in² (577.4 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 3,550 in⁴ (147,762 cm⁴) |
| Section modulus Sx | 435 in³ (7,128 cm³) |
| Radius of gyration rx | 6.29 in |
| Moment of inertia Iy | 1,050 in⁴ (43,704 cm⁴) |
| Section modulus Sy | 159 in³ (2,606 cm³) |
| Radius of gyration ry | 3.42 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W12x279 | 15.9 × 13.1 | 279 | 3,110 | 393 | −9 % | −12 % |
| W12x305 (this page) | 16.3 × 13.2 | 305 | 3,550 | 435 | — | — |
| W12x336 | 16.8 × 13.4 | 336 | 4,060 | 483 | +10 % | +14 % |
Deflection example
A simply supported W12x305 spanning 26 ft with a 10 kip point load at midspan deflects 0.06 in (E = 29,000 ksi, Ix = 3,550 in⁴). The L/360 serviceability limit for this span is 0.87 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W12x305 beam weigh?
W12x305 weighs 305 pounds per foot (453.9 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 6,100 lb and a 40 ft bar 12,200 lb.
What are the dimensions of a W12x305?
W12x305 is 16.3 in (414 mm) deep with a 13.2 in (335.3 mm) wide flange. The web is 1.63 in thick and the flanges are 2.71 in thick. Note the actual depth differs from the nominal W12 label — always design with the actual value.
What are the dimensions of a W12x305 in mm?
W12x305 is 414 mm deep with a 335.3 mm wide flange; the web is 41.4 mm and the flange 68.8 mm thick. In metric section properties: Ix = 147,762 cm⁴, Sx = 7,128 cm³.
How much does a W12x305 weigh in kg?
453.9 kg per meter. A 6 m bar weighs 2,723 kg and a 12 m bar 5,447 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W12x305?
About the strong axis, Ix = 3,550 in⁴ (147,762 cm⁴) with section modulus Sx = 435 in³. About the weak axis, Iy = 1,050 in⁴ and Sy = 159 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W12x305 or W12x336 — what does one size up change?
W12x336 is about 10% heavier (336 vs 305 lb/ft) but about 14% stiffer (Ix 4,060 vs 3,550 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