W12x30 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W12x30 is an American wide-flange beam 12.3 inches (312.4 mm) deep with a 6.52 in (165.6 mm) flange, weighing 30 pounds per foot (44.6 kg/m) — that is what the "30" 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 | 12.3 in (312.4 mm) |
| Flange width bf | 6.52 in (165.6 mm) |
| Web thickness tw | 0.26 in (6.6 mm) |
| Flange thickness tf | 0.44 in (11.2 mm) |
Weight & Cross-Section
| Weight per foot | 30 lb/ft (44.6 kg/m) |
| 20 ft bar | 600 lb |
| 40 ft bar | 1,200 lb |
| Area A | 8.79 in² (56.7 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 238 in⁴ (9,906 cm⁴) |
| Section modulus Sx | 38.6 in³ (633 cm³) |
| Radius of gyration rx | 5.21 in |
| Moment of inertia Iy | 20.3 in⁴ (845 cm⁴) |
| Section modulus Sy | 6.24 in³ (102 cm³) |
| Radius of gyration ry | 1.52 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W12x26 | 12.2 × 6.49 | 26 | 204 | 33.4 | −13 % | −14 % |
| W12x30 (this page) | 12.3 × 6.52 | 30 | 238 | 38.6 | — | — |
| W12x35 | 12.5 × 6.56 | 35 | 285 | 45.6 | +17 % | +20 % |
Deflection example
A simply supported W12x30 spanning 20 ft with a 10 kip point load at midspan deflects 0.42 in (E = 29,000 ksi, Ix = 238 in⁴). The L/360 serviceability limit for this span is 0.67 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W12x30 beam weigh?
W12x30 weighs 30 pounds per foot (44.6 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 600 lb and a 40 ft bar 1,200 lb.
What are the dimensions of a W12x30?
W12x30 is 12.3 in (312.4 mm) deep with a 6.52 in (165.6 mm) wide flange. The web is 0.26 in thick and the flanges are 0.44 in thick. Note the actual depth differs from the nominal W12 label — always design with the actual value.
What are the dimensions of a W12x30 in mm?
W12x30 is 312.4 mm deep with a 165.6 mm wide flange; the web is 6.6 mm and the flange 11.2 mm thick. In metric section properties: Ix = 9,906 cm⁴, Sx = 633 cm³.
How much does a W12x30 weigh in kg?
44.6 kg per meter. A 6 m bar weighs 268 kg and a 12 m bar 536 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W12x30?
About the strong axis, Ix = 238 in⁴ (9,906 cm⁴) with section modulus Sx = 38.6 in³. About the weak axis, Iy = 20.3 in⁴ and Sy = 6.24 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W12x30 or W12x35 — what does one size up change?
W12x35 is about 17% heavier (35 vs 30 lb/ft) but about 20% stiffer (Ix 285 vs 238 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