W12x35 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W12x35 is an American wide-flange beam 12.5 inches (317.5 mm) deep with a 6.56 in (166.6 mm) flange, weighing 35 pounds per foot (52.1 kg/m) — that is what the "35" 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 | 12.5 in (317.5 mm) |
| Flange width bf | 6.56 in (166.6 mm) |
| Web thickness tw | 0.3 in (7.6 mm) |
| Flange thickness tf | 0.52 in (13.2 mm) |
Weight & Cross-Section
| Weight per foot | 35 lb/ft (52.1 kg/m) |
| 20 ft bar | 700 lb |
| 40 ft bar | 1,400 lb |
| Area A | 10.3 in² (66.5 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 285 in⁴ (11,863 cm⁴) |
| Section modulus Sx | 45.6 in³ (747 cm³) |
| Radius of gyration rx | 5.25 in |
| Moment of inertia Iy | 24.5 in⁴ (1,020 cm⁴) |
| Section modulus Sy | 7.47 in³ (122 cm³) |
| Radius of gyration ry | 1.54 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W12x30 | 12.3 × 6.52 | 30 | 238 | 38.6 | −14 % | −16 % |
| W12x35 (this page) | 12.5 × 6.56 | 35 | 285 | 45.6 | — | — |
| W12x40 | 11.9 × 8.01 | 40 | 307 | 51.5 | +14 % | +8 % |
Deflection example
A simply supported W12x35 spanning 20 ft with a 10 kip point load at midspan deflects 0.35 in (E = 29,000 ksi, Ix = 285 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 W12x35 beam weigh?
W12x35 weighs 35 pounds per foot (52.1 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 700 lb and a 40 ft bar 1,400 lb.
What are the dimensions of a W12x35?
W12x35 is 12.5 in (317.5 mm) deep with a 6.56 in (166.6 mm) wide flange. The web is 0.3 in thick and the flanges are 0.52 in thick. Note the actual depth differs from the nominal W12 label — always design with the actual value.
What are the dimensions of a W12x35 in mm?
W12x35 is 317.5 mm deep with a 166.6 mm wide flange; the web is 7.6 mm and the flange 13.2 mm thick. In metric section properties: Ix = 11,863 cm⁴, Sx = 747 cm³.
How much does a W12x35 weigh in kg?
52.1 kg per meter. A 6 m bar weighs 313 kg and a 12 m bar 625 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W12x35?
About the strong axis, Ix = 285 in⁴ (11,863 cm⁴) with section modulus Sx = 45.6 in³. About the weak axis, Iy = 24.5 in⁴ and Sy = 7.47 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W12x35 or W12x40 — what does one size up change?
W12x40 is about 14% heavier (40 vs 35 lb/ft) but about 8% stiffer (Ix 307 vs 285 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