W12x50 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W12x50 is an American wide-flange beam 12.2 inches (309.9 mm) deep with a 8.08 in (205.2 mm) flange, weighing 50 pounds per foot (74.4 kg/m) — that is what the "50" 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 | 12.2 in (309.9 mm) |
| Flange width bf | 8.08 in (205.2 mm) |
| Web thickness tw | 0.37 in (9.4 mm) |
| Flange thickness tf | 0.64 in (16.3 mm) |
Weight & Cross-Section
| Weight per foot | 50 lb/ft (74.4 kg/m) |
| 20 ft bar | 1,000 lb |
| 40 ft bar | 2,000 lb |
| Area A | 14.6 in² (94.2 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 391 in⁴ (16,275 cm⁴) |
| Section modulus Sx | 64.2 in³ (1,052 cm³) |
| Radius of gyration rx | 5.18 in |
| Moment of inertia Iy | 56.3 in⁴ (2,343 cm⁴) |
| Section modulus Sy | 13.9 in³ (228 cm³) |
| Radius of gyration ry | 1.96 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W12x45 | 12.1 × 8.05 | 45 | 348 | 57.7 | −10 % | −11 % |
| W12x50 (this page) | 12.2 × 8.08 | 50 | 391 | 64.2 | — | — |
| W12x53 | 12.1 × 10 | 53 | 425 | 70.6 | +6 % | +9 % |
Deflection example
A simply supported W12x50 spanning 20 ft with a 10 kip point load at midspan deflects 0.25 in (E = 29,000 ksi, Ix = 391 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 W12x50 beam weigh?
W12x50 weighs 50 pounds per foot (74.4 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 1,000 lb and a 40 ft bar 2,000 lb.
What are the dimensions of a W12x50?
W12x50 is 12.2 in (309.9 mm) deep with a 8.08 in (205.2 mm) wide flange. The web is 0.37 in thick and the flanges are 0.64 in thick. Note the actual depth differs from the nominal W12 label — always design with the actual value.
What are the dimensions of a W12x50 in mm?
W12x50 is 309.9 mm deep with a 205.2 mm wide flange; the web is 9.4 mm and the flange 16.3 mm thick. In metric section properties: Ix = 16,275 cm⁴, Sx = 1,052 cm³.
How much does a W12x50 weigh in kg?
74.4 kg per meter. A 6 m bar weighs 446 kg and a 12 m bar 893 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W12x50?
About the strong axis, Ix = 391 in⁴ (16,275 cm⁴) with section modulus Sx = 64.2 in³. About the weak axis, Iy = 56.3 in⁴ and Sy = 13.9 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W12x50 or W12x53 — what does one size up change?
W12x53 is about 6% heavier (53 vs 50 lb/ft) but about 9% stiffer (Ix 425 vs 391 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