W12x136 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W12x136 is an American wide-flange beam 13.4 inches (340.4 mm) deep with a 12.4 in (315 mm) flange, weighing 136 pounds per foot (202.4 kg/m) — that is what the "136" 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 | 13.4 in (340.4 mm) |
| Flange width bf | 12.4 in (315 mm) |
| Web thickness tw | 0.79 in (20.1 mm) |
| Flange thickness tf | 1.25 in (31.8 mm) |
Weight & Cross-Section
| Weight per foot | 136 lb/ft (202.4 kg/m) |
| 20 ft bar | 2,720 lb |
| 40 ft bar | 5,440 lb |
| Area A | 39.9 in² (257.4 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 1,240 in⁴ (51,613 cm⁴) |
| Section modulus Sx | 186 in³ (3,048 cm³) |
| Radius of gyration rx | 5.58 in |
| Moment of inertia Iy | 398 in⁴ (16,566 cm⁴) |
| Section modulus Sy | 64.2 in³ (1,052 cm³) |
| Radius of gyration ry | 3.16 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W12x120 | 13.1 × 12.3 | 120 | 1,070 | 163 | −12 % | −14 % |
| W12x136 (this page) | 13.4 × 12.4 | 136 | 1,240 | 186 | — | — |
| W12x152 | 13.7 × 12.5 | 152 | 1,430 | 209 | +12 % | +15 % |
Deflection example
A simply supported W12x136 spanning 21 ft with a 10 kip point load at midspan deflects 0.09 in (E = 29,000 ksi, Ix = 1,240 in⁴). The L/360 serviceability limit for this span is 0.7 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W12x136 beam weigh?
W12x136 weighs 136 pounds per foot (202.4 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 2,720 lb and a 40 ft bar 5,440 lb.
What are the dimensions of a W12x136?
W12x136 is 13.4 in (340.4 mm) deep with a 12.4 in (315 mm) wide flange. The web is 0.79 in thick and the flanges are 1.25 in thick. Note the actual depth differs from the nominal W12 label — always design with the actual value.
What are the dimensions of a W12x136 in mm?
W12x136 is 340.4 mm deep with a 315 mm wide flange; the web is 20.1 mm and the flange 31.8 mm thick. In metric section properties: Ix = 51,613 cm⁴, Sx = 3,048 cm³.
How much does a W12x136 weigh in kg?
202.4 kg per meter. A 6 m bar weighs 1,214 kg and a 12 m bar 2,429 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W12x136?
About the strong axis, Ix = 1,240 in⁴ (51,613 cm⁴) with section modulus Sx = 186 in³. About the weak axis, Iy = 398 in⁴ and Sy = 64.2 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W12x136 or W12x152 — what does one size up change?
W12x152 is about 12% heavier (152 vs 136 lb/ft) but about 15% stiffer (Ix 1,430 vs 1,240 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