W18x234 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W18x234 is an American wide-flange beam 21.1 inches (535.9 mm) deep with a 11.7 in (297.2 mm) flange, weighing 234 pounds per foot (348.2 kg/m) — that is what the "234" 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 | 21.1 in (535.9 mm) |
| Flange width bf | 11.7 in (297.2 mm) |
| Web thickness tw | 1.16 in (29.5 mm) |
| Flange thickness tf | 2.11 in (53.6 mm) |
Weight & Cross-Section
| Weight per foot | 234 lb/ft (348.2 kg/m) |
| 20 ft bar | 4,680 lb |
| 40 ft bar | 9,360 lb |
| Area A | 68.6 in² (442.6 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 4,900 in⁴ (203,953 cm⁴) |
| Section modulus Sx | 466 in³ (7,636 cm³) |
| Radius of gyration rx | 8.44 in |
| Moment of inertia Iy | 558 in⁴ (23,226 cm⁴) |
| Section modulus Sy | 95.8 in³ (1,570 cm³) |
| Radius of gyration ry | 2.85 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W18x211 | 20.7 × 11.6 | 211 | 4,330 | 419 | −10 % | −12 % |
| W18x234 (this page) | 21.1 × 11.7 | 234 | 4,900 | 466 | — | — |
| W18x258 | 21.5 × 11.8 | 258 | 5,510 | 514 | +10 % | +12 % |
Deflection example
A simply supported W18x234 spanning 34 ft with a 10 kip point load at midspan deflects 0.1 in (E = 29,000 ksi, Ix = 4,900 in⁴). The L/360 serviceability limit for this span is 1.13 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W18x234 beam weigh?
W18x234 weighs 234 pounds per foot (348.2 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 4,680 lb and a 40 ft bar 9,360 lb.
What are the dimensions of a W18x234?
W18x234 is 21.1 in (535.9 mm) deep with a 11.7 in (297.2 mm) wide flange. The web is 1.16 in thick and the flanges are 2.11 in thick. Note the actual depth differs from the nominal W18 label — always design with the actual value.
What are the dimensions of a W18x234 in mm?
W18x234 is 535.9 mm deep with a 297.2 mm wide flange; the web is 29.5 mm and the flange 53.6 mm thick. In metric section properties: Ix = 203,953 cm⁴, Sx = 7,636 cm³.
How much does a W18x234 weigh in kg?
348.2 kg per meter. A 6 m bar weighs 2,089 kg and a 12 m bar 4,179 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W18x234?
About the strong axis, Ix = 4,900 in⁴ (203,953 cm⁴) with section modulus Sx = 466 in³. About the weak axis, Iy = 558 in⁴ and Sy = 95.8 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W18x234 or W18x258 — what does one size up change?
W18x258 is about 10% heavier (258 vs 234 lb/ft) but about 12% stiffer (Ix 5,510 vs 4,900 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