W18x143 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W18x143 is an American wide-flange beam 19.5 inches (495.3 mm) deep with a 11.2 in (284.5 mm) flange, weighing 143 pounds per foot (212.8 kg/m) — that is what the "143" 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 | 19.5 in (495.3 mm) |
| Flange width bf | 11.2 in (284.5 mm) |
| Web thickness tw | 0.73 in (18.5 mm) |
| Flange thickness tf | 1.32 in (33.5 mm) |
Weight & Cross-Section
| Weight per foot | 143 lb/ft (212.8 kg/m) |
| 20 ft bar | 2,860 lb |
| 40 ft bar | 5,720 lb |
| Area A | 42 in² (271 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 2,750 in⁴ (114,463 cm⁴) |
| Section modulus Sx | 282 in³ (4,621 cm³) |
| Radius of gyration rx | 8.09 in |
| Moment of inertia Iy | 311 in⁴ (12,945 cm⁴) |
| Section modulus Sy | 55.5 in³ (909 cm³) |
| Radius of gyration ry | 2.72 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W18x130 | 19.3 × 11.2 | 130 | 2,460 | 256 | −9 % | −11 % |
| W18x143 (this page) | 19.5 × 11.2 | 143 | 2,750 | 282 | — | — |
| W18x158 | 19.7 × 11.3 | 158 | 3,060 | 310 | +10 % | +11 % |
Deflection example
A simply supported W18x143 spanning 31 ft with a 10 kip point load at midspan deflects 0.13 in (E = 29,000 ksi, Ix = 2,750 in⁴). The L/360 serviceability limit for this span is 1.03 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W18x143 beam weigh?
W18x143 weighs 143 pounds per foot (212.8 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 2,860 lb and a 40 ft bar 5,720 lb.
What are the dimensions of a W18x143?
W18x143 is 19.5 in (495.3 mm) deep with a 11.2 in (284.5 mm) wide flange. The web is 0.73 in thick and the flanges are 1.32 in thick. Note the actual depth differs from the nominal W18 label — always design with the actual value.
What are the dimensions of a W18x143 in mm?
W18x143 is 495.3 mm deep with a 284.5 mm wide flange; the web is 18.5 mm and the flange 33.5 mm thick. In metric section properties: Ix = 114,463 cm⁴, Sx = 4,621 cm³.
How much does a W18x143 weigh in kg?
212.8 kg per meter. A 6 m bar weighs 1,277 kg and a 12 m bar 2,554 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W18x143?
About the strong axis, Ix = 2,750 in⁴ (114,463 cm⁴) with section modulus Sx = 282 in³. About the weak axis, Iy = 311 in⁴ and Sy = 55.5 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W18x143 or W18x158 — what does one size up change?
W18x158 is about 10% heavier (158 vs 143 lb/ft) but about 11% stiffer (Ix 3,060 vs 2,750 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