W8x24 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W8x24 is an American wide-flange beam 7.93 inches (201.4 mm) deep with a 6.5 in (165.1 mm) flange, weighing 24 pounds per foot (35.7 kg/m) — that is what the "24" 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 | 7.93 in (201.4 mm) |
| Flange width bf | 6.5 in (165.1 mm) |
| Web thickness tw | 0.245 in (6.2 mm) |
| Flange thickness tf | 0.4 in (10.2 mm) |
Weight & Cross-Section
| Weight per foot | 24 lb/ft (35.7 kg/m) |
| 20 ft bar | 480 lb |
| 40 ft bar | 960 lb |
| Area A | 7.08 in² (45.7 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 82.7 in⁴ (3,442 cm⁴) |
| Section modulus Sx | 20.9 in³ (342 cm³) |
| Radius of gyration rx | 3.42 in |
| Moment of inertia Iy | 18.3 in⁴ (762 cm⁴) |
| Section modulus Sy | 5.63 in³ (92 cm³) |
| Radius of gyration ry | 1.61 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W8x21 | 8.28 × 5.27 | 21 | 75.3 | 18.2 | −12 % | −9 % |
| W8x24 (this page) | 7.93 × 6.5 | 24 | 82.7 | 20.9 | — | — |
| W8x28 | 8.06 × 6.54 | 28 | 98 | 24.3 | +17 % | +19 % |
Deflection example
A simply supported W8x24 spanning 13 ft with a 10 kip point load at midspan deflects 0.33 in (E = 29,000 ksi, Ix = 82.7 in⁴). The L/360 serviceability limit for this span is 0.43 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W8x24 beam weigh?
W8x24 weighs 24 pounds per foot (35.7 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 480 lb and a 40 ft bar 960 lb.
What are the dimensions of a W8x24?
W8x24 is 7.93 in (201.4 mm) deep with a 6.5 in (165.1 mm) wide flange. The web is 0.25 in thick and the flanges are 0.4 in thick. Note the actual depth differs from the nominal W8 label — always design with the actual value.
What are the dimensions of a W8x24 in mm?
W8x24 is 201.4 mm deep with a 165.1 mm wide flange; the web is 6.2 mm and the flange 10.2 mm thick. In metric section properties: Ix = 3,442 cm⁴, Sx = 342 cm³.
How much does a W8x24 weigh in kg?
35.7 kg per meter. A 6 m bar weighs 214 kg and a 12 m bar 429 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W8x24?
About the strong axis, Ix = 82.7 in⁴ (3,442 cm⁴) with section modulus Sx = 20.9 in³. About the weak axis, Iy = 18.3 in⁴ and Sy = 5.63 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W8x24 or W8x28 — what does one size up change?
W8x28 is about 17% heavier (28 vs 24 lb/ft) but about 19% stiffer (Ix 98 vs 82.7 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