W24x84 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W24x84 is an American wide-flange beam 24.1 inches (612.1 mm) deep with a 9.02 in (229.1 mm) flange, weighing 84 pounds per foot (125 kg/m) — that is what the "84" 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 | 24.1 in (612.1 mm) |
| Flange width bf | 9.02 in (229.1 mm) |
| Web thickness tw | 0.47 in (11.9 mm) |
| Flange thickness tf | 0.77 in (19.6 mm) |
Weight & Cross-Section
| Weight per foot | 84 lb/ft (125 kg/m) |
| 20 ft bar | 1,680 lb |
| 40 ft bar | 3,360 lb |
| Area A | 24.7 in² (159.4 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 2,370 in⁴ (98,647 cm⁴) |
| Section modulus Sx | 196 in³ (3,212 cm³) |
| Radius of gyration rx | 9.79 in |
| Moment of inertia Iy | 94.4 in⁴ (3,929 cm⁴) |
| Section modulus Sy | 20.9 in³ (342 cm³) |
| Radius of gyration ry | 1.95 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W24x76 | 23.9 × 8.99 | 76 | 2,100 | 176 | −10 % | −11 % |
| W24x84 (this page) | 24.1 × 9.02 | 84 | 2,370 | 196 | — | — |
| W24x94 | 24.3 × 9.07 | 94 | 2,700 | 222 | +12 % | +14 % |
Deflection example
A simply supported W24x84 spanning 39 ft with a 10 kip point load at midspan deflects 0.31 in (E = 29,000 ksi, Ix = 2,370 in⁴). The L/360 serviceability limit for this span is 1.3 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W24x84 beam weigh?
W24x84 weighs 84 pounds per foot (125 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 1,680 lb and a 40 ft bar 3,360 lb.
What are the dimensions of a W24x84?
W24x84 is 24.1 in (612.1 mm) deep with a 9.02 in (229.1 mm) wide flange. The web is 0.47 in thick and the flanges are 0.77 in thick. Note the actual depth differs from the nominal W24 label — always design with the actual value.
What are the dimensions of a W24x84 in mm?
W24x84 is 612.1 mm deep with a 229.1 mm wide flange; the web is 11.9 mm and the flange 19.6 mm thick. In metric section properties: Ix = 98,647 cm⁴, Sx = 3,212 cm³.
How much does a W24x84 weigh in kg?
125 kg per meter. A 6 m bar weighs 750 kg and a 12 m bar 1,500 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W24x84?
About the strong axis, Ix = 2,370 in⁴ (98,647 cm⁴) with section modulus Sx = 196 in³. About the weak axis, Iy = 94.4 in⁴ and Sy = 20.9 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W24x84 or W24x94 — what does one size up change?
W24x94 is about 12% heavier (94 vs 84 lb/ft) but about 14% stiffer (Ix 2,700 vs 2,370 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