W24x104 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W24x104 is an American wide-flange beam 24.1 inches (612.1 mm) deep with a 12.8 in (325.1 mm) flange, weighing 104 pounds per foot (154.8 kg/m) — that is what the "104" 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 | 12.8 in (325.1 mm) |
| Web thickness tw | 0.5 in (12.7 mm) |
| Flange thickness tf | 0.75 in (19 mm) |
Weight & Cross-Section
| Weight per foot | 104 lb/ft (154.8 kg/m) |
| 20 ft bar | 2,080 lb |
| 40 ft bar | 4,160 lb |
| Area A | 30.7 in² (198.1 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 3,100 in⁴ (129,031 cm⁴) |
| Section modulus Sx | 258 in³ (4,228 cm³) |
| Radius of gyration rx | 10.1 in |
| Moment of inertia Iy | 259 in⁴ (10,780 cm⁴) |
| Section modulus Sy | 40.7 in³ (667 cm³) |
| Radius of gyration ry | 2.91 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W24x94 | 24.3 × 9.07 | 94 | 2,700 | 222 | −10 % | −13 % |
| W24x104 (this page) | 24.1 × 12.8 | 104 | 3,100 | 258 | — | — |
| W24x117 | 24.3 × 12.8 | 117 | 3,540 | 291 | +13 % | +14 % |
Deflection example
A simply supported W24x104 spanning 39 ft with a 10 kip point load at midspan deflects 0.24 in (E = 29,000 ksi, Ix = 3,100 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 W24x104 beam weigh?
W24x104 weighs 104 pounds per foot (154.8 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 2,080 lb and a 40 ft bar 4,160 lb.
What are the dimensions of a W24x104?
W24x104 is 24.1 in (612.1 mm) deep with a 12.8 in (325.1 mm) wide flange. The web is 0.5 in thick and the flanges are 0.75 in thick. Note the actual depth differs from the nominal W24 label — always design with the actual value.
What are the dimensions of a W24x104 in mm?
W24x104 is 612.1 mm deep with a 325.1 mm wide flange; the web is 12.7 mm and the flange 19 mm thick. In metric section properties: Ix = 129,031 cm⁴, Sx = 4,228 cm³.
How much does a W24x104 weigh in kg?
154.8 kg per meter. A 6 m bar weighs 929 kg and a 12 m bar 1,857 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W24x104?
About the strong axis, Ix = 3,100 in⁴ (129,031 cm⁴) with section modulus Sx = 258 in³. About the weak axis, Iy = 259 in⁴ and Sy = 40.7 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W24x104 or W24x117 — what does one size up change?
W24x117 is about 13% heavier (117 vs 104 lb/ft) but about 14% stiffer (Ix 3,540 vs 3,100 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