W30x90 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W30x90 is an American wide-flange beam 29.5 inches (749.3 mm) deep with a 10.4 in (264.2 mm) flange, weighing 90 pounds per foot (133.9 kg/m) — that is what the "90" 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 | 29.5 in (749.3 mm) |
| Flange width bf | 10.4 in (264.2 mm) |
| Web thickness tw | 0.47 in (11.9 mm) |
| Flange thickness tf | 0.61 in (15.5 mm) |
Weight & Cross-Section
| Weight per foot | 90 lb/ft (133.9 kg/m) |
| 20 ft bar | 1,800 lb |
| 40 ft bar | 3,600 lb |
| Area A | 26.3 in² (169.7 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 3,610 in⁴ (150,259 cm⁴) |
| Section modulus Sx | 245 in³ (4,015 cm³) |
| Radius of gyration rx | 11.7 in |
| Moment of inertia Iy | 115 in⁴ (4,787 cm⁴) |
| Section modulus Sy | 22.1 in³ (362 cm³) |
| Radius of gyration ry | 2.09 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W30x90 (this page) | 29.5 × 10.4 | 90 | 3,610 | 245 | — | — |
| W30x99 | 29.7 × 10.5 | 99 | 3,990 | 269 | +10 % | +11 % |
Deflection example
A simply supported W30x90 spanning 47 ft with a 10 kip point load at midspan deflects 0.36 in (E = 29,000 ksi, Ix = 3,610 in⁴). The L/360 serviceability limit for this span is 1.57 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W30x90 beam weigh?
W30x90 weighs 90 pounds per foot (133.9 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 1,800 lb and a 40 ft bar 3,600 lb.
What are the dimensions of a W30x90?
W30x90 is 29.5 in (749.3 mm) deep with a 10.4 in (264.2 mm) wide flange. The web is 0.47 in thick and the flanges are 0.61 in thick. Note the actual depth differs from the nominal W30 label — always design with the actual value.
What are the dimensions of a W30x90 in mm?
W30x90 is 749.3 mm deep with a 264.2 mm wide flange; the web is 11.9 mm and the flange 15.5 mm thick. In metric section properties: Ix = 150,259 cm⁴, Sx = 4,015 cm³.
How much does a W30x90 weigh in kg?
133.9 kg per meter. A 6 m bar weighs 804 kg and a 12 m bar 1,607 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W30x90?
About the strong axis, Ix = 3,610 in⁴ (150,259 cm⁴) with section modulus Sx = 245 in³. About the weak axis, Iy = 115 in⁴ and Sy = 22.1 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W30x90 or W30x99 — what does one size up change?
W30x99 is about 10% heavier (99 vs 90 lb/ft) but about 11% stiffer (Ix 3,990 vs 3,610 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