W8x48 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W8x48 is an American wide-flange beam 8.5 inches (215.9 mm) deep with a 8.11 in (206 mm) flange, weighing 48 pounds per foot (71.4 kg/m) — that is what the "48" 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.
W8x48: cross-section drawn to scale from the AISC dimensions (d 8.5, bf 8.11, tw 0.4, tf 0.685 in)Dimensions
| Depth d | 8.5 in (215.9 mm) |
| Flange width bf | 8.11 in (206 mm) |
| Web thickness tw | 0.4 in (10.2 mm) |
| Flange thickness tf | 0.685 in (17.4 mm) |
Weight & Cross-Section
| Weight per foot | 48 lb/ft (71.4 kg/m) |
| 20 ft bar | 960 lb |
| 40 ft bar | 1,920 lb |
| Area A | 14.1 in² (91 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 184 in⁴ (7,659 cm⁴) |
| Section modulus Sx | 43.2 in³ (708 cm³) |
| Radius of gyration rx | 3.61 in |
| Moment of inertia Iy | 60.9 in⁴ (2,535 cm⁴) |
| Section modulus Sy | 15 in³ (246 cm³) |
| Radius of gyration ry | 2.08 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|
| W8x40 | 8.25 × 8.07 | 40 | 146 | 35.5 | −17 % | −21 % |
| W8x48 (this page) | 8.5 × 8.11 | 48 | 184 | 43.2 | — | — |
| W8x58 | 8.75 × 8.22 | 58 | 228 | 52 | +21 % | +24 % |
Deflection example
A simply supported W8x48 spanning 14 ft with a 10 kip point load at midspan deflects 0.19 in (E = 29,000 ksi, Ix = 184 in⁴). The L/360 serviceability limit for this span is 0.47 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W8x48 beam weigh?
W8x48 weighs 48 pounds per foot (71.4 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 960 lb and a 40 ft bar 1,920 lb.
What are the dimensions of a W8x48?
W8x48 is 8.5 in (215.9 mm) deep with a 8.11 in (206 mm) wide flange. The web is 0.4 in thick and the flanges are 0.69 in thick. Note the actual depth differs from the nominal W8 label — always design with the actual value.
What are the dimensions of a W8x48 in mm?
W8x48 is 215.9 mm deep with a 206 mm wide flange; the web is 10.2 mm and the flange 17.4 mm thick. In metric section properties: Ix = 7,659 cm⁴, Sx = 708 cm³.
How much does a W8x48 weigh in kg?
71.4 kg per meter. A 6 m bar weighs 429 kg and a 12 m bar 857 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W8x48?
About the strong axis, Ix = 184 in⁴ (7,659 cm⁴) with section modulus Sx = 43.2 in³. About the weak axis, Iy = 60.9 in⁴ and Sy = 15 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W8x48 or W8x58 — what does one size up change?
W8x58 is about 21% heavier (58 vs 48 lb/ft) but about 24% stiffer (Ix 228 vs 184 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