W8×40 vs W8×48
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W8×48 is the heavier section at 48 lb per foot, versus 40 for W8×40 (8 lb/ft more).
Both are nominally 8 in. deep.
W8×48 has the greater bending strength: section modulus Sx of 43.2 in³ versus 35.5, about 22% more.
| Property | W8×40 | W8×48 |
|---|---|---|
| Weight | 40 lb/ft | 48 lb/ft |
| Depth (d) | 8 1/4" | 8 1/2" |
| Flange width (bf) | 8 1/8" | 8 1/8" |
| Web thickness (tw) | 3/8" | 3/8" |
| Flange thickness (tf) | 9/16" | 11/16" |
| Area (A) | 11.7 in² | 14.1 in² |
| Moment of inertia (Ix) | 146 in⁴ | 184 in⁴ |
| Section modulus (Sx) | 35.5 in³ | 43.2 in³ |
| Plastic modulus (Zx) | 39.8 in³ | 49 in³ |
Open W8×40 in the interactive size chart →
Full detail: W8×40 · W8×48. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
Browse more: size comparisons · Steel Beam Size Chart