W4×13 vs W8×13
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W4×13 and W8×13 both weigh 13 lb per foot, so the choice comes down to depth and stiffness rather than weight.
W8×13 is the deeper section at a nominal 8 in., versus 4 in.
W8×13 has the greater bending strength: section modulus Sx of 9.91 in³ versus 5.46, about 82% more.
| Property | W4×13 | W8×13 |
|---|---|---|
| Weight | 13 lb/ft | 13 lb/ft |
| Depth (d) | 4 1/8" | 8" |
| Flange width (bf) | 4" | 4" |
| Web thickness (tw) | 1/4" | 1/4" |
| Flange thickness (tf) | 3/8" | 1/4" |
| Area (A) | 3.83 in² | 3.84 in² |
| Moment of inertia (Ix) | 11.3 in⁴ | 39.6 in⁴ |
| Section modulus (Sx) | 5.46 in³ | 9.91 in³ |
| Plastic modulus (Zx) | 6.28 in³ | 11.4 in³ |
Open W4×13 in the interactive size chart →
Full detail: W4×13 · W8×13. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
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