W18×258 vs W27×258
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W18×258 and W27×258 both weigh 258 lb per foot, so the choice comes down to depth and stiffness rather than weight.
W27×258 is the deeper section at a nominal 27 in., versus 18 in.
W27×258 has the greater bending strength: section modulus Sx of 745 in³ versus 514, about 45% more.
| Property | W18×258 | W27×258 |
|---|---|---|
| Weight | 258 lb/ft | 258 lb/ft |
| Depth (d) | 21 1/2" | 29" |
| Flange width (bf) | 11 3/4" | 14 1/4" |
| Web thickness (tw) | 1 1/4" | 1" |
| Flange thickness (tf) | 2 5/16" | 1 3/4" |
| Area (A) | 76 in² | 76.1 in² |
| Moment of inertia (Ix) | 5510 in⁴ | 10800 in⁴ |
| Section modulus (Sx) | 514 in³ | 745 in³ |
| Plastic modulus (Zx) | 611 in³ | 852 in³ |
Open W18×258 in the interactive size chart →
Full detail: W18×258 · W27×258. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
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