W12×65 vs W18×65
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W12×65 and W18×65 both weigh 65 lb per foot, so the choice comes down to depth and stiffness rather than weight.
W18×65 is the deeper section at a nominal 18 in., versus 12 in.
W18×65 has the greater bending strength: section modulus Sx of 117 in³ versus 87.9, about 33% more.
| Property | W12×65 | W18×65 |
|---|---|---|
| Weight | 65 lb/ft | 65 lb/ft |
| Depth (d) | 12 1/8" | 18 3/8" |
| Flange width (bf) | 12" | 7 5/8" |
| Web thickness (tw) | 3/8" | 7/16" |
| Flange thickness (tf) | 5/8" | 3/4" |
| Area (A) | 19.1 in² | 19.1 in² |
| Moment of inertia (Ix) | 533 in⁴ | 1070 in⁴ |
| Section modulus (Sx) | 87.9 in³ | 117 in³ |
| Plastic modulus (Zx) | 96.8 in³ | 133 in³ |
Open W12×65 in the interactive size chart →
Full detail: W12×65 · W18×65. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
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