W18×65 vs W18×71
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W18×71 is the heavier section at 71 lb per foot, versus 65 for W18×65 (6 lb/ft more).
Both are nominally 18 in. deep.
W18×71 has the greater bending strength: section modulus Sx of 127 in³ versus 117, about 9% more.
| Property | W18×65 | W18×71 |
|---|---|---|
| Weight | 65 lb/ft | 71 lb/ft |
| Depth (d) | 18 3/8" | 18 1/2" |
| Flange width (bf) | 7 5/8" | 7 5/8" |
| Web thickness (tw) | 7/16" | 1/2" |
| Flange thickness (tf) | 3/4" | 13/16" |
| Area (A) | 19.1 in² | 20.9 in² |
| Moment of inertia (Ix) | 1070 in⁴ | 1170 in⁴ |
| Section modulus (Sx) | 117 in³ | 127 in³ |
| Plastic modulus (Zx) | 133 in³ | 146 in³ |
Open W18×65 in the interactive size chart →
Full detail: W18×65 · W18×71. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
Browse more: size comparisons · Steel Beam Size Chart