W21×248 vs W21×275
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W21×275 is the heavier section at 275 lb per foot, versus 248 for W21×248 (27 lb/ft more).
Both are nominally 21 in. deep.
W21×275 has the greater bending strength: section modulus Sx of 638 in³ versus 576, about 11% more.
| Property | W21×248 | W21×275 |
|---|---|---|
| Weight | 248 lb/ft | 275 lb/ft |
| Depth (d) | 23 3/4" | 24 1/8" |
| Flange width (bf) | 12 3/4" | 12 7/8" |
| Web thickness (tw) | 1 1/8" | 1 1/4" |
| Flange thickness (tf) | 2" | 2 3/16" |
| Area (A) | 73.8 in² | 81.8 in² |
| Moment of inertia (Ix) | 6830 in⁴ | 7690 in⁴ |
| Section modulus (Sx) | 576 in³ | 638 in³ |
| Plastic modulus (Zx) | 671 in³ | 749 in³ |
Open W21×248 in the interactive size chart →
Full detail: W21×248 · W21×275. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
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