W21×147 vs W21×166
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W21×166 is the heavier section at 166 lb per foot, versus 147 for W21×147 (19 lb/ft more).
Both are nominally 21 in. deep.
W21×166 has the greater bending strength: section modulus Sx of 380 in³ versus 329, about 16% more.
| Property | W21×147 | W21×166 |
|---|---|---|
| Weight | 147 lb/ft | 166 lb/ft |
| Depth (d) | 22" | 22 1/2" |
| Flange width (bf) | 12 1/2" | 12 3/8" |
| Web thickness (tw) | 3/4" | 3/4" |
| Flange thickness (tf) | 1 1/8" | 1 3/8" |
| Area (A) | 43.2 in² | 48.8 in² |
| Moment of inertia (Ix) | 3630 in⁴ | 4280 in⁴ |
| Section modulus (Sx) | 329 in³ | 380 in³ |
| Plastic modulus (Zx) | 373 in³ | 432 in³ |
Open W21×147 in the interactive size chart →
Full detail: W21×147 · W21×166. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
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