Steel Beam Sizes / AISC / W-Shapes / W21 / W21x55
W21x55 Dimensions, Weight and Section Properties
AISC Wide flange · v16.0
W21x55: 20.8 in depth, 8.22 in flange width, 55 lb/ft weight. View the full dimensions and properties in imperial and metric units below.
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Section diagram
W21x55 dimensions
Not to scale. Dimensions shown for reference.
Section properties
Symbols match the steel section finder. Imperial and metric values are shown side by side.
| Property | Imperial | Metric |
|---|---|---|
| Weight | 55.00 lb/ft | 82.00 kg/m |
| Depth, d | 20.80 in | 528.00 mm |
| Flange width, bf | 8.22 in | 209.00 mm |
| tw | 0.375 in | 9.530 mm |
| tf | 0.522 in | 13.300 mm |
| Area | 16.20 in² | 10,500.00 mm² |
| Ix | 1,140.00 in⁴ | 475,000,000 mm⁴ |
| Iy | 48.40 in⁴ | 20,100,000 mm⁴ |
| Sx | 110.00 in³ | 1,800,000 mm³ |
| Sy | 11.80 in³ | 193,000.00 mm³ |
| Zx | 126.00 in³ | 2,060,000 mm³ |
| Zy | 18.40 in³ | 302,000.00 mm³ |
| rx | 8.40 in | 213.00 mm |
| ry | 1.73 in | 43.90 mm |
| J | 1.24 in⁴ | 516,000.00 mm⁴ |
| Cw | 4,980.00 in⁶ | 1,340,000,000,000 mm⁶ |
Alternatives
Useful nearby sections
Compare weight neighbors, another Ix option, and a nearby depth series when available, with percent change versus W21x55.
Lighter in W21
W21x50
- Weight
- 50.0 lb/ft (-9.1%)
- Depth
- 20.80 in (0.0%)
- Ix
- 984.0 in⁴ (-14%)
Heavier in W21
W21x57
- Weight
- 57.0 lb/ft (+3.6%)
- Depth
- 21.10 in (+1.4%)
- Ix
- 1,170.0 in⁴ (+2.6%)
Another Iₓ option in W21
W21x48
- Weight
- 48.0 lb/ft (-13%)
- Depth
- 20.60 in (-1.0%)
- Ix
- 959.0 in⁴ (-16%)
Similar weight in W24
W24x55
- Weight
- 55.0 lb/ft (0.0%)
- Depth
- 23.60 in (+13%)
- Ix
- 1,350.0 in⁴ (+18%)
Source: AISC Shapes Database v16.0 · Methodology