Steel Beam Sizes / AISC / W-Shapes / W8 / W8x21
W8x21 Steel Beam Dimensions and Properties
AISC Wide flange · v16.0
Diagram, properties emphasis, and nearby alternatives use the selected unit system.
Section diagram
W8x21 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 | 21.00 lb/ft | 31.30 kg/m |
| Depth, d | 8.28 in | 210.00 mm |
| Flange width, bf | 5.27 in | 134.00 mm |
| tw | 0.250 in | 6.350 mm |
| tf | 0.400 in | 10.200 mm |
| Area | 6.16 in² | 3,970.00 mm² |
| Ix | 75.30 in⁴ | 31,300,000 mm⁴ |
| Iy | 9.77 in⁴ | 4,070,000 mm⁴ |
| Sx | 18.20 in³ | 298,000.00 mm³ |
| Sy | 3.71 in³ | 60,800.00 mm³ |
| Zx | 20.40 in³ | 334,000.00 mm³ |
| Zy | 5.69 in³ | 93,200.00 mm³ |
| rx | 3.49 in | 88.60 mm |
| ry | 1.26 in | 32.00 mm |
| J | 0.28 in⁴ | 117,000.00 mm⁴ |
| Cw | 152.00 in⁶ | 40,800,000,000 mm⁶ |
Alternatives
Useful nearby sections
Same-series weight neighbors, closest Ix, and a nearby depth series when available — with percent change versus W8x21.
Lighter in W8
W8x18
- Weight
- 18.0 lb/ft (-14%)
- Depth
- 8.14 in (-1.7%)
- Ix
- 61.9 in⁴ (-18%)
Heavier in W8
W8x24
- Weight
- 24.0 lb/ft (+14%)
- Depth
- 7.93 in (-4.2%)
- Ix
- 82.7 in⁴ (+9.8%)
Closest Iₓ in W8
W8x28
- Weight
- 28.0 lb/ft (+33%)
- Depth
- 8.06 in (-2.7%)
- Ix
- 98.0 in⁴ (+30%)
Similar weight in W10
W10x22
- Weight
- 22.0 lb/ft (+4.8%)
- Depth
- 10.20 in (+23%)
- Ix
- 118.0 in⁴ (+57%)
Source: AISC Shapes Database v16.0 · Methodology