Steel Beam Sizes / AISC / W-Shapes / W8 / W8x18
W8x18 Steel Beam Dimensions and Properties
AISC Wide flange · v16.0
Diagram, properties emphasis, and nearby alternatives use the selected unit system.
Section diagram
W8x18 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 | 18.00 lb/ft | 26.60 kg/m |
| Depth, d | 8.14 in | 207.00 mm |
| Flange width, bf | 5.25 in | 133.00 mm |
| tw | 0.230 in | 5.840 mm |
| tf | 0.330 in | 8.380 mm |
| Area | 5.26 in² | 3,390.00 mm² |
| Ix | 61.90 in⁴ | 25,800,000 mm⁴ |
| Iy | 7.97 in⁴ | 3,320,000 mm⁴ |
| Sx | 15.20 in³ | 249,000.00 mm³ |
| Sy | 3.04 in³ | 49,800.00 mm³ |
| Zx | 17.00 in³ | 279,000.00 mm³ |
| Zy | 4.66 in³ | 76,400.00 mm³ |
| rx | 3.43 in | 87.10 mm |
| ry | 1.23 in | 31.20 mm |
| J | 0.17 in⁴ | 71,600.00 mm⁴ |
| Cw | 122.00 in⁶ | 32,800,000,000 mm⁶ |
Alternatives
Useful nearby sections
Same-series weight neighbors, closest Ix, and a nearby depth series when available — with percent change versus W8x18.
Lighter in W8
W8x15
- Weight
- 15.0 lb/ft (-17%)
- Depth
- 8.11 in (-0.4%)
- Ix
- 48.0 in⁴ (-22%)
Heavier in W8
W8x21
- Weight
- 21.0 lb/ft (+17%)
- Depth
- 8.28 in (+1.7%)
- Ix
- 75.3 in⁴ (+22%)
Closest Iₓ in W8
W8x24
- Weight
- 24.0 lb/ft (+33%)
- Depth
- 7.93 in (-2.6%)
- Ix
- 82.7 in⁴ (+34%)
Similar weight in W10
W10x17
- Weight
- 17.0 lb/ft (-5.6%)
- Depth
- 10.10 in (+24%)
- Ix
- 81.9 in⁴ (+32%)
Source: AISC Shapes Database v16.0 · Methodology