Steel Beam Sizes / AISC / W-Shapes / W21 / W21x55

W21x55 Steel Beam Dimensions and Properties

AISC Wide flange · v16.0

Analyze in Beam Calculator Back to W-Shapes All W21

Diagram, properties emphasis, and nearby alternatives use the selected unit system.

Units

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

Same-series weight neighbors, closest Ix, and a nearby depth series when available — with percent change versus W21x55.

Browse W21 series →

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%)

Closest Iₓ 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%)
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Source: AISC Shapes Database v16.0 · Methodology