W21x111 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W21x111 is an American wide-flange beam 21.5 inches (546.1 mm) deep with a 12.3 in (312.4 mm) flange, weighing 111 pounds per foot (165.2 kg/m) — that is what the "111" in the designation means. All values below are the standard AISC published section properties used in US structural design, with metric equivalents alongside.
Typical uses: floor and roof framing, columns, headers, and general steel construction. For a quick stiffness check, see the deflection example below or open the beam calculator with your own span and load.
Dimensions
| Depth d | 21.5 in (546.1 mm) |
| Flange width bf | 12.3 in (312.4 mm) |
| Web thickness tw | 0.55 in (14 mm) |
| Flange thickness tf | 0.875 in (22.2 mm) |
Weight & Cross-Section
| Weight per foot | 111 lb/ft (165.2 kg/m) |
| 20 ft bar | 2,220 lb |
| 40 ft bar | 4,440 lb |
| Area A | 32.6 in² (210.3 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 2,670 in⁴ (111,133 cm⁴) |
| Section modulus Sx | 249 in³ (4,080 cm³) |
| Radius of gyration rx | 9.05 in |
| Moment of inertia Iy | 274 in⁴ (11,405 cm⁴) |
| Section modulus Sy | 44.5 in³ (729 cm³) |
| Radius of gyration ry | 2.9 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W21x101 | 21.4 × 12.3 | 101 | 2,420 | 227 | −9 % | −9 % |
| W21x111 (this page) | 21.5 × 12.3 | 111 | 2,670 | 249 | — | — |
| W21x122 | 21.7 × 12.4 | 122 | 2,960 | 273 | +10 % | +11 % |
Deflection example
A simply supported W21x111 spanning 34 ft with a 10 kip point load at midspan deflects 0.18 in (E = 29,000 ksi, Ix = 2,670 in⁴). The L/360 serviceability limit for this span is 1.13 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W21x111 beam weigh?
W21x111 weighs 111 pounds per foot (165.2 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 2,220 lb and a 40 ft bar 4,440 lb.
What are the dimensions of a W21x111?
W21x111 is 21.5 in (546.1 mm) deep with a 12.3 in (312.4 mm) wide flange. The web is 0.55 in thick and the flanges are 0.88 in thick. Note the actual depth differs from the nominal W21 label — always design with the actual value.
What are the dimensions of a W21x111 in mm?
W21x111 is 546.1 mm deep with a 312.4 mm wide flange; the web is 14 mm and the flange 22.2 mm thick. In metric section properties: Ix = 111,133 cm⁴, Sx = 4,080 cm³.
How much does a W21x111 weigh in kg?
165.2 kg per meter. A 6 m bar weighs 991 kg and a 12 m bar 1,982 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W21x111?
About the strong axis, Ix = 2,670 in⁴ (111,133 cm⁴) with section modulus Sx = 249 in³. About the weak axis, Iy = 274 in⁴ and Sy = 44.5 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W21x111 or W21x122 — what does one size up change?
W21x122 is about 10% heavier (122 vs 111 lb/ft) but about 11% stiffer (Ix 2,960 vs 2,670 in⁴). Going one step up within the same depth group is usually the cheapest way to cut deflection.
Values are entered from the governing standard’s published tables and cross-checked programmatically against its mass and section formulas before publication. Spotted an error? Write to advertising@metalabout.net — verified corrections ship within days. About