W12x106 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W12x106 is an American wide-flange beam 12.9 inches (327.7 mm) deep with a 12.2 in (309.9 mm) flange, weighing 106 pounds per foot (157.7 kg/m) — that is what the "106" 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 | 12.9 in (327.7 mm) |
| Flange width bf | 12.2 in (309.9 mm) |
| Web thickness tw | 0.61 in (15.5 mm) |
| Flange thickness tf | 0.99 in (25.1 mm) |
Weight & Cross-Section
| Weight per foot | 106 lb/ft (157.7 kg/m) |
| 20 ft bar | 2,120 lb |
| 40 ft bar | 4,240 lb |
| Area A | 31.2 in² (201.3 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 933 in⁴ (38,834 cm⁴) |
| Section modulus Sx | 145 in³ (2,376 cm³) |
| Radius of gyration rx | 5.47 in |
| Moment of inertia Iy | 301 in⁴ (12,529 cm⁴) |
| Section modulus Sy | 49.3 in³ (808 cm³) |
| Radius of gyration ry | 3.11 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W12x96 | 12.7 × 12.2 | 96 | 833 | 131 | −9 % | −11 % |
| W12x106 (this page) | 12.9 × 12.2 | 106 | 933 | 145 | — | — |
| W12x120 | 13.1 × 12.3 | 120 | 1,070 | 163 | +13 % | +15 % |
Deflection example
A simply supported W12x106 spanning 21 ft with a 10 kip point load at midspan deflects 0.12 in (E = 29,000 ksi, Ix = 933 in⁴). The L/360 serviceability limit for this span is 0.7 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W12x106 beam weigh?
W12x106 weighs 106 pounds per foot (157.7 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 2,120 lb and a 40 ft bar 4,240 lb.
What are the dimensions of a W12x106?
W12x106 is 12.9 in (327.7 mm) deep with a 12.2 in (309.9 mm) wide flange. The web is 0.61 in thick and the flanges are 0.99 in thick. Note the actual depth differs from the nominal W12 label — always design with the actual value.
What are the dimensions of a W12x106 in mm?
W12x106 is 327.7 mm deep with a 309.9 mm wide flange; the web is 15.5 mm and the flange 25.1 mm thick. In metric section properties: Ix = 38,834 cm⁴, Sx = 2,376 cm³.
How much does a W12x106 weigh in kg?
157.7 kg per meter. A 6 m bar weighs 946 kg and a 12 m bar 1,893 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W12x106?
About the strong axis, Ix = 933 in⁴ (38,834 cm⁴) with section modulus Sx = 145 in³. About the weak axis, Iy = 301 in⁴ and Sy = 49.3 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W12x106 or W12x120 — what does one size up change?
W12x120 is about 13% heavier (120 vs 106 lb/ft) but about 15% stiffer (Ix 1,070 vs 933 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