W18x106 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W18x106 is an American wide-flange beam 18.7 inches (475 mm) deep with a 11.2 in (284.5 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 | 18.7 in (475 mm) |
| Flange width bf | 11.2 in (284.5 mm) |
| Web thickness tw | 0.59 in (15 mm) |
| Flange thickness tf | 0.94 in (23.9 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 | 31.1 in² (200.6 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 1,910 in⁴ (79,500 cm⁴) |
| Section modulus Sx | 204 in³ (3,343 cm³) |
| Radius of gyration rx | 7.84 in |
| Moment of inertia Iy | 220 in⁴ (9,157 cm⁴) |
| Section modulus Sy | 39.4 in³ (646 cm³) |
| Radius of gyration ry | 2.66 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W18x97 | 18.6 × 11.1 | 97 | 1,750 | 188 | −8 % | −8 % |
| W18x106 (this page) | 18.7 × 11.2 | 106 | 1,910 | 204 | — | — |
| W18x119 | 19 × 11.3 | 119 | 2,190 | 231 | +12 % | +15 % |
Deflection example
A simply supported W18x106 spanning 30 ft with a 10 kip point load at midspan deflects 0.18 in (E = 29,000 ksi, Ix = 1,910 in⁴). The L/360 serviceability limit for this span is 1 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W18x106 beam weigh?
W18x106 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 W18x106?
W18x106 is 18.7 in (475 mm) deep with a 11.2 in (284.5 mm) wide flange. The web is 0.59 in thick and the flanges are 0.94 in thick. Note the actual depth differs from the nominal W18 label — always design with the actual value.
What are the dimensions of a W18x106 in mm?
W18x106 is 475 mm deep with a 284.5 mm wide flange; the web is 15 mm and the flange 23.9 mm thick. In metric section properties: Ix = 79,500 cm⁴, Sx = 3,343 cm³.
How much does a W18x106 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 W18x106?
About the strong axis, Ix = 1,910 in⁴ (79,500 cm⁴) with section modulus Sx = 204 in³. About the weak axis, Iy = 220 in⁴ and Sy = 39.4 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W18x106 or W18x119 — what does one size up change?
W18x119 is about 12% heavier (119 vs 106 lb/ft) but about 15% stiffer (Ix 2,190 vs 1,910 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