W18x76 — Dimensions, Weight & Section Properties
American wide-flange (W) beam per ASTM A6 / AISC Steel Construction Manual
W18x76 is an American wide-flange beam 18.2 inches (462.3 mm) deep with a 11 in (279.4 mm) flange, weighing 76 pounds per foot (113.1 kg/m) — that is what the "76" 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 | 18.2 in (462.3 mm) |
| Flange width bf | 11 in (279.4 mm) |
| Web thickness tw | 0.425 in (10.8 mm) |
| Flange thickness tf | 0.68 in (17.3 mm) |
Weight & Cross-Section
| Weight per foot | 76 lb/ft (113.1 kg/m) |
| 20 ft bar | 1,520 lb |
| 40 ft bar | 3,040 lb |
| Area A | 22.3 in² (143.9 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 1,330 in⁴ (55,359 cm⁴) |
| Section modulus Sx | 146 in³ (2,393 cm³) |
| Radius of gyration rx | 7.73 in |
| Moment of inertia Iy | 152 in⁴ (6,327 cm⁴) |
| Section modulus Sy | 27.6 in³ (452 cm³) |
| Radius of gyration ry | 2.61 in |
Compared with the neighbouring sizes
| Shape | d × bf (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| W18x71 | 18.5 × 7.64 | 71 | 1,170 | 127 | −7 % | −12 % |
| W18x76 (this page) | 18.2 × 11 | 76 | 1,330 | 146 | — | — |
| W18x86 | 18.4 × 11.1 | 86 | 1,530 | 166 | +13 % | +15 % |
Deflection example
A simply supported W18x76 spanning 29 ft with a 10 kip point load at midspan deflects 0.23 in (E = 29,000 ksi, Ix = 1,330 in⁴). The L/360 serviceability limit for this span is 0.97 in — the shape passes this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a W18x76 beam weigh?
W18x76 weighs 76 pounds per foot (113.1 kg/m). The number after the "x" in the designation is always the weight in lb/ft. A 20 ft bar weighs 1,520 lb and a 40 ft bar 3,040 lb.
What are the dimensions of a W18x76?
W18x76 is 18.2 in (462.3 mm) deep with a 11 in (279.4 mm) wide flange. The web is 0.43 in thick and the flanges are 0.68 in thick. Note the actual depth differs from the nominal W18 label — always design with the actual value.
What are the dimensions of a W18x76 in mm?
W18x76 is 462.3 mm deep with a 279.4 mm wide flange; the web is 10.8 mm and the flange 17.3 mm thick. In metric section properties: Ix = 55,359 cm⁴, Sx = 2,393 cm³.
How much does a W18x76 weigh in kg?
113.1 kg per meter. A 6 m bar weighs 679 kg and a 12 m bar 1,357 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a W18x76?
About the strong axis, Ix = 1,330 in⁴ (55,359 cm⁴) with section modulus Sx = 146 in³. About the weak axis, Iy = 152 in⁴ and Sy = 27.6 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
W18x76 or W18x86 — what does one size up change?
W18x86 is about 13% heavier (86 vs 76 lb/ft) but about 15% stiffer (Ix 1,530 vs 1,330 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