Structural Steel Weight Per Foot — W-Shape, HSS, Angle, and Channel Tables

Accurate steel weight data is fundamental to structural engineering practice. Whether you are preparing a material takeoff for a bid, estimating project costs, or calculating dead loads for structural analysis, knowing the weight per linear foot of each member type is a baseline requirement. Errors in weight estimation compound across hundreds of members and can significantly affect both budget accuracy and structural adequacy.

Structural steel has a unit weight of 490 lb/ft³ (0.2833 lb/in³). This single constant underlies every weight-per-foot value in the AISC tables. The weight per foot listed in standard section designations — such as the "90" in W14×90 — is derived directly from this density multiplied by the cross-sectional area of that member.

This reference page consolidates weight-per-foot data for the most commonly specified structural steel shapes: W-shapes (wide flange), HSS square and rectangular tubes, HSS round sections, steel angles, and C-channels. All values are from the AISC Steel Construction Manual, 16th edition.

W-Shape (Wide Flange) Weight Reference

Wide flange sections are the workhorse of structural steel framing. The section designation encodes both geometry and weight: W[nominal depth]×[weight in lb/ft]. A W18×35 is approximately 18 inches deep and weighs 35 lb/ft. Note that nominal depth is not always exact — actual depth varies by weight variant within a series.

W-shapes are grouped by nominal depth, and within each depth group, heavier sections achieve greater capacity through thicker flanges and webs rather than increased overall depth. This makes it possible to substitute a heavier section without changing connection geometry, which is a common design strategy for congested framing.

Table 1: Common W-Shapes by Weight Group

HSS Square and Rectangular Weight Reference

Hollow Structural Sections (HSS) are used for columns, braces, trusses, and architectural exposed structure. The section designation follows the format HSS [width]×[height]×[wall thickness], where all dimensions are nominal. Actual wall thickness is approximately 93% of the nominal value for ASTM A500 sections.

Table 2: HSS Square Sections

Table 3: Common HSS Rectangular Sections

Table 4: HSS Round (Pipe-Equivalent) Weight

Round HSS sections are designated by outside diameter and wall thickness: HSS [OD]×[wall]. These sections replace the older pipe designation system (Std, XS, XXS) in modern AISC practice.

Steel Angle Weight Reference (Equal-Leg)

Steel angles (L-shapes) are used extensively as bracing, lintels, connections, shelf angles for masonry support, and secondary framing. The designation format is L[leg]×[leg]×[thickness] for equal-leg angles.

Table 5: Equal-Leg Angle Weight Per Foot

Unequal-leg angles follow the same format: L[long leg]×[short leg]×[thickness]. Unequal-leg variants are common where one leg must span a greater distance or engage a specific connection geometry.

Steel Channel Weight Reference

C-channels (American Standard Channels) are designated by depth and weight: C[depth]×[weight]. Channels are used for purlins, girts, lintels, and as secondary members where a flat bearing surface on one side is beneficial.

Table 6: C-Shape Channel Weight Per Foot

MC-shapes (Miscellaneous Channels) provide wider flanges than standard C-shapes at comparable depths and are sometimes specified where greater lateral stability or connection area is required.

Using Steel Weight for Dead Load Calculation

The weight per linear foot of a beam can be converted to a uniformly distributed dead load in psf (pounds per square foot) by dividing by the tributary bay spacing:

w (lb/ft²) = member weight (lb/ft) / tributary bay spacing (ft)

For example, a W18×35 framing at 10 ft on center contributes:

w = 35 lb/ft / 10 ft = 3.5 lb/ft²

For a complete steel dead load estimate, account for all framing elements: primary beams, secondary beams, girders, columns (converted to an equivalent floor load), and connections. A typical allowance for steel framing dead load in a commercial building ranges from 10 to 20 psf, depending on the span configuration and section sizes selected.

For total member weight across a project:

Total weight (lb) = weight per foot (lb/ft) × total length (ft)
Total weight (tons) = Total weight (lb) / 2000

Material costs and crane requirements are typically estimated in tons of structural steel.

Weight-Based Section Selection Tips

Lighter does not always mean lower cost. Section selection involves trade-offs that extend well beyond material weight:

Fabrication complexity matters. A heavier, simpler section with standard connection geometry may cost less to fabricate than a lighter section requiring custom cope cuts, stiffeners, or moment connections. Shop labor costs typically exceed raw material costs for complex connections.

Availability affects lead times. Not all sections in the AISC manual are stocked domestically. Sections outside of the most common weight groups — particularly very light or very heavy sections — may require mill order quantities and extended lead times. Confirming availability with a steel supplier early in design avoids substitution requests during construction.

Depth constraints drive section choice. In floor systems with tight plenum requirements, minimizing beam depth may justify a heavier section. A W12×53 and a W16×31 have comparable moment capacity, but the shallower W12 series allows more clearance for mechanical distribution below the slab.

Column sections favor heavy W14 series. The W14 group spans from W14×22 to W14×808, enabling column size to be held constant through multiple floors while increasing wall thickness. This simplifies splices and base plate design across a building's height.

Check weak-axis properties for braces and struts. HSS and round sections offer equal stiffness in all directions, making them efficient for compression members where weak-axis buckling would otherwise control. For the same weight, an HSS 6×6×3/8 at 28.3 lb/ft provides significantly better biaxial bending resistance than an equivalent W-shape.

Frequently Asked Questions

How much does a steel beam weigh per foot?

It depends entirely on the section. Common floor beams in commercial construction typically range from 18 to 68 lb/ft. A W18×35 at 35 lb/ft is a frequently specified floor beam for moderate spans of 20 to 30 feet. For long-span transfer beams, sections such as W36×135 (135 lb/ft) or heavier are common. For light secondary framing, W8×18 at 18 lb/ft or similar sections are typical. The section designation always includes the weight per foot as the second number after the multiplication sign.

What does "W14×90" mean in a steel section designation?

The "W" indicates a wide flange section. The "14" is the nominal depth in inches — the actual depth of a W14×90 is 14.02 inches, close to but not exactly 14 inches. The "90" is the weight per linear foot in pounds: a W14×90 weighs 90 lb for every foot of length. This weight is a direct function of the cross-sectional area of the member, calculated using the standard steel density of 490 lb/ft³. Heavier sections within the W14 group have thicker flanges and webs, increasing both weight and structural capacity.

How do I calculate the dead load from steel framing?

Start by listing all steel members in a typical bay and their weights per foot. Divide each member's weight per foot by its tributary width to get a load in lb/ft². Sum all contributions — secondary beams, primary beams, girders — and convert columns to an equivalent floor load by spreading their weight over the bay area they serve. Add an allowance of 2 to 5 psf for connections and miscellaneous steel (plates, bolts, stiffeners). A typical steel framing dead load for a commercial office building is 10 to 15 psf. This value is used as part of the total dead load (D) in load combinations per ASCE 7, such as 1.2D + 1.6L for strength design.

Why does actual HSS wall thickness differ from the nominal designation?

HSS sections produced to ASTM A500 (cold-formed) have an actual wall thickness of approximately 93% of the nominal value listed in the designation. A section designated HSS 6×6×3/8 has a nominal wall thickness of 0.375 inches but an actual average wall thickness of about 0.349 inches. This difference arises from the manufacturing tolerance allowed by ASTM A500. The AISC tables already account for this by listing section properties based on the reduced design wall thickness. Always use AISC tabulated properties rather than computing properties from the nominal wall thickness directly.

How do I estimate total steel tonnage for a project?

Sum the length of each member type, multiply by the weight per linear foot, and divide by 2000 to convert pounds to tons. Organize the takeoff by member category: primary beams, secondary beams, columns, braces, and miscellaneous steel (connections, plates, stiffeners). A common rule of thumb for preliminary budgeting is 3 to 6 lb/ft² of floor area for office buildings, 5 to 9 lb/ft² for industrial buildings with heavy loads or long spans. These broad ranges account for structural framing only and exclude metal deck, stairs, and miscellaneous items. Always confirm with a member-by-member takeoff before committing to a bid price.

What is the unit weight of structural steel and why does it matter?

Structural steel has a unit weight of 490 lb/ft³ (7850 kg/m³ in SI units). This constant is used to derive the weight per foot for every section in the AISC tables: weight = area × 490 / 144 (converting in² to ft²). Getting this value wrong by even a small percentage compounds across hundreds of members and can noticeably shift the estimated dead load. It also affects the seismic mass calculation, since structural self-weight contributes directly to the effective seismic weight W used in equivalent lateral force procedures per ASCE 7 Section 12.7.2.

Run This Calculation

→ Beam Capacity Calculator — verify moment and shear capacity for any W-shape, HSS, angle, or channel from this weight table.

→ Load Combinations Calculator — apply steel self-weight as dead load in ASCE 7 LRFD or ASD combinations.

Related Resources

• Steel Beam Span Guide
• HSS Section Properties
• Steel Angle Sizes and Properties
• Steel Channel Sizes and Properties
• Beam Capacity Calculator
• column capacity calculator
• ASTM A36 Steel Properties

All weights from AISC Steel Construction Manual, 16th edition. Values are nominal. Verify with current AISC tables for design use.

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