Steel Angle Weight Formula

PRELIMINARY — NOT FOR CONSTRUCTION. All results are for educational and reference use only. Must be independently verified by a licensed Professional Engineer (PE) or Structural Engineer (SE) before use in any project.

The weight of any steel member follows a single fundamental relationship:

Weight = Cross-Sectional Area × Steel Density

For angles specifically, the weight per linear foot (lb/ft) is:

Weight (lb/ft) = A (in²) × 0.2833 (lb/in³) × 12 (in/ft)

Which simplifies to:

Weight (lb/ft) = A (in²) × 3.40

The constant 3.40 comes from multiplying the density of structural steel at 0.2833 lb/in³ by 12 inches per foot. Since the cross-sectional area A of the angle is in square inches, and density is in pounds per cubic inch, the product multiplied by 12 gives pounds per linear foot.

For metric units:

Weight (kg/m) = A (mm²) × 7850 (kg/m³) ÷ 1,000,000

Which simplifies to:

Weight (kg/m) = A (mm²) × 0.00785

The key input in every case is the cross-sectional area of the angle. Getting the area correct is the entire challenge of angle weight calculation.

Steel Density: The Universal Constant

Structural steel density is standardized at:

This density applies to all carbon structural steel grades: ASTM A36, A572 Grade 50, A992, AS/NZS 3678 Grade 350, EN 10025 S355, and CSA G40.21 Grade 350W. All standard structural steel grades share the same density within 1%, so the weight tables on this page are valid for all common grades.

For stainless steel angles, density is slightly higher: approximately 8000 kg/m³ (500 lb/ft³). If you are working with stainless steel angles, multiply the carbon steel weights in this article by approximately 1.02.

How to Calculate Angle Cross-Sectional Area

Equal-Leg Angle Area Formula

For an equal-leg angle with leg length b and thickness t, the cross-sectional area is:

A = t (2b - t)

This formula subtracts the overlap at the heel of the angle — the corner region that would be counted twice if you simply doubled the rectangular area of one leg. The derivation is straightforward: the total area is the area of two legs of width b and thickness t, minus the square overlap at the corner of dimension t × t.

Example calculation for L4×4×1/2:

• b = 4.0 in
• t = 0.5 in
• A = 0.5 × (2 × 4.0 - 0.5) = 0.5 × 7.5 = 3.75 in²

Weight per foot = 3.75 × 3.40 = 12.75 lb/ft (the AISC tabulated value is 12.8 lb/ft, matching within rounding).

Example calculation for L3×3×1/4:

• b = 3.0 in, t = 0.25 in
• A = 0.25 × (2 × 3.0 - 0.25) = 0.25 × 5.75 = 1.44 in²
• Weight = 1.44 × 3.40 = 4.89 lb/ft (AISC tabulated: 4.90 lb/ft)

The formula is exact for angles with a square corner (which is the AISC idealization). Actual hot-rolled angles have a slightly rounded heel, which reduces the area by a negligible amount (typically under 1%). For all practical weight estimation, use the formula directly.

Unequal-Leg Angle Area Formula

For an unequal-leg angle with long leg b, short leg d, and thickness t:

A = t (b + d - t)

The principle is the same: area of two rectangular legs minus the square overlap.

Example calculation for L4×3×1/2:

• b = 4.0 in, d = 3.0 in, t = 0.5 in
• A = 0.5 × (4.0 + 3.0 - 0.5) = 0.5 × 6.5 = 3.25 in²
• Weight = 3.25 × 3.40 = 11.05 lb/ft

Equal-Leg Angle Weight Table (lb/ft)

The table below lists common equal-leg angle sections from L1×1×1/8 through L8×8×1-1/8, with AISC-tabulated weight per foot and cross-sectional area. All values are from the AISC Steel Construction Manual, 16th edition.

Table 1: Equal-Leg Angle Weight Per Foot

Larger sections (L8×8×1-1/8 and above) are typically used as column base stiffeners, transfer girder connections, and crane runway angles. Always verify these section weights against the most recent AISC tables for design-critical applications.

Unequal-Leg Angle Weight Table (lb/ft)

Unequal-leg angles provide asymmetric strength where one leg carries additional load or spans a greater distance. They are common in lintels, connection angles where one leg bolts to a column and the other supports a beam, and architectural exposed structural steel where the proportions affect the visual aesthetic.

Table 2: Unequal-Leg Angle Weight Per Foot

Unequal-leg angles are most efficient when the applied loading aligns with the asymmetry: the longer leg carries higher bending stress, or engages a longer bolted connection length. When used as lintels, the vertical (long) leg resists bending while the horizontal (short) leg supports the masonry or cladding load.

Metric Angle Weight Conversion

For projects outside the United States, angle weight is typically expressed in kilograms per meter (kg/m). The conversion is:

Weight (kg/m) = Weight (lb/ft) × 1.4882

The factor 1.4882 combines the pound-to-kilogram conversion (0.4536) and the foot-to-meter conversion (3.281):

• 1 lb/ft = 0.4536 kg / 0.3048 m = 1.4882 kg/m

Quick reference for common size conversions:

For AS 4100 design (Australia and New Zealand), angle sections are designated in metric: e.g., 100×100×10 EA (Equal Angle) where leg length and thickness are in millimeters. The weight for a 100×100×10 EA can be directly calculated from the area formula:

• A = 10 × (2 × 100 - 10) = 1900 mm²
• Weight = 1900 × 7850 / 1,000,000 = 14.9 kg/m

This matches the AISC L4×4×3/8 (14.6 kg/m) closely — 100 mm is approximately 4 inches, and 10 mm is approximately 3/8 inch.

For EN 1993 (Eurocode) design, the standard hot-rolled equal angle sections follow EN 10056-1, with designations such as L 100×100×10. Weight values are listed in product standards at 7850 kg/m³ density.

Metric Angle Weight Table (AU/NZ Common Sizes)

For Australian and New Zealand projects, the following equal angle sizes are widely stocked and specified. Weights are calculated at 7850 kg/m³ per AS 4100.

Table 3: Metric Equal Angle Weight (AS/NZS 3679.1)

Australian unequal angles (UA) follow similar weight calculation methodology. For example, a 125×75×10 UA has:

• A = 10 × (125 + 75 - 10) = 1900 mm²
• Weight = 1900 × 0.00785 = 14.9 kg/m

For CSA S16 (Canada), angle designations match US practice: equal-leg angles follow the L[leg]×[leg]×[thickness] format, and for CSA G40.21 350W steel, the density is also 7850 kg/m³, producing identical weight-per-foot values.

How to Use the Free Steel Angle Weight Calculator

Manual calculation from the area formula works for single sections, but structural takeoffs involve dozens or hundreds of angle members across multiple sizes and lengths. The interactive angle weight calculator handles this efficiently:

Step 1 — Select your angle type. Choose equal-leg or unequal-leg from the dropdown. The calculator adjusts the input fields accordingly.

Step 2 — Enter section dimensions. Input leg dimensions and thickness in inches (imperial) or millimeters (metric). For imperial, use decimal inches (0.25, 0.375, 0.5) or fractional shorthand. For unequal-leg angles, enter both long and short leg values.

Step 3 — Enter length. Provide the total length of angle required: per piece, per bay, or per project total. The calculator accepts feet, inches, or meters.

Step 4 — Get instant results. The calculator returns weight per foot, total weight for the specified length, and the equivalent metric weight in kilograms. Results are computed using the exact A = t(2b - t) formula and standard steel density.

Step 5 — Export or save. Registered users can save weight calculations to their session history and export results as CSV or PDF for inclusion in calculation packages and material takeoffs.

The calculator also supports batch entry: input multiple angle sizes in a single session to generate a complete material weight summary for an entire framing bay or connection detail.

Comparison: Angle Weight vs Channel vs Flat Bar

For a given weight of steel, how does the angle section compare to alternative shapes? Understanding the weight-efficiency trade-offs helps with preliminary material selection.

Table 4: Weight Comparison — Angle vs Channel vs Flat Bar (per linear foot)

Key observations:

Angles are weight-efficient for tension and bracing. An angle used axially (in tension or as a brace) uses nearly all of its cross-sectional area efficiently. Bending capacity is direction-dependent and is lower per pound than a channel or W-shape oriented for strong-axis bending.

Channels are more efficient in bending than angles of comparable weight. The C4×5.4 at 5.4 lb/ft provides nearly double the strong-axis section modulus of an L4×4×3/8 at 9.8 lb/ft. When bending is the controlling limit state, a channel is typically the better choice.

Flat bars are the least structurally efficient. A flat bar 4 inches wide by 3/8 inch thick weighs 5.1 lb/ft — similar to an L4×4×1/4 at 6.6 lb/ft — but provides far less bending and buckling resistance. Flat bars are most appropriate as tension-only hangers, spacers, and shim plates.

Angles excel at connection detailing. Where a W-shape or channel requires a separate connection element, an angle can serve as both the structural member and the connection interface. This dual role often makes the angle the lightest and most cost-effective solution for bracing members and lintels.

Practical Angle Weight Applications in Steel Design

Dead Load Estimation for Angle Bracing

In a typical industrial building, diagonal rod or angle bracing runs between columns. For a bay with two L5×5×3/8 braces each 25 feet long:

• Weight per brace = 25 ft × 12.3 lb/ft = 307.5 lb
• Two braces = 615 lb
• Distributed over a 30-ft × 30-ft bay: 615 / 900 ft² = 0.68 psf

This is a light addition to the overall dead load, but for a building with 40 bays, the total brace steel weight exceeds 12 tons — a meaningful number for material procurement and erection planning.

Lintel Angle Weight Quick Check

For a window lintel using an L4×3×3/8 angle at 8.5 lb/ft spanning 6 feet:

• Lintel weight = 6 × 8.5 = 51 lb
• For 20 identical windows: 20 × 51 = 1,020 lb

This weight is small enough for manual handling without a crane, which simplifies sequencing on site. At approximately 50 lb per piece, a single ironworker can set lintel angles in place before the masonry contractor begins work above.

Shelf Angle for Brick Veneer

Shelf angles supporting brick veneer at each floor line are a common application. An L6×4×3/8 angle supporting 25 feet of brick veneer at 40 psf dead load carries approximately:

• Dead load on angle = 40 psf × 25 ft × 1 ft tributary width = 1,000 lb
• Angle self-weight = 25 ft × 12.3 lb/ft = 308 lb
• Total service load = 1,308 lb

The angle self-weight of 308 lb is more than 30% of the brick load — not negligible. For longer shelf angles, the self-weight of an L6×4×5/8 at 19.9 lb/ft becomes significant for both structural design and crane-assisted installation requirements.

Angle Weight Across Design Codes

While the density of structural steel is universal (490 lb/ft³ = 7850 kg/m³), angle section availability and designation formats vary by region. Understanding the equivalents across codes helps when specifying materials for international projects.

The weight of a given angle size is identical across all these codes because the density is the same. An L4×4×3/8 AISC angle and a 100×100×10 EA AS 4100 angle (approximate equivalent) have nearly identical weights: 9.8 lb/ft (14.6 kg/m) for both. The difference arises only from the slight dimensional variation between imperial and metric rounding.

Frequently Asked Questions

How much does a steel angle weigh per foot?

The weight depends entirely on the section size. A small L2×2×1/4 angle weighs 3.19 lb/ft, while a heavy L8×8×1 angle weighs 51.0 lb/ft. The most commonly specified angles in building construction — L4×4×3/8 and L5×5×3/8 — weigh 9.8 lb/ft and 12.3 lb/ft respectively. For any angle, weight can be calculated from the formula: Weight = t(2b - t) × 3.40, where t is thickness and b is leg length in inches. For metric: Weight (kg/m) = t(2b - t) × 0.00785 with dimensions in mm.

What is the weight of an L4×4×3/8 angle in kg/m?

An L4×4×3/8 angle weighs 9.8 lb/ft, which converts to 14.6 kg/m. This is one of the most frequently specified angle sizes for bracing, connections, and lintels. The approximate metric equivalent is a 100×100×10 EA, which weighs 14.9 kg/m — the slight difference is due to the 100 mm leg being about 0.5% shorter than 4 inches (101.6 mm).

How does angle weight compare to channel weight?

For the same nominal size, a channel is typically heavier than an angle because the channel web adds area. An L4×4×3/8 angle weighs 9.8 lb/ft, while a C4×5.4 channel weighs only 5.4 lb/ft — the channel is actually lighter because it is significantly thinner. Comparing at similar thickness: an L4×4×1/4 weighs 6.6 lb/ft and a C4×7.25 (closest comparable) weighs 7.25 lb/ft. The channel provides better bending resistance per pound due to its web, but the angle provides simpler bolted connections on both legs. For axial bracing applications, the angle is almost always more weight-efficient.

Run Your Angle Weight Calculation

→ Steel Weight Calculator — instant angle weight lookups for any equal-leg or unequal-leg section, with metric and imperial output.

→ Steel Angle Sizes Reference — complete section properties for AISC L-shapes including area, moment of inertia, section modulus, and b/t limits.

→ Beam Capacity Calculator — verify bending and shear capacity for angles used as lintels or flexural members.

Related Resources

• Steel Angle Sizes and Section Properties
• Structural Steel Weights — W, HSS, Angle, Channel Tables
• Steel Weight Calculator — Free Tool
• Plate Weight Calculator — Steel Plate lb/ft² and kg/m²
• Steel Channel Sizes and Weight Reference
• ASTM A36 Steel Properties — Yield, Tensile, Hardness
• Beam Capacity Calculator — Free Online Tool
• Load Combinations Calculator — ASCE 7 LRFD and ASD

All tabulated angle weights are from the AISC Steel Construction Manual, 16th edition, AS/NZS 3679.1, and EN 10056-1. Values are nominal. Verify with current code editions for design use. Stainless steel angles require a density adjustment to 8000 kg/m³ (500 lb/ft³).

Try it now: Check your steel angle weight with our free Steel Weight calculator →

Disclaimer (Educational Use Only)

This page is provided for general technical information and educational use only. It does not constitute professional engineering advice, a design service, or a substitute for an independent review by a qualified structural engineer. Any calculations, outputs, examples, and workflows discussed here are simplified descriptions intended to support understanding and preliminary estimation.

All real-world structural design depends on project-specific factors (loads, combinations, stability, detailing, fabrication, erection, tolerances, site conditions, and the governing standard and project specification). You are responsible for verifying inputs, validating results with an independent method, checking constructability and code compliance, and obtaining professional sign-off where required.

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