How do you calculate steel angle weight per foot?

Steel angle weight per foot is calculated using the cross-sectional area multiplied by the density of steel. The approximate formula for an equal leg angle is W (lb/ft) ≈ 2 × t × (L − 0.5t) × 3.40, where t is the leg thickness in inches and L is the leg length in inches. The factor 3.40 comes from steel density of 490 lb/ft³ divided by 144 in²/ft². For unequal leg angles, use W ≈ t × (L₁ + L₂ − t) × 3.40 where L₁ and L₂ are the two leg lengths. For example, an L4x4x1/4 equal leg angle weighs 6.22 lb/ft, while an L4x3x1/4 weighs 5.76 lb/ft. Published values in the AISC Steel Construction Manual (Table 1-7) are authoritative; the approximate formulas are for preliminary estimation only and deviate 2-5% from exact values due to fillet radii at the leg intersection.

What ASTM specifications apply to steel angles?

The primary ASTM specifications for steel angles are: ASTM A36 (Fy = 36 ksi) for general purpose structural angles, the most common and widely available specification; ASTM A572 Grade 50 (Fy = 50 ksi) for higher strength bracing and structural applications requiring a 39% strength increase over A36; ASTM A588 (Fy = 50 ksi) for weathering steel angles used in exposed structures where no paint is desired, forming a protective oxide patina; ASTM A500 Grade B (Fy = 46 ksi) or Grade C (Fy = 50 ksi), though primarily for HSS, some manufacturers produce angles to this specification. ASTM A36 angles are most common for non-critical applications; use A572 Gr 50 when higher strength or connection capacity governs. All structural angles must conform to ASTM A6 tolerances for straightness, twist, and cross-section dimensions.

What are typical applications for steel angles in construction?

Steel angles serve diverse structural applications: lintels (L4x4x1/4 to L6x6x3/8, single or double angle, spanning 4-8 ft over openings), light bracing (L3x3x1/4 to L4x4x3/8 for tension or compression in trusses and frames), connection clips (L4x3x3/8 to L6x4x1/2 for bolted or welded beam-to-column connections), framing for metal studs (L2x2x1/8 to L3x3x1/4 non-structural), base angles (L4x4x3/8 to L6x6x1/2 connecting columns to foundation), stair stringers (L5x3-1/2x3/8 to L6x4x1/2 for light stairs), cross bracing (L3x3x1/4 to L5x5x3/8 for horizontal and vertical braces in braced frames and towers), equipment supports (L4x4x3/8 to L6x6x1/2 for grating supports and pipe racks). Angle selection depends on load magnitude, connection geometry, and governing limit state (tension yielding, compression buckling, block shear, or flexural yielding).

How does angle leg thickness affect section properties?

Increasing angle leg thickness quadratically increases cross-sectional area and weight, linearly increases moment of inertia and section modulus: for L4x4 angles, going from 1/4" to 3/8" increases weight from 6.22 to 9.17 lb/ft (+47%), area from 1.82 to 2.69 in² (+48%), Ix from 1.89 to 2.68 in⁴ (+42%), and Sx increases proportionally. Shear lag affects tension capacity of single angles connected by one leg — AISC Table D3.1 provides shear lag factors U = 1 − x̄/L where x̄ is the centroid distance from the connected leg heel and L is the connection length. Thicker legs increase the eccentricity x̄, potentially reducing effective net area for bolted connections by 10-20% compared to thinner legs. For compression, AISC Section E5 requires consideration of flexural-torsional buckling for single angles due to the non-coincident centroid and shear center. The effective slenderness KL/r for equal leg angles governs as K = 1.0 for individual angle struts unless end restraint can be justified.

Steel Angle Weight — L Shape Weight per Foot Chart

Q: What is the difference between equal and unequal leg angles?

Equal leg angles have both legs of the same length (e.g., L4x4x1/4), producing symmetric properties about both axes with Ix = Iy. They are used for bracing, lintels, and general framing where axial or bending loads may act in either direction. Unequal leg angles have different leg lengths (e.g., L6x4x1/2), resulting in asymmetric section properties with Ix > Iy. They are used in connections, clip angles, and stair stringers where the long leg provides greater bending strength in one direction. Unequal leg angles offer a 15-40% weight savings for the same strong-axis capacity compared to equal leg angles, since material is concentrated where it carries load. Typical applications: equal leg for cross bracing and web members, unequal leg for connection clips, seat angles, and stiffeners where one leg carries the primary load path.

Steel angles (L shapes) are the most versatile structural shape. Used for connections, bracing, lintels, framing, and miscellaneous metal. This page provides weight per foot and section data for common steel angles.

Equal Leg Angles

Designation	Weight (lb/ft)	Area (in²)	Ix = Iy (in⁴)	rx (in)	zx (in³)
L2x2x1/8	1.55	0.45	0.11	0.49	—
L2x2x3/16	2.28	0.67	0.16	0.48	—
L2x2x1/4	2.97	0.87	0.20	0.48	—
L2-1/2x2-1/2x1/4	3.79	1.11	0.41	0.61	—
L2-1/2x2-1/2x3/8	5.55	1.63	0.57	0.59	—
L3x3x3/16	3.50	1.03	0.57	0.74	—
L3x3x1/4	4.59	1.35	0.73	0.74	—
L3x3x3/8	6.71	1.97	1.02	0.72	—
L3x3x1/2	8.69	2.55	1.26	0.70	—
L3-1/2x3-1/2x1/4	5.40	1.58	1.19	0.87	—
L3-1/2x3-1/2x3/8	7.93	2.33	1.68	0.85	—
L3-1/2x3-1/2x1/2	10.31	3.02	2.10	0.83	—
L4x4x1/4	6.22	1.82	1.89	1.02	—
L4x4x3/8	9.17	2.69	2.68	1.00	—
L4x4x1/2	11.96	3.51	3.37	0.98	—
L4x4x5/8	14.59	4.28	3.97	0.96	—
L5x5x1/4	7.84	2.30	3.76	1.28	—
L5x5x3/8	11.59	3.40	5.39	1.26	—
L5x5x1/2	15.19	4.46	6.84	1.24	—
L5x5x5/8	18.65	5.47	8.14	1.22	—
L6x6x3/8	14.01	4.11	9.52	1.52	—
L6x6x1/2	18.43	5.40	12.14	1.50	—
L6x6x5/8	22.69	6.65	14.62	1.48	—
L6x6x3/4	26.79	7.86	16.97	1.47	—
L7x7x3/8	16.43	4.82	15.38	1.79	—
L7x7x1/2	21.63	6.35	19.69	1.76	—
L7x7x5/8	26.69	7.83	23.74	1.74	—
L7x7x3/4	31.60	9.27	27.56	1.72	—
L8x8x1/2	24.84	7.29	30.07	2.03	—
L8x8x5/8	30.69	9.01	36.39	2.01	—
L8x8x3/4	36.39	10.67	42.30	1.99	—
L8x8x1	47.28	13.87	52.55	1.95	—

Unequal Leg Angles

Designation	Weight (lb/ft)	Area (in²)	Ix (in⁴)	rx (in)	Iy (in⁴)	ry (in)
L3x2x3/16	2.96	0.87	0.54	0.79	0.19	0.47
L3x2x1/4	3.89	1.14	0.69	0.78	0.24	0.46
L3x2x3/8	5.70	1.67	0.96	0.76	0.34	0.45
L4x3x1/4	5.76	1.69	2.01	1.09	0.87	0.72
L4x3x3/8	8.50	2.49	2.87	1.07	1.25	0.71
L4x3x1/2	11.10	3.25	3.63	1.06	1.59	0.70
L5x3x1/4	6.59	1.93	3.76	1.40	0.87	0.67
L5x3x3/8	9.73	2.86	5.40	1.37	1.26	0.66
L5x3x1/2	12.76	3.74	6.90	1.36	1.61	0.66
L5x3-1/2x3/8	10.26	3.01	5.66	1.37	2.27	0.87
L6x3-1/2x3/8	11.04	3.24	9.03	1.67	2.27	0.84
L6x3-1/2x1/2	14.50	4.25	11.56	1.65	2.93	0.83
L6x4x3/8	12.01	3.52	9.70	1.66	3.33	0.97
L6x4x1/2	15.80	4.63	12.48	1.64	4.30	0.96
L6x4x5/8	19.44	5.70	14.97	1.62	5.18	0.95
L8x4x1/2	18.36	5.38	27.10	2.24	4.30	0.89
L8x4x5/8	22.63	6.63	32.72	2.22	5.22	0.89
L8x6x1/2	21.06	6.17	31.25	2.25	14.40	1.53
L8x6x5/8	25.98	7.61	37.77	2.23	17.46	1.51

ASTM Specifications for Angles

Spec	Grade	Fy (ksi)	Common Use
A36	—	36	Most angles, general purpose
A572	Gr 50	50	Higher strength, bracing
A588	—	50	Weathering, exposed structures
A500	Gr B/C	46/50	Some manufacturers use A500

Typical Angle Applications

Application	Typical Size	Notes
Lintels	L4x4x1/4 to L6x6x3/8	Single or double angle, span 4-8 ft
Light bracing	L3x3x1/4 to L4x4x3/8	Tension or compression
Connection clips	L4x3x3/8 to L6x4x1/2	Bolted or welded
Framing (metal studs)	L2x2x1/8 to L3x3x1/4	Non-structural framing
Base angles	L4x4x3/8 to L6x6x1/2	Connecting columns to foundation
Stair stringers	L5x3-1/2x3/8 to L6x4x1/2	Light stairs
Cross bracing	L3x3x1/4 to L5x5x3/8	Horizontal and vertical braces
Equipment supports	L4x4x3/8 to L6x6x1/2	Grating supports, pipe racks

Weight Formula for Angles

Approximate weight per foot: W (lb/ft) ≈ 2 × t × (L - 0.5t) × 3.40

where t = thickness (in), L = leg length (in). For unequal legs, use each leg separately.

Example: L4x4x3/8: W ≈ 2 × 0.375 × (4 - 0.1875) × 3.40 ≈ 9.74 lb/ft (actual: 9.17 lb/ft due to fillet)

Frequently Asked Questions

How much does a 4x4x3/8 steel angle weigh? 9.17 lb/ft. A 20-foot piece weighs approximately 183 lb.

What is the most common structural steel angle? L4x4x3/8 (A36) is the most commonly used structural angle for connections, bracing, and miscellaneous steel.

What is the difference between equal and unequal leg angles? Equal leg angles have both legs the same length (e.g., L4x4). Unequal leg angles have different leg lengths (e.g., L4x3). Unequal legs are used when connection geometry requires different dimensions on each side.

Can angles be used as beams? Small angles (L3 to L5) can span short distances as lintels or light beams. The weak axis capacity is very low, so angles must be properly oriented. For longer spans, use W-shapes or channels.

Steel Weight Calculator — Weight by dimensions
Steel Weight per Foot — All shapes weight chart
Steel Channel Weight — C and MC shapes
Steel Plate Weight — Plate weight chart
Bolted Connections — Connection design

Disclaimer

This is a calculation tool, not a substitute for professional engineering certification. All results must be independently verified by a licensed Professional Engineer (PE) or Structural Engineer (SE) before use in construction, fabrication, or permit documents. The user is responsible for the accuracy of all inputs and the verification of all outputs.