L4x3x3/8 — Dimensions, Weight & Section Properties
Steel angle (L-shape) per ASTM A6 / AISC Steel Construction Manual
L4x3x3/8 is a hot-rolled steel angle with a 4 in (101.6 mm) long leg and a 3 in (76.2 mm) short leg, 0.375 in thick, weighing 8.5 pounds per foot (12.6 kg/m). All values below are the standard AISC published section properties, with metric equivalents alongside.
Typical uses: bracing, lintels, shelf supports, frames, and connection material. Angles are weak about their minor axis — long unbraced angles need lateral restraint. For a quick check, see the deflection example below or open the beam calculator.
Dimensions
| Long leg | 4 in (101.6 mm) |
| Short leg | 3 in (76.2 mm) |
| Thickness t | 0.375 in (9.5 mm) |
Weight & Cross-Section
| Weight per foot | 8.5 lb/ft (12.6 kg/m) |
| 20 ft bar | 170 lb |
| 40 ft bar | 340 lb |
| Area A | 2.48 in² (16 cm²) |
Section Properties (strong / weak axis)
| Moment of inertia Ix | 3.94 in⁴ (164 cm⁴) |
| Section modulus Sx | 1.44 in³ (24 cm³) |
| Radius of gyration rx | 1.26 in |
| Moment of inertia Iy | 1.89 in⁴ (79 cm⁴) |
| Section modulus Sy | 0.85 in³ (14 cm³) |
| Radius of gyration ry | 0.87 in |
Compared with the neighbouring sizes
| Shape | legs (in) | lb/ft | Ix (in⁴) | Sx (in³) | Δ weight | Δ Ix |
|---|---|---|---|---|---|---|
| L4x3x1/4 | 4 × 3 | 5.8 | 2.75 | 0.99 | −32 % | −30 % |
| L4x3x3/8 (this page) | 4 × 3 | 8.5 | 3.94 | 1.44 | — | — |
Deflection example
A simply supported L4x3x3/8 spanning 6 ft with a 10 kip point load at midspan deflects 0.68 in (E = 29,000 ksi, Ix = 3.94 in⁴). The L/360 serviceability limit for this span is 0.2 in — the shape does NOT pass this quick check.
Calculate with your own span and load →
Frequently asked questions
How much does a L4x3x3/8 angle weigh?
L4x3x3/8 weighs 8.5 pounds per foot (12.6 kg/m). A 20 ft bar weighs 170 lb and a 40 ft bar 340 lb.
What are the dimensions of a L4x3x3/8?
L4x3x3/8 has a 4 in long leg and a 3 in short leg, both 0.375 in thick. Angle legs are measured outside-to-outside, and both legs share the same thickness.
What are the dimensions of a L4x3x3/8 in mm?
L4x3x3/8 has a 101.6 mm long leg and a 76.2 mm short leg, 9.5 mm thick. In metric section properties: Ix = 164 cm⁴, Sx = 24 cm³.
How much does a L4x3x3/8 weigh in kg?
12.6 kg per meter. A 6 m bar weighs 76 kg and a 12 m bar 152 kg — handy when ordering US shapes from metric suppliers.
What is the moment of inertia of a L4x3x3/8?
About the strong axis, Ix = 3.94 in⁴ (164 cm⁴) with section modulus Sx = 1.44 in³. About the weak axis, Iy = 1.89 in⁴ and Sy = 0.85 in³. Use the beam deflection calculator to turn these into deflection and stress for your span and load.
L4x3x3/8 or L4x3x1/4 — what does one size down change?
L4x3x1/4 is about 32% lighter (5.8 vs 8.5 lb/ft) but about 30% less stiff (Ix 2.75 vs 3.94 in⁴). Check deflection before downsizing — stiffness falls much faster than weight.
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