Non-Ferrous Materials & Aerospace

Aluminum Gauge Converter

The Light Metal Metric. Convert standard aluminum (B&S) gauge numbers to precise decimal thickness in inches and millimeters for high-performance fabrication.

Inches (Decimal)
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Millimeters (mm)
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Weight (lb/ft²)
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Aluminum Common Sizing

Sheet (Thin)18 - 24 Gauge
Auto Body Panels12 - 16 Gauge
Heavy Ducting10 - 14 Gauge

Thermal Expansion

Aluminum has a thermal expansion coefficient significantly higher than steel. When designing thin aluminum panels, designers must allow for growth in extreme temperature environments to prevent buckling.

The Precision of Lightweight Fabrication

In aerospace, marine engineering, and modern automotive design, aluminum is the material of choice due to its incredible strength-to-weight ratio and natural resistance to corrosion. However, the system for measuring its thickness—the **Brown & Sharpe (B&S)** or **AWG** gauge—is distinct from the steel gauge system. Understanding this difference is critical to avoid structural errors and assembly misfits in high-precision fabrication shops.

The Brown & Sharpe Standard

The **Brown & Sharpe** (also known as the American Wire Gauge) system was developed in the 1850s and utilizes an exponential formula. This means that as gauge numbers increase, thickness decreases geometrically rather than linearly. While this system is the industry standard for non-ferrous metals like aluminum and copper, modern engineering blueprints now prefer to specify decimal thickness (inches/mm) to eliminate any ambiguity between the different gauge standards.

Weight Advantages in Design

Aluminum is roughly 170 lbs per cubic foot, compared to steel at 490 lbs. This means an aluminum panel of the same thickness as steel will weigh only 35% as much. When using this converter, you will notice that even as the thickness increases, the **Weight (lb/ft²)** remains surprisingly low. This is why performance vehicles use thicker 0.080" (12 gauge) aluminum panels while maintaining a lower total weight than thin 0.040" steel counterparts.

Common Aluminum Gauge Reference (B&S)

Gauge (B&S) Inch Eq. MM Eq. Weight (lb/ft²)
12 Gauge 0.0808" 2.052 mm 1.140
16 Gauge 0.0508" 1.290 mm 0.717
20 Gauge 0.0320" 0.813 mm 0.452
24 Gauge 0.0201" 0.511 mm 0.284

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Frequently Asked Questions

What is the "Brown & Sharpe" Gauge?

Also known as AWG (American Wire Gauge), this system is commonly used for aluminum and copper sheet metal thickness. It is an exponential series from gauge 0000 to 40.

Is 16 gauge aluminum the same as 16 gauge steel?

No. Aluminum usually follows the B&S (AWG) standard where 16 gauge is 0.0508 inches. Steel follows the MSG standard where 16 gauge is 0.0598 inches.

Why use aluminum instead of steel?

Aluminum has approximately one-third the density of steel, providing a high strength-to-weight ratio ideal for flight, marine, and performance transit applications.