Sheet Metal / Material Reference

Sheet Metal Gauge Chart: Steel, Aluminum, and Stainless Thickness

What Is Sheet Metal Gauge?

The gauge system dates back to wire-drawing conventions from the 1800s, where the number corresponded to how many times the wire or sheet had been drawn through a die. More draws meant thinner material and a higher number. The name stuck even though modern sheet metal is rolled, not drawn.

For practical purposes, gauge tells you the approximate thickness of a sheet. But because the system was never unified across materials, “20 gauge steel” and “20 gauge aluminum” are not the same physical thickness. This distinction matters every time you call out a material on a drawing or place a purchase order.

When you send us a drawing, it’s helpful to include the decimal equivalent alongside the gauge call-out. That way, there’s no ambiguity about which standard you’re referencing. If you only list gauge without a decimal, we’ll confirm the intended thickness before cutting.

Higher Gauge = Thinner Material

Buyers new to sheet metal fabrication sometimes read “22 gauge” and assume it’s heavier stock than “16 gauge.” It’s the opposite. If your part needs structural rigidity, you generally want a lower gauge number. If you need a lightweight formed part, higher gauge gets you there.

This inverse relationship can cause real problems on drawings. We’ve seen purchase orders where the customer called out a gauge that was two steps lighter than the actual part required, simply because the numbers felt counterintuitive. When you’re designing for structural load or corrosion resistance, double-check your gauge against the actual decimal thickness for the material you’re specifying.

Gauge Is Material-Specific

This is the most important thing to know about gauge, and it catches people off guard even with years of fab experience. A purchasing manager who runs carbon steel jobs all day will sometimes pull up a steel gauge reference and apply it to an aluminum order. The result is parts that come out 15 to 25 percent thinner than intended.

The three major standards in use:

• Mild/carbon steel: Manufacturers Standard Gauge (MSG). This is the most common reference for hot-rolled and cold-rolled sheet.
• Stainless steel: Uses a fractional-inch system. Values are close to but not identical to the MSG carbon steel values.
• Aluminum: Brown and Sharpe (B&S) gauge, also called American Wire Gauge (AWG) when applied to sheet. Produces distinctly thinner values than steel at the same gauge number.

When you send us a drawing, calling out both the gauge and the decimal thickness removes all ambiguity. A note like “16ga / 0.0598” on carbon steel or “16ga / 0.0508” on aluminum tells us exactly what you need.

Gauge Thickness Reference Table

Look at 16 gauge: mild steel is 0.0598 inches, stainless is 0.0625 inches, and aluminum is 0.0508 inches. That’s a meaningful difference. If you’re designing a bracket and calling out 16ga without specifying the material-specific standard, you could end up with a part that’s 15 percent lighter or heavier than your design calls for.

For laser cutting, these thickness values also affect cut settings, assist gas pressure, and achievable edge quality. When our team programs a job, we’re working from confirmed decimal thickness, not just a gauge number. This is another reason to confirm both in your drawing.

Common Gauges by Application

Here’s how the gauge ranges break down in practice across the industries we serve:

• 7 to 10 gauge (0.135″+ on steel): Heavy equipment frames, structural members, agricultural equipment, mining components. This is plate territory in many shops, though it’s still technically sheet-range on the gauge scale.
• 11 to 14 gauge (0.075″ to 0.120″ on steel): General fabrication, industrial enclosures, machine guards, material-handling components. Good balance of strength and formability.
• 16 to 18 gauge (0.048″ to 0.060″ on steel): The most commonly ordered range for custom parts. HVAC ductwork, brackets, covers, panels, light frames. Works well on our laser cutting equipment and press brake forming.
• 20 gauge and lighter: Skins, housings, thin formed parts, decorative elements. Requires careful handling to avoid oil-canning and distortion during cutting and forming.

When a customer comes to us with a new part that doesn’t have a thickness specified yet, we often ask about the application and loading requirements before suggesting a gauge. A 16-gauge carbon steel bracket might be plenty for a light-duty shelf but inadequate for a part under cyclic load in agricultural equipment. The gauge you pick should match the structural need, not just the tradition of what you’ve ordered before.

Choosing the Right Thickness

A few practical considerations when settling on a gauge for a new part:

Formability. Thicker material requires more tonnage to bend and has a larger minimum bend radius. If your part has tight bends, going one gauge heavier might mean a different die setup or a risk of cracking. See our page on design for laser cutting and forming for more on minimum bend radius by material thickness.

Weight. Going from 16 gauge to 14 gauge on a panel adds roughly 25 percent more weight per square foot. If your assembly has a weight budget, gauge selection is one of the most direct levers you have.

Laser cutting limits. Thicker gauge cuts slower and may require more passes or higher assist gas pressure. For high-volume jobs on thick stock, discuss the gauge with our team early. It can affect lead time. For more on how thickness interacts with laser-cuttable material thicknesses, that page covers the detail by material and wattage.

Powder coating adhesion. Very light gauges (20+) can distort in the cure oven. Most standard sheet metal gauges in the 16 to 18 range go through our powder coating line without issue.