Sheet Metal Gauge Chart

What Is Sheet Metal Gauge?

Sheet metal gauge is a numbering system used to describe sheet thickness. The important rule is that a higher gauge number means a thinner sheet. For example, 10 gauge steel is thicker than 18 gauge steel, and 18 gauge steel is thicker than 20 gauge steel.

Gauge is also material-specific. Mild steel, stainless steel, and aluminum use different thickness standards, so the same gauge number does not always mean the same thickness. For example, 18 gauge mild steel is 0.0478" thick, 18 gauge stainless steel is 0.0500" thick, and 18 gauge aluminum is 0.0403" thick.

Use the chart below to convert gauge to inches or millimeters by material. If you are choosing between steel and stainless, our mild steel vs stainless steel guide covers the tradeoffs beyond thickness.

Sheet Metal Gauge Chart

Use this sheet metal gauge chart to compare nominal aluminum, mild steel, and stainless steel gauge thicknesses. Gauge values are reference conversions, so use the stocked material notes below the chart when designing parts for Fabworks.

If you plan to order sheet metal parts from Fabworks, design around stocked material thicknesses when possible. Stocked material keeps lead times shorter and makes quoting more predictable. For material-specific options, start with our sheet aluminum, sheet steel, and sheet stainless steel pages.

For 1008 steel, Fabworks stocks 0.048" (1.22 mm), 0.059" (1.50 mm), 0.074" (1.88 mm), 0.104" (2.64 mm), 0.119" (3.02 mm), 0.135" (3.43 mm), and 0.187" (4.75 mm). These are the actual stocked thicknesses to use for Fabworks designs and quotes.

Common Gauge Thicknesses

These are the gauge conversions people look up most often for mild steel. Stainless and aluminum are shown in the chart above because their thicknesses differ.

How Thick Is 10 Gauge Steel?

10 gauge mild steel is 0.1345 inches (3.42 mm) thick as a nominal gauge reference. Fabworks stocks 1008 steel near 10 gauge at 0.135 inches (3.43 mm). In stainless steel, 10 gauge is 0.1406 inches (3.57 mm). In aluminum, 10 gauge is 0.1019 inches (2.59 mm). It is a heavy gauge for structural brackets, mounts, frames, and parts that need high rigidity.

How Thick Is 11 Gauge Steel?

11 gauge mild steel is 0.1196 inches (3.04 mm) thick as a nominal gauge reference. Fabworks stocks 1008 steel near 11 gauge at 0.119 inches (3.02 mm). In stainless steel, 11 gauge is 0.1250 inches (3.18 mm). In aluminum, 11 gauge is 0.0907 inches (2.30 mm). It is useful when you need strength close to 10 gauge with slightly lower weight.

How Thick Is 12 Gauge Steel?

12 gauge mild steel is 0.1046 inches (2.66 mm) thick as a nominal gauge reference. Fabworks stocks 1008 steel near 12 gauge at 0.104 inches (2.64 mm). In stainless steel, 12 gauge is 0.1094 inches (2.78 mm). In aluminum, 12 gauge is 0.0808 inches (2.05 mm). It is a common choice for enclosures, brackets, and structural parts.

How Thick Is 14 Gauge Steel?

14 gauge mild steel is 0.0747 inches (1.90 mm) thick as a nominal gauge reference. Fabworks stocks 1008 steel near 14 gauge at 0.074 inches (1.88 mm). In stainless steel, 14 gauge is 0.0781 inches (1.98 mm). In aluminum, 14 gauge is 0.0641 inches (1.63 mm). It is one of the most common gauges for laser-cut sheet metal parts because it balances strength, bendability, and cost.

How Thick Is 16 Gauge Steel?

16 gauge mild steel is 0.0598 inches (1.52 mm) thick as a nominal gauge reference. Fabworks stocks 1008 steel near 16 gauge at 0.059 inches (1.50 mm). In stainless steel, 16 gauge is 0.0625 inches (1.59 mm). In aluminum, 16 gauge is 0.0508 inches (1.29 mm). It works well for panels, covers, enclosures, and parts that need moderate stiffness.

How Thick Is 18 Gauge Steel?

18 gauge mild steel is 0.0478 inches (1.21 mm) thick as a nominal gauge reference. Fabworks stocks 1008 steel near 18 gauge at 0.048 inches (1.22 mm). In stainless steel, 18 gauge is 0.0500 inches (1.27 mm). In aluminum, 18 gauge is 0.0403 inches (1.02 mm). It is lightweight, easy to bend, and common for covers, electronics enclosures, and light-duty brackets.

How Thick Is 20 Gauge Steel?

20 gauge mild steel is 0.0359 inches (0.91 mm) thick. In stainless steel, 20 gauge is 0.0375 inches (0.95 mm). In aluminum, 20 gauge is 0.0320 inches (0.81 mm). It is best for light covers, decorative panels, and parts where low weight matters more than rigidity.

How Thick Is 22 Gauge Steel?

22 gauge mild steel is 0.0299 inches (0.76 mm) thick. In stainless steel, 22 gauge is 0.0313 inches (0.79 mm). In aluminum, 22 gauge is 0.0253 inches (0.64 mm). It is a thin sheet metal gauge used for lightweight covers, fixtures, and decorative sheet parts.

Which Sheet Metal Gauge Should I Use?

The right sheet metal gauge depends on strength, stiffness, weight, bendability, and available material. As a starting point:

• 7-10 gauge: heavy structural parts, frames, thick mounting plates, and parts that need high stiffness.
• 11-14 gauge: general fabrication, enclosures, brackets, and parts that need a strong but still workable sheet thickness.
• 16-18 gauge: common laser-cut sheet metal parts, covers, panels, and light-duty brackets.
• 20-24 gauge: lightweight housings, interior panels, decorative parts, and thin covers.
• 26-30 gauge: very thin sheet metal, flashing, shims, and non-structural covers.

When in doubt, 16 or 18 gauge is a good starting point for many custom sheet metal parts. If the part carries load, takes impact, or needs to resist flexing, move thicker. If weight is more important than stiffness, move thinner.

What to Consider When Choosing Gauge

• Strength: Lower gauge numbers are thicker and resist deflection better.
• Weight: Thinner gauges reduce part weight but can flex more.
• Bendability: Thick material needs more bending force and larger bend radii.
• Cost: Thicker sheets cost more and can take longer to cut.
• Material: Steel, aluminum, and stainless steel have different stiffness, corrosion resistance, and gauge thicknesses.
• Stock availability: Designing around stocked sheet thicknesses can reduce cost and lead time.

If you are designing a part that will be bent, also review our sheet metal bending guidelines before finalizing your thickness.

Frequently Asked Questions

Does a higher gauge number mean thicker or thinner sheet metal?

A higher gauge number means thinner sheet metal. Gauge numbers run in reverse: 10 gauge is thicker than 14 gauge, 14 gauge is thicker than 18 gauge, and 18 gauge is thicker than 20 gauge.

Why is 18 gauge steel different from 18 gauge aluminum?

Gauge standards are material-specific. The same gauge number can convert to different physical thicknesses depending on whether the material is mild steel, stainless steel, or aluminum.

What gauge is most common for laser-cut sheet metal parts?

14, 16, and 18 gauge are common for custom laser-cut sheet metal parts. 14 gauge is stronger, 16 gauge is a balanced middle option, and 18 gauge is lighter and easier to bend.

How do I convert sheet metal gauge to inches or millimeters?

Use a material-specific gauge chart. Find the gauge number in the first column, then read the thickness for the correct material in inches or millimeters. Do not use a steel gauge chart for aluminum or stainless steel.

Is 18 gauge thicker than 20 gauge?

Yes. 18 gauge is thicker than 20 gauge. For mild steel, 18 gauge is 0.0478 inches (1.21 mm), while 20 gauge is 0.0359 inches (0.91 mm).