Sheet Metal Gauge Chart & Thickness Guide

Sheet Metal Gauge Chart

Complete steel gauge thickness chart and stainless steel gauge chart with aluminum and galvanized references. Gauge numbers are counterintuitive — a higher gauge means thinner material. This chart gives you the exact thickness in both inches and millimeters.

A sheet metal gauge chart is a reference table that converts gauge numbers to exact thickness measurements in inches or millimeters. The gauge system is an industry-standard method for specifying sheet metal thickness, where a higher gauge number indicates thinner material. Different materials — steel, stainless steel, aluminum, and galvanized — use different gauge standards, so the same gauge number yields different thicknesses depending on the material.

Steel Gauge Thickness Chart vs. Stainless Steel Gauge Chart

Sheet metal thickness varies by material even at the same gauge number. The steel gauge thickness chart above uses Manufacturer’s Standard Gauge (MSG), while the stainless steel gauge thickness chart follows its own standard, and the aluminum column uses the Brown & Sharpe (B&S) gauge system. A 14-gauge sheet of steel (0.0747") is not the same thickness as 14-gauge aluminum (0.0641"). Always confirm the correct standard for your material when specifying gauge.

This page also serves as a sheet metal gauge conversion chart — use the “Show mm” toggle to convert all values between inches and millimeters. For CNC machining and precision fabrication work, specifying thickness in decimal inches or millimeters is preferred over gauge numbers to avoid confusion between standards. Once you know the gauge thickness, you can calculate the bend allowance for your sheet metal part.

Common gauge ranges by application: 7–10 gauge (0.1345"–0.1793") for structural plates, trailer floors, and heavy equipment. 11–14 gauge (0.0747"–0.1196") for automotive body panels, appliance housings, and machine guards. 16–20 gauge (0.0359"–0.0598") for HVAC ductwork, electrical enclosures, and general fabrication. 22–30 gauge (0.0120"–0.0299") for roofing, flashing, and decorative trim.

Keep in mind that gauge is a nominal dimension. Actual sheet thickness varies within the tolerances allowed by the governing standard. For critical-fit applications, always verify measured thickness against your tolerance requirements rather than relying solely on gauge designation.

Note on sources: This chart shows nominal gauge thicknesses. Actual sheet thickness varies within the tolerances allowed by the governing standard (typically ±0.002"–0.005"). Verify measured thickness for critical-fit applications. Steel (MSG) and galvanized values are from Machinery’s Handbook, 29th Ed., pp. 2608–2612. Stainless steel nominal values follow the standard fractional-inch gauge system and have been cross-checked against DASMA TDS #154 (which lists ASTM minimums) and multiple industry suppliers. Aluminum values follow the Brown & Sharpe (B&S) gauge system.

How to Use This Chart

Use the material dropdown to show only the gauge standard relevant to your project. Click any column header to sort ascending or descending. Click a row to highlight it for easy reference when switching between this chart and your CAD model or drawing. The unit toggle switches between inches and millimeters. Click any thickness value to copy it to your clipboard. Use the Print button or Ctrl+P (Cmd+P on Mac) to print a clean, ink-friendly version of the chart.

If you're sending parts out for fabrication or laser cutting, always call out the decimal thickness on your drawing rather than just the gauge number. This prevents mix-ups between gauge standards and ensures your parts come back at the correct thickness. For bending operations, use our press brake tonnage calculator to determine the force needed for your gauge and material.

Example: Specifying Gauge on a Drawing

You need to order 16-gauge stainless steel for an electrical enclosure. From the chart above, 16-gauge stainless steel is 0.0625" (1.59 mm). On your drawing, call out “16 ga (0.0625")” as the material thickness and list “16 gauge stainless steel, ASTM A240 Type 304” in the material note. The decimal in parentheses is a reference dimension — it tells the fabricator what thickness to expect without implying a four-decimal-place tolerance.

If the enclosure will be bent, use the 0.0625" value to calculate your bend allowance and flat pattern layout. For heavier structural brackets on the same project, 14-gauge stainless (0.0781") or 12-gauge (0.1094") would be more appropriate — check the press brake tonnage calculator to confirm your brake can handle the thicker material.

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Frequently Asked Questions

Related Calculators

• Metal Weight Calculator — Calculate weight for sheet metal, plate, round bar, tube, and I-beam by material and dimensions
• Bend Allowance Calculator — Calculate flat pattern dimensions for sheet metal bending
• Press Brake Tonnage Calculator — Determine required press brake force for your material and bend
• K-Factor Calculator — Find the K-factor for accurate sheet metal flat pattern development
• Punch Force Calculator — Calculate the force required to punch holes in sheet metal

References

• Oberg, E. et al. Machinery’s Handbook, 29th Edition, Industrial Press, 2012, pp. 2608–2612. Steel (MSG) and galvanized nominal values.
• DASMA TDS #154 — Metal Gauge Chart, rev. 2010. Stainless steel and aluminum minimum thicknesses per ASTM A568/A924; used to cross-check nominal values.
• ASTM A480/A480M — Standard Specification for General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel Plate, Sheet, and Strip.

Data last verified: March 2026

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