gauge to thickness Converter

Enter the gauge number and select the material into the calculator to determine the approximate sheet thickness in inches and millimeters.

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Gauge to Thickness Formula

The following relationships are used to convert gauge to thickness. Gauge itself is determined by a published material table, and the inch value can then be converted to millimeters.

T_{in} = f(G, M)

T_{mm} = T_{in} \times 25.4

Variables:

• T_in is the sheet thickness in inches
• T_mm is the sheet thickness in millimeters
• G is the gauge number
• M is the material type or gauge standard
• f(G, M) means the thickness is looked up from the appropriate gauge table for the selected material

To calculate gauge thickness, first look up the nominal thickness in inches for the selected gauge and material, then multiply that value by 25.4 to convert inches into millimeters.

What is Gauge to Thickness Conversion?

Gauge to thickness conversion is the process of translating a sheet metal gauge number into a physical thickness measurement. Gauge is a legacy sizing system commonly used for thin sheet and plate. The scale works backward, so a smaller gauge number represents a thicker sheet, while a larger gauge number represents a thinner sheet. The exact thickness also depends on the material standard being used, which is why 16 gauge carbon steel is not the same thickness as 16 gauge aluminum.

Unlike standard unit conversions, there is no single universal algebraic formula that converts gauge directly into inches or millimeters for every material. Instead, manufacturers and reference charts publish standard gauge tables. The converter above uses those common tables for carbon steel, galvanized steel, stainless steel, and aluminum, then reports the result in both inches and millimeters.

How to Calculate Gauge to Thickness?

The following steps outline how to calculate the thickness from a gauge number.

1. First, determine the gauge number of the sheet.
2. Next, determine the material or gauge standard being used, such as carbon steel, galvanized steel, stainless steel, or aluminum.
3. Then, look up the nominal thickness in inches from the appropriate gauge reference table.
4. Finally, convert the thickness to millimeters using the formula T_mm = T_in × 25.4.
5. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Gauge Number (G) = 16

Material (M) = Carbon Steel

Thickness in Inches (T_in) = 0.0598 in

Thickness in Millimeters (T_mm) = 1.519 mm

Gauge to Thickness Reference

This page shows how to convert a sheet metal gauge number into a physical thickness. Gauge is commonly used in fabrication, construction, HVAC, and manufacturing drawings. Because the system is based on material-specific reference tables instead of a linear scale, it is important to know both the gauge and the material before selecting stock or interpreting specifications.

• Carbon steel: US standard steel sheet gauge.
• Galvanized steel: similar scale but slightly thicker due to coating and reference standards.
• Stainless steel: close to but not identical to plain steel sheet gauge.
• Aluminum: common aluminum sheet gauge chart.

Once you know which material applies, converting gauge is straightforward. Choose the gauge number, read the nominal thickness from the reference chart, and convert that thickness from inches to millimeters if needed. The calculator automates this lookup for gauges 10 through 30.

Gauge to Thickness Conversion Table

The table below lists example thickness values for common gauges and materials. Values are nominal and based on widely used US gauge charts.

Real-world sheet may be slightly thicker or thinner than the nominal chart value because of manufacturing tolerance, coating thickness, and product specification. Even so, knowing the standard gauge-to-thickness relationship makes it much easier to compare drawings, choose stock, and translate between gauge, inches, and millimeters.