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How thick is 26 gauge 钣金? In standard steel, 26 gauge is 0.0179 inches (0.455 mm). In aluminum, the same gauge number gives a thinner sheet at 0.0159 inches (0.404 mm). The difference exists because steel and aluminum follow separate gauge standards, and this is where most ordering mistakes begin.
A sheet metal gauge chart converts gauge numbers into actual thickness values in inches and millimeters. This guide covers every gauge from 10 to 30 for steel, stainless steel, aluminum and galvanized steel, explains why the same gauge means different thicknesses across metals, and shows how to specify sheet metal correctly on engineering drawings.
Sheet metal gauge is a numbering system that indicates the thickness of a metal sheet. A lower gauge number means a thicker sheet. A higher gauge number means a thinner sheet. This inverse relationship trips up buyers and engineers who encounter the system for the first time.
Gauge systems developed historically across metal manufacturing and wire production. Modern gauge numbers are references to published material-specific thickness tables, not a direct measurement or a reliable count of rolling passes.
There is no single universal gauge standard. Steel uses the Manufacturers’ Standard Gauge (MSG), which is based on the weight of the sheet per square foot. Aluminum and non-ferrous metals use the Brown and Sharpe gauge, also called the American Wire Gauge (AWG).
Stainless steel follows a separate scale that closely resembles, but does not match, the steel MSG values. Because each metal has its own gauge system, 16 gauge steel is not the same thickness as 16 gauge aluminum.
This is why specifying gauge alone on a drawing without naming the material is a reliable way to get the wrong part. More on that below.
The sheet metal gauge chart below compares nominal thicknesses from 10 to 30 gauge for standard steel, stainless steel, aluminum and galvanized steel. Each cell shows inches / millimeters, making material-to-material differences easier to check.
| Gauge | Steel (in / mm) | Stainless (in / mm) | Aluminum (in / mm) | Galvanized (in / mm) |
|---|---|---|---|---|
| 10 | 0.1345 / 3.416 | 0.1406 / 3.571 | 0.1019 / 2.588 | 0.1382 / 3.510 |
| 11 | 0.1196 / 3.038 | 0.1250 / 3.175 | 0.0907 / 2.304 | 0.1233 / 3.132 |
| 12 | 0.1046 / 2.657 | 0.1094 / 2.779 | 0.0808 / 2.053 | 0.1084 / 2.753 |
| 13 | 0.0897 / 2.278 | 0.0938 / 2.381 | 0.0720 / 1.829 | 0.0934 / 2.372 |
| 14 | 0.0747 / 1.897 | 0.0781 / 1.984 | 0.0641 / 1.628 | 0.0785 / 1.994 |
| 15 | 0.0673 / 1.709 | 0.0703 / 1.786 | 0.0571 / 1.450 | 0.0710 / 1.803 |
| 16 | 0.0598 / 1.519 | 0.0625 / 1.588 | 0.0508 / 1.290 | 0.0635 / 1.613 |
| 17 | 0.0538 / 1.367 | 0.0563 / 1.429 | 0.0453 / 1.151 | 0.0575 / 1.461 |
| 18 | 0.0478 / 1.214 | 0.0500 / 1.270 | 0.0403 / 1.024 | 0.0516 / 1.311 |
| 19 | 0.0418 / 1.062 | 0.0438 / 1.111 | 0.0359 / 0.912 | 0.0456 / 1.158 |
| 20 | 0.0359 / 0.912 | 0.0375 / 0.953 | 0.0320 / 0.813 | 0.0396 / 1.006 |
| 21 | 0.0329 / 0.836 | 0.0344 / 0.874 | 0.0285 / 0.724 | 0.0366 / 0.930 |
| 22 | 0.0299 / 0.759 | 0.0313 / 0.794 | 0.0253 / 0.643 | 0.0336 / 0.853 |
| 23 | 0.0269 / 0.683 | 0.0281 / 0.714 | 0.0226 / 0.574 | 0.0306 / 0.777 |
| 24 | 0.0239 / 0.607 | 0.0250 / 0.635 | 0.0201 / 0.511 | 0.0276 / 0.701 |
| 25 | 0.0209 / 0.531 | 0.0219 / 0.556 | 0.0179 / 0.455 | 0.0247 / 0.627 |
| 26 | 0.0179 / 0.455 | 0.0188 / 0.477 | 0.0159 / 0.404 | 0.0217 / 0.551 |
| 27 | 0.0164 / 0.417 | 0.0172 / 0.437 | 0.0142 / 0.361 | 0.0202 / 0.513 |
| 28 | 0.0149 / 0.378 | 0.0156 / 0.396 | 0.0126 / 0.320 | 0.0187 / 0.475 |
| 29 | 0.0135 / 0.343 | 0.0141 / 0.358 | 0.0113 / 0.287 | 0.0172 / 0.437 |
| 30 | 0.0120 / 0.305 | 0.0125 / 0.318 | 0.0100 / 0.254 | 0.0157 / 0.399 |
These values are nominal. Actual thickness from the mill can vary by the tolerances covered later in this article.
Choose the material column first, then find the gauge number. Each value is shown as nominal inches / millimeters. For example, 26-gauge standard steel is 0.0179 in / 0.455 mm, while 26-gauge aluminum is 0.0159 in / 0.404 mm. These are reference thicknesses, not guaranteed measured dimensions.
Gauge conversion values are nominal reference values based on common industry sheet-gauge tables. Actual ordered thickness and tolerances must be verified against the supplier’s product specification and mill certificate. For steel, stainless steel and aluminum products, check the applicable ASTM material standard rather than assuming all materials share one gauge scale. This guide supports preliminary selection; the engineering drawing and purchase order control production requirements.
10 gauge steel is 0.1345 inches (3.416 mm). At this thickness, steel sheet weighs about 5.625 pounds per square foot. It is the heaviest gauge commonly available as sheet rather than plate and is used for structural brackets, heavy equipment guards, trailer beds and industrial flooring.
10 gauge stainless steel is slightly thicker at 0.1406 inches (3.571 mm). 10 gauge aluminum is noticeably thinner at 0.1019 inches (2.588 mm), though aluminum’s lower density means the weight per square foot is roughly one quarter that of steel at the same gauge.
对于 数控加工 和 激光切割, 10 gauge is near the upper end of what most shops consider sheet metal. Thicker stock is typically classified as plate and handled differently in fixturing, cutting speed and tooling.
12 gauge steel is 0.1046 inches (2.657 mm). This is a common choice for automotive body panels, appliance housings and general structural fabrication. It offers a good balance of strength and formability without the weight and cutting difficulty of 10 gauge.
12 gauge stainless steel measures 0.1094 inches (2.779 mm). 12 gauge aluminum is 0.0808 inches (2.053 mm).
A common question is whether 12 gauge steel is 1/8 inch thick. It is not. One eighth of an inch is 0.125 inches, which falls between 11 gauge (0.1196 inches) and 10 gauge (0.1345 inches). Specifying “1/8 inch” on a drawing and expecting 12 gauge will produce a mismatch.
14 gauge steel is 0.0747 inches (1.897 mm). It is one of the most widely used gauges in sheet metal fabrication, covering enclosures, brackets, HVAC ductwork, light structural components and furniture frames.
14 gauge stainless steel is 0.0781 inches (1.984 mm). 14 gauge aluminum is 0.0641 inches (1.628 mm).
Another frequent question: is 14 gauge steel 1/4 inch thick? No. A quarter inch is 0.250 inches, which is far thicker than 14 gauge. That thickness corresponds roughly to 3 gauge, which is plate territory. The confusion usually comes from mixing up fractions with decimal equivalents.
How thick is 16 gauge sheet metal? In steel, 16 gauge is 0.0598 inches (1.519 mm). In stainless steel, it is 0.0625 inches (1.588 mm). In aluminum, 16 gauge is 0.0508 inches (1.290 mm).
16 gauge is a workhorse thickness for sheet metal fabrication. It is thick enough for load-bearing parts like panels and chassis components but thin enough to bend and form on standard press brakes without specialty tooling. Most shops stock 16 gauge in cold-rolled steel, 304 stainless and 5052 or 6061 aluminum.
For tight bends, evaluate the minimum inside bend radius against material grade, temper, grain direction, tooling and bending method. A 16-gauge aluminum part is not automatically easier to bend than steel: 5052-H32 and 6061-T6, for example, behave differently.
18 gauge steel is 0.0478 inches (1.214 mm). Stainless steel at 18 gauge is 0.0500 inches (1.270 mm). Aluminum is 0.0403 inches (1.024 mm).
This is the most common gauge for architectural sheet metal, roofing accents, decorative panels, electrical enclosures and kitchen equipment. It bends easily, welds cleanly and laser-cuts quickly. Where weight matters more than structural strength, 18 gauge is often the default starting point.
20 gauge steel is 0.0359 inches (0.912 mm). Stainless steel at 20 gauge is 0.0375 inches (0.953 mm). Aluminum is 0.0320 inches (0.813 mm).
How thick is 20 gauge sheet metal in inches? Just over 1/32 of an inch for steel. At this thickness, steel sheet becomes flexible enough for ductwork, light covers, decorative trim and electronics housings. It is still strong enough to hold its shape in a formed part, but not suitable for load-bearing structure on its own.
26 gauge steel is 0.0179 inches (0.455 mm). It is a frequently searched sheet thickness and a common gauge for metal roofing panels, flashing, HVAC duct liner and lightweight enclosures.
26 gauge stainless steel is 0.0188 inches (0.477 mm). 26 gauge aluminum is 0.0159 inches (0.404 mm). Galvanized steel at 26 gauge is 0.0217 inches (0.551 mm), noticeably thicker because the galvanized gauge standard accounts for the zinc coating weight.
Is 26 gauge steel thick? No. It is thin enough to flex by hand and dent under moderate pressure. For reference, 26 gauge steel is a little over half the thickness of a credit card. It is appropriate for non-structural applications where light weight and low cost matter more than rigidity.
Is 26 gauge or 30 gauge thicker? 26 gauge is thicker. Lower gauge numbers always mean thicker material. The difference is 0.0179 inches (26 gauge) versus 0.0120 inches (30 gauge) in steel.
The gauge number is not a direct measurement. It is a reference to a standard that was originally tied to the weight and density of the specific metal.
Steel gauge (Manufacturers’ Standard Gauge) is defined by US federal law (15 USC 206) and is based on the weight of steel sheet per square foot. The standard assigns each gauge a specific weight in ounces, and the corresponding thickness falls out of the density. Since steel, stainless steel and galvanized steel have slightly different densities and coating weights, the same gauge number maps to slightly different thicknesses.
Aluminum sheet commonly uses a Brown & Sharpe-derived gauge scale rather than the steel sheet scale. The gauge-to-thickness relationship is defined by the relevant table; material density alone does not determine the conversion.
This is why ordering “16 gauge sheet metal” without specifying the material is a problem. 16 gauge steel is 0.0598 inches. 16 gauge aluminum is 0.0508 inches. That is a 15 percent difference in thickness, which changes bend allowance calculations, weight estimates and part stiffness.
The gauge chart gives nominal values. The sheet that arrives from the mill may not match those numbers exactly, for three reasons.
Actual sheet thickness can differ from nominal gauge values. Applicable limits depend on the ordered thickness, width, material grade, processing condition and relevant specification, such as ASTM A568 for certain steel sheet products. Check the actual tolerance table and mill certificate; do not assume a single universal range for all 16-gauge steel.
Galvanized steel runs thicker than bare steel at the same gauge because the gauge designation includes the zinc coating. A 26 gauge galvanized sheet (0.0217 inches) is measurably thicker than 26 gauge bare steel (0.0179 inches). If you strip the zinc, the base steel underneath is thinner than the chart number.
Surface treatments can change final part dimensions. With Type II anodizing, part growth depends on coating thickness and the proportion of oxide formed above and below the original surface. For tight-fitting features, specify dimensions and inspection requirements after finishing.
When tolerances matter, specify the thickness in decimal inches or millimeters on the drawing, not the gauge number. The gauge is a shorthand for ordering; the decimal is what the part actually needs to be.
For precision parts and CNC machined components, call out sheet metal thickness in decimal inches or millimeters with a tolerance. Gauge numbers are useful for purchasing raw material but ambiguous on a manufacturing drawing.
A clear callout looks like this: “Material: 304 Stainless Steel, 0.0625 in. (1.588 mm) nominal, per ASTM A240.” That removes all ambiguity about which gauge standard applies and tells the shop exactly what to measure with a micrometer.
If you must use gauge, always pair it with the material: “16 gauge 304 stainless steel.” Never write just “16 gauge” without the metal name. And always confirm the decimal equivalent with your supplier before production, because some suppliers reference slightly different gauge tables.
When requesting a quote from Tuowei, provide the material grade, nominal thickness in inches or millimeters, tolerance, finish and part drawing. Tuowei’s sheet metal fabrication and CNC machining teams can use those details to discuss manufacturability and quotation requirements.
Gauge selection depends on four factors: structural requirement, weight limit, formability and cost.
Thicker gauge stock costs more per square foot, takes longer to cut and bend, and requires heavier tooling. Thinner stock saves weight and cost but may need stiffening features like ribs, flanges or hems to hold its shape. The right gauge is the thinnest one that meets the structural and stiffness requirements of the part.
在 数控加工 and precision 钣金加工, gauge selection directly affects process planning.
Thickness affects cutting speed, edge quality and gas consumption, but actual results depend on laser power, metal grade, assist gas, nozzle setup and quality requirements. Confirm production rates with a qualified process plan instead of using universal inches-per-minute figures.
Minimum inside bend radius, bend allowance and K-factor depend on the alloy, temper, thickness, grain direction, tooling and forming process. Use material-specific guidance and trial bends for critical work. For example, 5052-H32 generally tolerates tighter bends than 6061-T6 at comparable thickness.
Thin gauges (24 to 30) are prone to burn-through, especially in steel. TIG welding with low amperage or pulse settings is standard for these thicknesses. Thicker gauges (10 to 14) may need joint preparation and multiple passes.
Incoming sheet thickness variation can affect formed and machined feature dimensions. Critical drawings should define the required finished dimensions, datum scheme and inspection method. Review how stock tolerance and fixturing affect the final part before production.
14 gauge is thicker. In steel, 14 gauge is 0.0747 inches (1.897 mm) and 18 gauge is 0.0478 inches (1.214 mm). The lower the gauge number, the thicker the material. This holds true for steel, stainless steel, aluminum and every other metal that uses the gauge system.
20 gauge steel is 0.0359 inches, which is just over 1/32 of an inch. 20 gauge stainless steel is 0.0375 inches and 20 gauge aluminum is 0.0320 inches. At this thickness, sheet metal bends and forms easily on standard equipment and is common in ductwork, light enclosures and decorative panels.
11 gauge steel is 0.1196 inches (3.038 mm). In stainless steel, 11 gauge is 0.1250 inches (3.175 mm), in aluminum it is 0.0907 inches (2.304 mm), and in galvanized steel it is 0.1233 inches (3.132 mm).
3/32 of an inch is 0.09375 inches. In steel, that falls between 13 gauge (0.0897 inches) and 12 gauge (0.1046 inches), closer to 13 gauge. In stainless steel, it sits between 13 gauge (0.0938 inches) and 12 gauge (0.1094 inches). No standard gauge matches 3/32 exactly, so specifying the thickness in decimal inches is more precise than trying to force it into a gauge number.
A higher gauge number means thinner sheet metal. 30 gauge (0.0120 inches in steel) is the thinnest in this chart, and 10 gauge (0.1345 inches) is the thickest. The inverse numbering convention comes from historical gauge systems, but modern thickness must be checked against the material-specific gauge chart.
26 gauge is thicker. In steel, 26 gauge is 0.0179 inches (0.455 mm) and 30 gauge is 0.0120 inches (0.305 mm). Both are thin enough for roofing and flashing, but 26 gauge is the more common choice for metal roofing panels because it holds its shape better and resists denting.
作者：安迪，图威精密制造工程师。. 安迪专攻数控加工、精密制造和生产工程领域，在从快速原型制作到大规模量产的整个项目过程中拥有丰富的实践经验。他与工程和制造团队紧密合作，共同评估材料、公差、加工工艺以及设计可制造性。 他的文章提供了实用且具有技术深度的见解，旨在帮助工程师和采购人员做出更明智的制造决策、优化生产效率，并确保零件质量的一致性。欢迎了解图威精密的数控加工和定制制造解决方案，为您的下一个项目提供支持。.
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