Last updated on February 2nd, 2026 at 02:40 pm
In addition to selecting the material itself, you need to pick the optimal thickness. The gauge that may instinctively look or feel right isn’t always the best option-there are many factors that go into choosing the right material thickness for sheet metal parts.
Not to worry! Our expert fabricators are here to help you determine which gauge is ideal for your next project.
Choosing the wrong sheet metal thickness can impact strength, fit, bend accuracy, cost, and lead time. Understanding how gauge works across different metals helps prevent tolerance issues, sourcing delays, and costly redesigns later in the fabrication process.
Table of Contents
- 1 Gauge Thickness Varies from Metal to Metal
- 2 Certain Material Gauges Can Be Difficult to Source
- 3 Approved Sheet Metal’s Standard In-Stock Material Thicknesses
- 4 Recommended Default Sheet Metal Tolerances
- 5 Metal Fabrication Material Thickness FAQ
- 5.0.1 How does gauge thickness vary across different materials in precision sheet metal fabrication?
- 5.0.2 What issues might arise if the precise material gauge isn’t considered in a design, particularly in components requiring a precise fit?
- 5.0.3 Are there challenges in sourcing specific material gauges for fabrication projects?
- 5.0.4 What does Approved Sheet Metal offer in terms of standard in-stock material thicknesses for aluminum, steel, and stainless steel fabrication?
- 5.0.5 How can I ensure the material gauge I need is readily available without causing delays in my fabrication project?
Gauge Thickness Varies from Metal to Metal
The gauge size of a piece of material tells you the thickness of the metal. What’s confusing is that the precise thickness of a gauge can vary slightly from one material to the next.
Gauge is not a universal measurement. The same gauge number represents different actual thicknesses depending on the metal type, which is why relying on gauge alone can be misleading.
A classic example is aluminum vs. stainless steel.
16 gauge is a common size for aluminum. So what would happen if you swapped 16 gauge aluminum for 16 gauge steel? Let’s take a look. . .
16 gauge aluminum is 0.062″ thick, whereas 16 gauge steel is actually 0.059″ thick. The 0.003″ difference in thickness may not seem significant, but depending on your design, that variation can cause big problems in your final product. For example, components that need to fit inside one another-such as a box with a cover-may not fit precisely enough, or at all, if the exact material thickness isn’t taken into account.
This is a common source of fit-up issues in enclosures, covers, and assemblies where parts must nest, overlap, or align precisely after forming.
The higher the gauge number, the thinner the material-and the more significant discrepancies in thickness become. That’s why it’s always important to check the thickness of the gauge for the material you want to use. Even tiny variations in thickness can lead to a tolerance stack-up and cause your part to malfunction.
Material thickness also affects bend radius, forming consistency, and how much variation accumulates across multiple bends, especially in precision assemblies.
Certain Material Gauges Can Be Difficult to Source
When choosing the gauge of your material, you may first want to consult with us to find out if that size is readily available. Requesting a material with an unusual thickness can add to your project’s lead time-and in many cases, an in-stock alternative will work just as well.
If we spot a particular material gauge in your design that we know will be difficult to source, we’ll always let you know right away. Often, designers are unaware that a certain thickness is uncommon and are pleased to learn that we can easily provide a comparable substitution. In these cases, we’ll work with you to update your model at no additional cost.
Of course, we’re happy to source specialty materials if you need them-we’ll always go the extra mile for our customers. We just like to be transparent that choosing a material in a non-standard gauge may increase your cost and lead time.
Also, keep in mind that just because a particular gauge size is technically available doesn’t mean your sheet metal fabrication shop will always have it in stock. When possible, use materials you are certain your manufacturer has on hand or can source quickly.
As a general rule, designing around standard, commonly stocked thicknesses gives you more flexibility, faster turnaround, and fewer surprises during quoting and production.
Approved Sheet Metal’s Standard In-Stock Material Thicknesses
To make life easier for our customers, we’re sharing the list below to clarify the standard material thicknesses we keep in stock for aluminum, steel, and stainless steel fabrication.
The table below reflects the material thicknesses we most commonly keep in stock for rapid prototyping and low-volume production. Using these thicknesses typically results in faster quotes and shorter lead times.
| Standard Sheet Sizes | Aluminum | CRS, Stainless Steel, Galvanneal and Galvanized |
|---|---|---|
| 48 x 40 | .020 | .018 |
| 120 x 48 | .032 | .024 |
| 120 x 60 | .040 | .030 |
| .050 | .036 | |
| .062 | .048 | |
| .080 | .059 | |
| .093 | .074 | |
| .100 | .089 | |
| .125 | .104 | |
| .190 | .119 | |
| .250 | .134 | |
| .179 | ||
| .250 | ||
| .375 |
If you have questions about material thickness, gauge selection, or how these choices affect cost and lead time, feel free to call or email us anytime. Even better, request a quote and let our team review your design before issues arise.
Recommended Default Sheet Metal Tolerances
| DIM | Tolerance (MM) | Tolerance (Inches) | Description |
| A | ± 0.13 | ± 0.005 | Sheared Edge to Hole |
| B | ± 0.13 | ± 0.005 | 2 Holes on One Surface |
| C | ± 0.25 | ± 0.010 | Formed Edge to Hole |
| D* | ± 0.76 | ± 0.030 | Holes Across 2 Bends |
| E* | ± 0.76 | ± 0.030 | Holes Across 4 Bends |
| F | ± 0.25 | ± 0.010 | Sheared Edge to Bend |
| G | ± 0.38 | ± 0.015 | Across 2 Bends |
| H* | ± 0.76 | ± 0.030 | Formed Part |
* Dimensions D, E and H are not recommended forms of dimensioning
These tolerances are recommended and best practices. We can obtain tighter tolerances (depending on part geometry/ construction), contact us for more information Download PDF
Metal Fabrication Material Thickness FAQ
How does gauge thickness vary across different materials in precision sheet metal fabrication?
Gauge size indicates metal thickness, but this can vary slightly between materials. For example, while 16-gauge aluminum measures 0.062″ thick, 16-gauge steel is actually 0.059″ thick. These small differences can significantly impact how parts fit together in a design.
What issues might arise if the precise material gauge isn’t considered in a design, particularly in components requiring a precise fit?
Even slight gauge variations can lead to tolerance stack-ups, causing components like boxes with covers to not fit precisely or even at all. It’s crucial to factor in the exact material thickness to avoid such issues.
Are there challenges in sourcing specific material gauges for fabrication projects?
Uncommon thicknesses may pose challenges in sourcing, potentially increasing lead times. Discussing material availability with the fabricator early on can help identify suitable alternatives readily available in stock, minimizing delays.
What does Approved Sheet Metal offer in terms of standard in-stock material thicknesses for aluminum, steel, and stainless steel fabrication?
For aluminum, steel (CRS, Galvanneal, Galvanized), and stainless steel, we maintain a range of standard sheet sizes with various thicknesses, ensuring readily available materials for fabrication projects.
How can I ensure the material gauge I need is readily available without causing delays in my fabrication project?
It’s advisable to consult with the fabrication shop to confirm the availability of the required material gauge. Opting for in-stock materials or those easily sourced by the manufacturer can prevent delays and additional costs in sourcing non-standard gauges.