Sheet metal plays a big role in modern life. From car bodies to kitchen appliances and roofing to ductwork, it’s everywhere. But one of the most important things to understand when working with sheet metal is its thickness. Why? Because the thickness of a metal sheet affects how strong it is, how flexible it can be, and what kind of jobs it’s suitable for.
This guide will help you understand everything about sheet metal thickness, how it’s measured, and why it matters. Whether you’re a student, dyer, or professional
Steel fabricator, you’ll find clear answers here.
What is Sheet Metal Thickness?
Sheet metal thickness refers to how thick or thin a metal sheet is. It’s a key factor when choosing metal for a job.
There are two common ways to measure thickness:
- Gauge (G): A non-linear number system mostly used in the U.S.
- Millimeters (mm): A metric measurement used worldwide.
For example, a thinner metal has a higher gauge number (like 26 gauge), while a thicker metal has a lower gauge number (like 10 gauge). This may seem confusing, but we’ll break it down.
Why Thickness Matters in Sheet Metal Work
The thickness of sheet metal affects:
- Strength: Thicker metal can carry more weight and resist pressure.
- Flexibility: Thinner sheets bend easier but aren’t as strong.
- Cost: Thicker metals are more expensive.
- Workability: Thin sheets are easier to cut and shape.
If you’re building a rooftop or covering machinery, you’d likely want a thicker sheet. For crafting or decorative items, a thinner one might do the trick.
Different Types of Sheet Metals
There are various sheet metals, each with different thickness standards and uses:
1. Steel Sheets
Strong and widely used in construction and automotive.
2. Aluminum Sheets
Lightweight and corrosion resistant, ideal for outdoor and aerospace use.
3. Copper Sheets
Great conductor of electricity and heat, often used in electronics.
4. Sheet MS (Mild Steel)
Very common and affordable. Ideal for general fabrication and structural work.
Understanding Steel Sheet Thickness
When people mention steel sheet thickness, they usually refer to cold rolled or hot rolled steel. Common thicknesses range from 0.5 mm to 6 mm, depending on the purpose. Thin steel sheets are used for ducting and household items, while thicker sheets are used in vehicles and buildings.
Gauge System in Sheet Metal Explained
The gauge system measures thickness with numbers but higher numbers mean thinner metal. Strange? Yes, but it’s historical.
| Gauge |
Thickness (mm) |
Material |
| 10 |
3.42 mm |
Steel |
| 12 |
2.68 mm |
Steel |
| 16 |
1.52 mm |
Steel |
| 18 |
1.21 mm |
Steel |
| 22 |
0.76 mm |
Steel |
So if you’re wondering about 18 gauge in mm, it’s approximately 1.21 millimeters thick.
Gauge to Millimeter Conversion (with Chart)
Here’s a quick gauge to mm conversion chart for steel sheet metal thickness:
| Gauge |
Thickness (mm) |
| 10G |
3.42 mm |
| 12G |
2.68 mm |
| 14G |
1.90 mm |
| 16G |
1.52 mm |
| 18G |
1.21 mm |
| 20G |
0.91 mm |
| 22G |
0.76 mm |
This makes it easier to compare gauge numbers with actual millimeter values.
Popular Steel Sheet Metal Thicknesses
Depending on the industry, different thicknesses are used:
- Automotive: 18G to 20G (1.2 mm to 0.9 mm)
- Home Appliances: 22G to 24G (0.76 mm to 0.60 mm)
- Roofing and Cladding: 26G to 28G
- Construction and Beams: 10G to 14G
What is Sheet MS?
Sheet MS stands for Mild Steel Sheet. It’s made from low carbon steel and is one of the most affordable and versatile types of sheet metal.
Features of Sheet MS:
- Easy to weld and form
- Suitable for bending and shaping
- Common thickness ranges from 0.5 mm to 3 mm
Sheet MS is ideal for making furniture, panels, grills, frames, and more.
Applications of Various Sheet Thicknesses
Here’s how different thicknesses are used:
| Thickness (mm) |
Application |
| < 1 mm |
Ducts, packaging, electronics |
| 1–2 mm |
Body panels, casings, signs |
| 2–4 mm |
Structural frames, machinery |
| > 4 mm |
Heavy-duty industrial use |
Choosing the Right Sheet Thickness
When picking a sheet thickness, consider:
- Load and strength requirements
- Weather conditions
- Ease of cutting and bending
- Cost and availability
Always consult a gauge chart and match the metal to your project’s needs.
Tools to Measure Sheet Metal Thickness
Accurate measurements help avoid costly mistakes. Common tools include:
- Digital calipers
- Micrometers
- Gauge tools
- Ultrasonic thickness testers
Buying Guide for Steel Sheet Metal
Before buying steel sheet metal:
- Check thickness in both gauge and mm
- Ask for a material test certificate (MTC)
- Check if it’s cold-rolled or hot-rolled
- Look at finish, strength, and corrosion resistance
Safety Tips When Handling Metal Sheets
Working with metal can be risky if not handled properly:
- Wear gloves and safety glasses
- Use protective clothing
- Handle edges carefully (they can be razor sharp)
- Secure the sheet while cutting or welding
Maintaining and Storing Steel Sheets
- Keep sheets in a dry, cool place
- Use anti-rust sprays for MS sheets
- Avoid contact with moisture and chemicals
- Store flat to prevent bending
Conclusion
Understanding sheet metal thickness is vital for safe, efficient, and effective metalworking. Whether you’re comparing steel sheet thickness, converting 18 gauge in mm, or buying sheet MS, knowing the right thickness can make or break your project. For all your sheet metal solutions, trust the precision and expertise of
AtoZ Fabrication Pvt, Ltd. Be sure to use a gauge chart, consult professionals if needed, and always handle sheets with care.
Common FAQs About Sheet Metal Thickness
What is 18 gauge in mm?
18 gauge in steel sheet thickness is about 1.21 mm.
Is lower gauge steel thicker?
Yes. Lower gauge numbers mean thicker sheets.
What is sheet MS?
It’s Mild Steel Sheet, known for its low cost and good weldability.
How do I choose the right thickness?
Base it on application, strength needed, and material type.
Is 1 mm steel strong enough for construction?
Not for structural support, but okay for cladding and covers.
How can I measure sheet thickness at home?
Use a caliper or thickness gauge for accuracy.
