Mild Steel Angle Sizes – A Guide to Dimensions

But with various sizes available, how do you know which one is right for your project? In this guide, we’ll break down the different mild steel angle sizes, their applications and how to choose the perfect fit for your needs.

If you’re new to mild steel angle, read this article: What Is Mild Steel Angle? (Uses, Benefits & Properties)

Mild steel angle is measured by its leg lengths and thickness. For example, a 25mm x 25mm x 3mm mild steel angle has two equal sides of 25mm and a thickness of 3mm. The larger the dimensions, the stronger and more load-bearing the angle becomes.

Why Do Size and Weight Matter?

   
• Smaller sizes – Lightweight and ideal for general-purpose projects.
   
• Larger sizes – Provide greater strength and rigidity, making them perfect for load-bearing applications.
   
• Weight impacts handling and installation – Heavier angles may require extra support during installation compared to thinner angles due to being more difficult to lift and secure in place.

At The Metal Store, we offer a range of mild steel angle sizes to suit different needs. Here’s a breakdown of our available options:

1. Small Sizes – Lightweight Applications

These smaller angles are ideal for projects where weight and space are key considerations.

    ✅ 13mm x 13mm x 3mm (0.82 kg per 1.5m length)       
           
• Best for light-duty brackets, edging and small frames.
           
• Suitable for craft projects and decorative elements.
       
    ✅ 20mm x 20mm x 3mm (1.31 kg per 1.5m length)       
           
• Great for DIY furniture, shelving supports and basic reinforcements.
           
• Lightweight but still sturdy enough for small-scale structures.
       
   

2. Medium Sizes – General-Purpose Use

These angles offer a balance between strength and ease of handling, making them ideal for home and workshop projects.

    ✅ 25mm x 25mm x 3mm (1.66 kg per 1.5m length)       
           
• Commonly used for workshop benches, shelving units and vehicle modifications.
           
• Provides good stability without excessive weight.
       
    ✅ 30mm x 30mm x 3mm (2.02 kg per 1.5m length)       
           
• A step up in strength, ideal for frame reinforcements and general construction.
           
• Offers more load-bearing capacity while remaining easy to work with.
       
   

3. Large Sizes – Heavy-Duty Applications

Larger mild steel angles are built for structural reinforcement and industrial projects.

    ✅ 40mm x 40mm x 3mm (2.72 kg per 1.5m length)       
           
• Strong and rigid, used for load-bearing structures and industrial shelving.
           
• Ideal for security grilles, fencing and bracing elements.
       
    ✅ 50mm x 50mm x 3mm (3.43 kg per 1.5m length)       
           
• The strongest option, perfect for heavy-duty construction, security gates and structural supports.
           
• Provides maximum durability and stability for demanding applications.
       
   

Selecting the correct mild steel angle for your project depends on several factors:

1. Consider Your Application

Different projects require different sizes. Here’s a general guide:

   
• Small angles (13mm – 20mm) – Best for light-duty work like brackets, edging and decorative applications.
   
• Medium angles (25mm – 30mm) – Ideal for DIY furniture, shelving and reinforcement.
   
• Large angles (40mm – 50mm) – Used for heavy-duty construction, structural frames and load-bearing projects.

2. Load-Bearing Capacity

The thicker and wider the mild steel angle, the more weight it can support. If you're working on a structure that requires high strength (like scaffolding, framework or vehicle modifications), you’ll likely need a 40mm or 50mm angle for increased stability. For lighter applications, such as home projects and shelving, a 20mm or 25mm angle will more than likely do the job without unnecessary weight.

However, it’s important to remember that the load-bearing capacity of mild steel depends on various factors, such as:

   
• The grade of steel
   
• The size of your section
   
• Your method of fabrication
   
• The overall structural design

We strongly advise that you consult a qualified structural engineer or architect to assess your specific project requirements and check that you comply with relevant safety standards and building codes. The information we’ve provided is general in nature and shouldn’t be used as a substitute for professional engineering advice.

3. Cutting and Machining Considerations

Larger angles require more effort to cut, drill and weld. If you’re working with basic tools, you may find smaller sizes easier to handle. However, for industrial-scale projects, investing in heavier-duty cutting tools or pre-cut mild steel angles is recommended.

At The Metal Store, we offer unlimited free cutting on mild steel angles, so you can get precisely the size you need without extra work. Need drilling too? Just get in touch – we’ll see if we can help and provide a quote.

4. Finish & Coating Options

Mild steel angles are available in different finishes, each suited for various conditions:

   
• Untreated mild steel – Great for indoor use or applications where you plan to paint or coat the steel.
   
• Galvanised mild steel – Best for outdoor projects, as it is rust-resistant.
   
• Powder-coated steel – Offers aesthetic appeal while adding durability and corrosion protection. Is this something you’re after? We can give your metal the perfect finish with our powder-coated steel services.

If your project is exposed to moisture or extreme weather, go with a galvanised or powder-coated finish to prevent rust and prolong its lifespan.

Not sure what project to work on? Take a look at our recent article: 10 Ways to Use Mild Steel Angle in Your Next Project.