PC Case Form Factors Explained - Everything You Need to Know!

When it comes to selecting the perfect components for your dream gaming PC, it can seem a little daunting. Especially when you have to consider the size of your hardware, not just the type of hardware you need.  But fear not – that’s where our team of PC experts at Overclockers UK comes in! We’ve compiled this handy guide to everything you need to know about different PC case form factors. So, sit back, grab a brew, some biscuits, and let’s get to it.  

PC Case Form Factors Explained - Everything You Need to Know!

What is a PC Case?

A basic definition of a PC case, otherwise known as a computer chassis, is what holds and protects all of your important hardware.  For many gamers, what case they choose is equally as important as the hardware inside it. How else can you show off all your latest gaming tech, stunning RGB lighting, or custom water-cooling loop? 

PC cases come with a plethora of stylish features, such as tempered glass panels, hinged or screw doors, noise-dampening, and LED lighting, and are constructed from a variety of different materials. Along with all of this, PC cases come in a variety of different sizes to suit everyone. 

PC Case Sizes Uncovered

The most common PC case form factors are: 

  • Mini-ITX  
  • Micro-ATX  
  • Mid Tower  
  • Full Tower  


Kolink Rocket Heavy Mini-ITX PC Case

Mini-ITX cases are the ideal choice for those looking to create a space-saving SFF (small form factor) PC but still take advantage of powerful gaming hardware. Mini-ITX cases are typically lightweight and are often a low-cost option for those on a budget, but still feature a whole host of unique features such as RGB lighting or tempered glass panels.  

Mini-ITX cases are often compatible with corresponding Mini-ITX motherboards, however, to guarantee full compatibility we recommend that you check the case specification or the manufacturer’s website.  


Similar to Mini-ITX, Micro-ATX cases are perfect for creating a compact SFF gaming PC without compromising on hardware. With a Micro-ATX case, you can build your very own powerful gaming PC that doesn’t take up too much room on your desk.  

The main difference between these two PC case sizes is the additional space in a Micro-ATX. You can utilise this extra wiggle room for more complex cooling configurations, such as water cooling, and larger graphics cards.  

Lian Li Lancool 205M PC Case

Micro-ATX cases are typically compatible with both Mini-ITX and Micro-ATX motherboards, however, it is recommended that you consult the case specification or manufacturer.  

Mid Tower:

Kolink Observatory HF Mid Tower PC Case

Mid Tower cases can usually support all your full-sized components, such as ATX motherboards, large power supplies, and even horizontal or vertical GPU layouts. The extra space that a Mid Tower case boasts means you can take advantage of large comprehensive cooling solutions, such as AiO custom water cooling or multiple fans.  

In addition to this, Mid Tower cases also come with plenty of must-have aesthetic features such as tempered glass panels, unique designs, and RGB lighting.  

A Mid-Tower case will typically fit ATX, Micro-ATX, and Mini-ITX motherboards, with some models even supporting up to E-ATX. To ensure full compatibility, be sure to check your case specification or the manufacturer’s website.  

Full Tower:

 Often measuring 22 inches x 10 inches, Full Tower cases can support up to the largest standard of motherboard and offer support for plenty of unique customisations, including complex water cooling, vertical or horizontal GPU layouts, tempered glass side panels, and RGB lighting.  

Phanteks NV7-D Full Tower PC Case

Full Tower PC cases are often compatible with E-ATX, ATX, Micro-ATX, and Mini-ITX motherboards. However, we recommend that you check the case specification or the manufacturer’s website.  

Alternative PC Case Size Options:

For those looking to create a home theatre or entertainment PC, there are also HTPC and Cube PC cases. 


Streacom ST-FC9S HTPC Case

Designed to be used as entertainment systems, Home Theatre PC cases (HPTC), harness all the power of a PC but with sleek, attractive aesthetics that will fit effortlessly into your living room.

HTPC cases will usually fit only, mini-ITX motherboards. However, to guarantee your hardware is compatible, you are advised to check the case specifications or the manufacturer’s website.


Utilise the sleek, modern aesthetics of a cube PC case, to design a system that is packed with powerful gaming hardware, that can be used as a portable LAN PC.  Whilst these cases may have a small form factor, they still support comprehensive cooling, larger GPUs, and PSUs, along with stylish features, such as tempered glass side panels. 

Cube cases can typically fit:

  • Mini-ITX
  • Micro-ATX

To ensure your hardware is compatible with the size of your case, it’s recommended that you consult the case specifications or the manufacturer’s website.

Kolink Satellite Micro-ATX Cube Case

So… What’s the Difference Between the PC Case Sizes

There are standard specifications for case form factors, however, our handy table can be applied to the majority of PC case sizes.  

Mini-ITXMicro-ATXMid TowerFull Tower
5.25” Bays11 to 22 to 53 to 6
3.5” Bays1 to 34 to 66 to 86 to 13
2.5” Bays0 to 40 to 40 to 100 to 11
Expansion Slots247 to 87 to 10
Graphics Cards11 to 22 to 33 to 4
Case Fans1 to 32 to 43 to 95 to 10

Upgrade Your PC Case 

Whether you want a space saving Mini-ITX or show stopping Full Tower, at Overclockers UK you can find a huge range of PC cases suitable for any type of set up.  We’ve included a few of our favourites below from each of the different form factors, however, if none of these suit your preferences or budget, you can shop all our PC cases by clicking the button below.  

Phanteks Eclipse P200 Air Mini-ITX Case: 

  • Mini-ITX form factor
  • Supports up to Mini-ITX motherboards
  • Vertical GPU support
  • Supports GPUs of up to 355mm in length
  • Removable fine dust mesh front panel

Kolink Citadel Mesh White aRGB Micro-ATX Case: 

  • Micro-ATX form factor
  • Supports Micro-ATX and Mini-ITX motherboards
  • Supports GPUs of up to 345mm in length
  • Full mesh front panel
  • Tempered glass side panel

Kolink Observatory Black RGB Mid Tower Case: 

  • Mid Tower form factor
  • Supports up to E-ATX motherboards
  • Tempered glass front and side panel
  • Supports GPPUs of up to 380mm in length

Lian Li O11 Dynamic XL Black Full Tower Case: 

  • Full Tower form factor
  • Supports up to E-ATX motherboards
  • Dual-chamber design
  • Supports GPUs of up to 446mm in length
  • Front and side tempered glass side panel

Read More From Our ‘Form Factors Explained’ Series

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28 days ago
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