When you’re building a new computer, one of the first things that you’re going to have to determine is how large it’s going to be.
The size of your computer case can affect everything ranging from the parts that you can fit inside of it to how portable it will be if you ever want to travel.
There are a few different case sizes, ranging from mini-ITX at the smallest range of the spectrum all the way up to EATX.
These form factors are determined by the kind of motherboard that fits into the case, and the case sizes are actually named after the motherboard varieties that fit into them.
However, keep in mind that smaller isn’t always better, as it will give you less room to build in and it will make it harder for air to flow through the machine.
Without delaying any further, let’s start with the smallest kind of case and work our way up to the largest one.
Computer Case Sizes
Mini-ITX / Small Form Factor
The smallest kind of case is the mini-ITX variety, and these are also referred to as SFF (small form factor cases).
The SFF case is designed to be as portable as possible while still allowing you to fit in a reasonable number of components, though some of them won’t have room for an expansion card.
These “console killer” builds will often combine the versatility of a PC with the size and convenience of a console so that you can bring them anywhere, especially on vacation and to LAN parties.
Micro ATX / Mini Tower
If a mini-ITX case sounds a little too intimidating because of the small size, you have an option between it and a more traditional tower.
The MicroATX motherboard can fit into most standard ATX towers, but recently there have been more and more mini towers popping up.
These cases are usually a little bit shorter than the usual mid towers that people are used to dealing with, and this will often make them a more affordable choice.
If you decide to go for a micro ATX build then check out our Top 10 Micro ATX Cases.
ATX / Mid Tower
Up next, we’re going to cover the most common form factor: ATX.
Motherboards of this type will usually fit into mid towers, and these are the kind of computer cases that you’ll find on most PCs.
These cases are relatively large, and they often feature a lot of empty space.
This extra room means that it’s a lot easier to build in an ATX case, but the larger motherboard may be a little complicated for a first-timer, especially when trying to set RAM to dual-channel mode.
Related: single vs dual vs quad channel RAM
EATX / Full Tower
The final kind of case that we’ll go over is the EATX form factor, which is also known as a full tower.
These computers are far larger than most, and they’re designed to contain many more components, ranging anywhere from additional fans to an entire second motherboard.
Full towers that can fit two motherboards can often contain two separate systems. This makes them ideal for server setups or streamers who want to be able to play at the same time.
Since these cases are so spacious, they’ll also feature superior airflow when compared to the smaller sizes.
Of course, since the case has so much more volume, you’ll need to invest in more fans that can push a larger amount of air through the case.
In addition, you can load so many components into one of these cases, you’ll have to keep a close eye on your temperatures, particularly if your cooling setup isn’t that powerful.
An EATX motherboard can often support more DIMM slots than a standard ATX model. Also, some of them even come with a slot for a second processor. If you’re planning on using a big air CPU cooler, then the largest ones will be able to fit into a full tower without any trouble.
Keep in mind that massive machines like these aren’t often ideal for gamers unless they plan on streaming at the same time.
Most of the time, full tower cases are used for workstations and other powerful computers that are used in industry and business. The word “overkill” comes to mind when we see most full tower gaming builds.
Once you can get past these hiccups, however, working with an ATX case and motherboard becomes simple.
Since these cases are so much larger than the previous two, you can fit more fans into them, giving you superior airflow and ensuring that the temperature remains cool.
This will help keep your components from wearing out as quickly, as heat can damage parts in the long run.
Since ATX cases usually feature holes for the cables to travel through, they’re often a lot tidier on the inside when compared to small systems.
Keep in mind how to cable manage your pc as it is an art, and you won’t instantly get good at it just because you have a mid tower, but this type of case can help.
When you’re getting your part list together for your new computer, you won’t have to be as careful about clearance and their sizes when working with a mid tower.
All but the largest components will be able to fit into a computer of this size.
Overall, this kind of case can serve you well. However, it is quickly being surpassed by the mini tower, which typically uses space more efficiently.
While the MicroATX form factor may be smaller, it won’t drastically improve your computer’s portability.
Where the MicroATX shines is in saving space on your desk, and you can even stow it away underneath it.
Since these cases are so much smaller than other towers, you can place them nearly anywhere. And compared to the SFF category, these cases usually accept large components.
As time goes by, many PC builders are expecting the MicroATX form factor to gain popularity. Especially as components keep getting smaller and more powerful.
We would argue that this form factor provides you with the best combination of convenience and small size, as you won’t have to sacrifice much for it.
The only problem with these cases is that they aren’t as popular as mid towers. therefore , you won’t have a selection of as many products to choose from.
While this isn’t a problem if you’re looking for a standard case, it can be hard to find more specialized microATX case designs.
If you’re building your first computer, a Micro ATX case is a great place to start. You’ll have enough space to work in without having to worry about being overwhelmed.
Beyond sheer portability, there are a few other reasons why you would want to opt for a mini-ITX case.
Home theater PCs have been growing more popular recently, and these cases are perfect for them since they’ll be able to fit under your TV without taking up too much space.
Since HTPCs are usually less powerful than performance-oriented models, you won’t need additional space for a GPU or another expansion card.
However, mini-ITX cases have a few downsides that make them a less attractive option than some of the alternatives.
The main issue with these smaller cases is that they feature reduced airflow compared to large ones. This means that your system will run hotter.
A lot of smaller cases also can’t fit an AIO, so liquid cooling will be out of the question unless you’re willing to do some custom work on the case.
Another common problem with these cases is that they will often feature restrictive CPU cooler height and GPU length specifications. So you’ll have to be careful when selecting parts.
What Size PC Case to Choose?
As you can see, the differences between the various computer case sizes can make for a very different machine, in the end.
Therefore, the size of case you need will depend on what kind of PC you want to build and how you intend on using.
We hope that our guide has helped you find the right kind of case for your needs, and we know the pain of struggling to find the right case for a build.