PC Case Sizes - The Complete Guide
All the info you need to find your perfect case
The verdict is in, size does matter!
…for PC cases at least. As with all things technology, there are many confusing terms to know.
We’ve got:
E-ATX vs ATX vs mATX vs mITX.
And…
Small form-factor vs mini-tower vs mid-tower vs full tower vs super tower.
I know, I know, they don’t roll off the tongue.
But in this guide, we’ve put together what’s essential.
You’ll have what you need to understand the differences between computer case sizes and decide the right type for your next build.
Table of Contents
Computer Case Size Comparison Chart
| Mobo Size | Mini ATX | Micro ATX Mini ATX | ATX Micro ATX Mini ATX | E-ATX ATX Micro ATX Mini ATX |
| Graphics Cards | 1 | 1-2 | 2-3 | 3-4 |
| Case Fans* | 1-3 | 2-5 | 3-9 | 6-12 |
| Expansion Slots | 2 | 4 | 5-8 | 7-12 |
| 2.5" Drive Bays | 0-2 | 0-4 | 0-8 | 0-12 |
| 3.5" Drive Bays | 0-3 | 2-6 | 5-8 | 5-14 |
| 5.25" Drive Bays | 0-1 | 0-3 | 1-4 | 2-6 |
*With larger sizes, you will usually be getting more room for bigger fans, not just higher quantities.
PC Case Sizes Explained
Full Tower Size: E-ATX (Extended ATX)
The largest form factor of the popular options, a full tower case gives you the most space for high-end, demanding PC builds that require the best overclocking and plenty of cooling/hardware options.
As you can expect with the large internal dimensions, you’ll also have the best ventilation/airflow capabilities.
If you’re looking to achieve the most powerful build possible (whether for gaming, a server build, or editing/production) then this is the most capable option.
Bear in mind these cases are very bulky, heavy, and on the expensive side.
If you’re looking for something compact or on a budget, check the sizes below.
Note: It’s very rare, but we’ve seen a couple of cases that claim to be “full towers” while still only supporting up to ATX motherboard mounting holes.
We doubt you’ll run into this problem, but before buying a full tower case for EATX, just make sure that the product listing states it will support extended-ATX motherboards.
Mid Tower Size: ATX / mATX
The most popular form factor, a mid-tower case strikes a great balance between space/price and is the “jack of all trades” choice.
For a majority of enthusiast builds, a mid-tower case will still have all that you need for a gaming PC (and most other types).
Providing great cooling options for overclocking and enough space for a strong SLI/crossfire build (if desired) with lots more room for the rest of your hardware (ATX motherboards are also the most popular, giving you lots of options and competitive pricing).
ATX is a great middle-ground. Going larger is only needed if you want to build the most monstrous machine possible. Smaller is better for those after something more compact (and often a little cheaper).
Mini Tower Size: mATX / mITX
Mini-tower cases have become very popular in recent years due to the increasing quality of micro ATX motherboards/compatible parts.
The great thing about this form factor is that it offers decent compactness while still providing enough internal space to fit most hardware.
As we get smaller, bear in mind you’ll, of course, have to be more considerate in what parts you’re choosing and the airflow available for them.
But if your gaming build is only 1 (at a push 2) GPUs and you don’t need lots of other drive bays/expansion slots, an mATX case may be the best option for you.
Another bonus add is that mATX cases are usually a little cheaper than ATX due to the reduced material.
Note that some mini-towers only support mITX, so be sure to check that your motherboard and cases are compatible in size before you buy!
Smaller Form Factor Size: mITX
The smallest form factor on the list.
These are ideal for a portable / LAN party case or someone looking for something quite presentable and flashy (e.g. a streaming build).
You can still install many major parts inside an SFF case.
But be aware that for certain hardware (particularly PSUs/GPUs) you will have to get one of the larger mITX cases.
If however, you’re looking for the smallest computer case possible, you’ll have to buy some less common (“specialist”) parts that’ll be a little more expensive.
If your heart is set on a tiny case, don’t let the above cautions put you off. The form factor is becoming popular enough that even niche parts only carry a slight premium over regular ones!
As long as you check your dimensions, you can still create an awesome gaming setup with an ITX case.
How to choose a PC case size
We’ve recommended the best cases for all build types in our detailed feature here (and some picks further below).
But if you want to understand what the criteria are for your desktop case, here’s what to pay attention to:
Hardware support
As per our comparison chart at the start of the feature, larger cases and the big motherboards they support will give you more options for your hardware.
This includes:
- Expansion slots – More will allow for multi-GPU builds and other components depending on your needs (dedicated sound cards and network cards).
- Note that it’s becoming very common for motherboards to support decent sound, network and Bluetooth capabilities, so many builds will be fine with a case that only has the expansion space for a GPU.
- Clearance for main parts – What dimensions are supported for your GPU, PSU, and CPU cooler? These are the 3 parts that usually have to be considered for case sizes.
- Drive bays
- 5.25″ drive bays – Less popular nowadays, but still useful for things like CD/Blu-Ray Drives and additional card readers.
- 3.5″ drive bays – Suitable for your standard 3.5″HDDs. Having a high allowance here is good for those focused on storage (e.g. video editing builds).
- 2.5″ drive bays – For your SSDs: having a good amount of these will be good for those focused on speed.
- Miscellaneous – Some very large cases will support awesome things like multi CPU/PSU builds and 8 DDR4 RAM slots if you’re interested in power more than a low budget.
Cooling
With big cases, comes big cooling capability.
For air-colling, the larger the tower, the more fans you’ll usually be able to fit in (not just quantity, but size too – often up to 200m).
Larger cases will also include more room for airflow and ventilation which is key for power-hungry builds.
And then there’s water cooling. Whether your focus is on a silent PC build or overclocking, you’re going to have a lot more radiator space in a full/mid-tower. Not to mention how much more pleasant it is to route cooling pipes through a larger case (we’ve had many experiences with tight builds, it can be a pain!).
Nowadays, smaller form factors do have these capabilities, but they’re usually limited in what you can install and more reliant on air cooling.
If you’re serious about buying a water cooling case or pushing your overclocking to the max, go for a larger tower.
Cable management
With larger cases (particularly full/mid) you will commonly see significantly better options for routing your cables into “hidden” areas.
Typically routing behind a compartment underneath the motherboard installation area.
This is not just handy for aesthetics, but also for making the build process a lot easier.
Sure, mATX/mITX will (usually) have the space you need for smaller parts.
But you’ll have to be extra neat/efficient with your cable positioning/tying and ensure you’re not using cables that are overlong (very common!).
If a clean-looking build is extra important to you, you could even purchase a dual-chamber case.
These have dedicated areas to hide not only your cables but your other “less attractive” components (HDDs, PSU, etc).
Size / Design
Now as nice as it is to have great room for parts, cable management, and airflow, the small form factors have a very important thing going for them:
Portability.
You may not really care about this if you plan to have your PC stationary.
But if you’re a LAN party regular and have limited space or plan to use your build in multiple locations (e.g. a VR demo PC) then don’t underestimate the usefulness of this perk.
And then there’s aesthetic.
It should go without saying that cases of all shapes and sizes come in really nice designs.
But it all comes down to personal preference; do you want a monolith towering over your desk or a small compact machine that fits tightly with the rest of your setup?
Price
As far as the case itself goes, smaller form factors will offer the best value due to fewer material requirements.
You can, of course, get PC cases for all form factors in all price ranges, but if we’re talking about value, $ for $, you’re going to get more bang for your buck from small options.
There is a balance here, however.
If you go too small (mainly mITX/SFF cases), you may run into needing “specialist” PSUs/GPUs if the dimensions are low.
These parts tend to be more expensive than their mainstream alternatives.
Because of this, MicroATX tends to be the sweet spot, which leads us nicely into our budget choice…
Which PC case size should you get?
Budget gaming PC case
For a cheap PC build, the best option is usually Micro ATX.
This form factor and motherboard type will have less space and feature availability than ATX/E-ATX.
But you’re not going to care about losing these things in a budget PC (e.g. high PCIe slots and cooling options that would be excessive for a cheap build).
mATX hits the sweet spot between being smaller, but not too small that they lack compatibility with major parts and require “specialist” hardware like many mITX towers.
One of our favorite “all-around” recommendations for a cheap gaming PC case is the Cooler Master Q300L.
It’s popular for a reason; offering impressive utility, build quality, and design for its price range.
Looking for something else? All our PC case articles provide the best budget choices for their category, whether it’s a silent build, the best overall cases, or the cheapest cases we recommend.
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