Which Computer Case Size Is Best For Your Next Custom PC Build?

Lets find the right PC case size for your build.

Computer Case Sizes PC Case Sizes
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When it comes to part picking your next custom build PC, deciding what size PC case to use can be a confusing and tedious factor. As we enter into the 21st century, consumers have never had more options to choose from when it comes to case size and form factor. Gone are the days of deciding which beige desktop case best suits your office space. We now have cases that range from the luxurious, all-singing-all-dancing full towers, down to subtle mini-ITX alternatives. It really is an exciting time to get into PC building.

If you are new to PC building, there’s a chance you don’t yet realize the importance that comes with choosing the right computer case size. The size of your case, ultimately, determines the size of the components you can fit in it. It also dictates how many case fans you can install and whether or not you can water-cool it down the line – all factors that have a knock-on effect if you plan on overclocking your PC in the future. Computer case size also has a big impact on future expansion, hard drive space, drive support, and aesthetics too.

The following article will focus on taking a closer look at some of the more intricate factors that affect the size of the case you should be choosing for your next PC build. We’ll be exploring the main form factors, the different size options, and the pros and cons that come with each. We’ll also touch upon how each case size is affected by cooling, what components should (and shouldn’t) be used with each case size, and pretty much every other factor that might affect your computer’s case size.

So, with all that being said, let’s waste no further time and jump straight into it!

Computer Size Comparison

not fit into this guide – but for the most part, it’s pretty accurate.

Computer Case Size Comparison

 Full TowerMid TowerMini TowerSmaller Form Factor
5.25″ Drive Bays3-62-51-21
3.5″ Drive Bays6-136-74-61-3
2.5″ Drive Bays0-100-60-40-2
Expansion Slot7+5-742
Graphics Cards3-42-31-21
Case Fans8+3-82-41-3

Computer Case Size Breakdown


Full Tower Case/ E-ATX Case Size

Full towers have always attracted the attention of enthusiasts for their expansion compatibility, custom loop support, and improved thermal performance (in most cases – but not all). Having said that, it isn’t just gamers and PC enthusiasts that make use of this size bracket, though; server cases are also considered to be EATX as they need to accommodate an extra CPU and RAM.

Any build that wants to make use of an E-ATX, or SSI CEB sized motherboard, will most likely need to go in a full tower case. The smaller mid towers only have room for up to ATX. Furthermore, a full tower case is a great option for people looking to perform hard overclocking on their components.

Overclocking requires a lot of cooling as heat can ramp up rapidly when components are pushed to their limits. To combat the additional heat that comes hand-in-hand with overclocking, big radiators, triple heat sinks, and water cooling are often implemented to try and keep temps as low as possible. Having said that, they aren’t exactly small.

It isn’t just clearance that’s cause for concern when cooling elaborate builds; you also need to concern yourself with airflow – luckily, full tower cases have this in abundance.

Multi-GPU setups via SLI and crossfire are also a big advance when using larger, full tower cases. They offer a ton of expansion slots, often with vertical GPU mounting for large GPU support – great for hardcore gamers, streamers, and high-workload video editors.

Motherboard form factor

Mid Tower/ ATX, Micro-ATX Case Size

Mid towers are the most popular amongst custom PC builders as they offer some of the greatest flexibility on the market (plus they don’t weigh a ton!). Many enthusiasts prefer slightly smaller, more compact looking cases to showcase their various high-performance components and RGB setups. This is where the mid-tower case comes into its own – offering excellent versatility and aesthetics at the same time.

Like full tower cases, most mid-tower cases can support two graphics cards – with some even offering a third as well. Even though three is probably more than enough PCI-e room for most gamers, it still gives builders an additional couple of PCI-e slots for future expansion down the road. It is important to know that modern high-end GPUs (2080Ti’s for example) can take up two PCI-e slots on your motherboard. Just remember to always check the specs of a motherboard to make sure it’s compatible and spacious enough to accommodate dual-GPUs.

Of course, mid-tower cases offer a much smaller interior space (compared to the full tower), which ultimately leads to a rise in ambient temperature. This is mainly down to the fact that they simply can’t accommodate as many case fans. Effectively leading to less airflow inside the case. However, as we learned from our comprehensive look at PC case fans, that this isn’t always the case.

At the end of the day, it isn’t just airflow that’s going to be impacted in smaller cases; there’ll also be fewer routes or space to cable manage, less support for hard drives, and less room to equip large water-cooling configurations.

Mini Tower/ Mini-ITX, Micro-ATX

Smaller cases have always interested people thanks to their savvy space-saving designs, portability, and their incredible aesthetics when fully built. There are quite a few things going for mini-towers, and obviously, price is a big one.

Aside from the very unique looking tempered glass mini-ITX cases, the cases in this size category are often a bit cheaper. These smaller cases also fit smaller (cheaper) components, meaning your overall build is going to come out cheaper overall – think low-profile GPUs and subtle cooling configurations.

This obviously isn’t the case for all mini-tower cases, though. It’s quite popular amongst custom builders to set up custom loops in these smaller cases as it can have some astounding aesthetic results.

As you can probably imagine, these cases obviously offer much less in regards to hard drive space and expansion slots. Large GPU’s can sometimes be problematic for some cases, so just be sure to check the clearance of the case you’re looking at before purchasing.

Smaller Form Factor/ Mini-ITX

Smaller form factor cases are a tight squeeze, but they do give builders some fantastic options. Depending on the case, you can fit some really powerful components into these miniature cases, and they can be great for LAN parties or as HTPCs.

These little machines can save you a lot of space in whatever environment you choose to set one up. Not only will these take up no room at all, but you can easily move it around the house/ flat and even take it away with you thanks to their small stature.

PC Case Features To Look Out For

So, like pretty much every component on the market, each of the major case sizes comes with their own unique blend of features, benefits, and downfalls. As a general rule of thumb, the more expensive the case, the more features it comes to the table boasting – most of the time anyway. If you are new to PC building and are struggling to decide which case size best suits your needs, then read below to familiarise yourself with some of the major factors.

Drive Mounting – One important factor to consider is hard drive space. You need to make sure your new PC case has enough room for your current 2.5″ SSD/ 3.5″ HDD drives – not to mention any 5.25″ drives you may have. Hard drive mounting options come in many forms, so it’s good to know exactly where they might be located when considering a case.


Some cases will provide the correct mounting space for your drives directly onto the sheet metal of the motherboard tray. This will usually be four holes that you screw your drive into. Some cases will provide you with a removable caddy to easily access your drives – a kind of plug and play approach – and others will just have basic drive cages found in and around the interior.

Ultimately, every case has space for hard drives. Understanding how much space you need, and whether or not the case can accommodate that, is the question you need to be asking yourself.

Reference the table at the top of the page for hard drive support across the main case sizes.

Toolless design – As mentioned above, some manufacturers take away a lot of the stress that comes with PC building by making certain aspects much easier and simpler. One of the modern approaches we see implemented in higher-end PC cases is called toolless design. This can be anything from a thumbscrew to a clip-on drive bay; these parts of the case will make your life easier but can incur extra costs. It doesn’t stop their either, in high-end cases, you have everything from toolless hard drive caddies, motherboard cut-out covers, and removable PSU shrouds too.

Cable management – Budget cases tend to dismiss the act of cable management by removing helpful aids. They generally offer less room for hiding cables at the back, whilst losing out of key features such as grommets, tie sports, and PSU shrouds.  Cable management is hard, and it can take time to get things perfect, but when done right, it makes a PC build look fantastic.


Cable management is particularly important with smaller cases as there is less airflow and higher temperatures in general. There are cable management cut out holes in most cases today with some even featuring rubber grommets. Rubber grommets will improve the overall aesthetics but can, again, cost extra or only feature in more premium cases.

Water-cooling support – The best all-in-one coolers available in today’s market are nothing compared to custom loop water cooling (when referencing component temps) and never will be. When it comes to a custom loop or all in one cooler, you are going to need radiator support. Of course, the bigger the case, the more radiator support you will have – this is usually labeled in the case’s specs.

It shouldn’t have to be said, but if you are planning on installing a huge 360mm+ radiator into a mini-tower, then you could meet some issues regarding clearance. Water cooling doesn’t have to go in a large case to work or look good – take the Comino Otto as a prime example – but you just need to make sure your parts are compatible!

PC Case Sizes - Our Best Recommendations

So, with all that in mind, you probably have a much better idea of what case size is best going to suit your specific needs. Now’s the time to start thinking about which case (within that size group) you’re going to use for your next PC build.

Luckily, we have a ton of experience in this sector. Below, we are going to outline some of the standout picks for each category.

Full Tower PC Case

For me, the best full tower case I’ve used in a while is the Thermaltake View 71 – and not just because it offers a stunning design and excellent RGB support. However, others in the office seem to prefer the Phanteks Enthoo 719. Whichever one you decide to opt for, you’re going to be getting a super case regardless.

Mid Tower PC Case

There are a ton of mid-tower cases to choose from that all offer excellent build quality, great airflow, easy build assembly, and plenty of options for customization. However, for me, I’ve opted for the hugely popular Fractal Design Define S2. It might be slightly pricey, but you get everything you need and more from this Fractal beast.

Mini Tower PC Case

Lastly, we have the Mini Tower PC case. This pic comes from a case we recently reviewed and fell in love with almost immediately. It’s a great looking case that offers good airflow and cable management to boot. We are talking about the NZXT  H210.

Small Form Factor PC Case

Finally, we have the humble yet versatile small form factor PC case. Now, for me, the best example of versatility and customization in a case of this size comes in the shape of the Thermaltake Core V1. It’s small, and a cube – so not much in aesthetics – however, it offers great versatility, decent amounts of clearance, and good airflow too.

Final Word

So guys, there you have it, our comprehensive look at computer case sizes.

We’ve concluded that, for the enthusiasts out there, a full tower case would probably be the way to go. Not only are they the ultimate for airflow, but they have ample room for upgrades, and of course, water cooling too.

For a well-rounded case option, you may be leaning towards the ever-popular mid-tower PC case. A mid-tower case can fit all motherboard sizes apart from EATX and server boards, making it a versatile case option. Not only will these cases have the room to fit large components, but they don’t leave you with large distances to cover when it comes to cable routing – making them easier to cable manage at times.

For a smaller case option, you can always go for the smaller form factor cases, but a mini-tower is probably the better way to go. A mini-tower can be great for anyone who would prefer a bit of portability from their PC. If you are struggling for room in your bedroom, office or workspace, then a mini-tower could be ideal.

Of course, what you pick is entirely down to your preferences and build specifications, but now you are clued up on what the computer case sizes can do for you, there is no stopping you!

Let us know what you thought of this guide by leaving us a comment below. Better still, head on over to our Community Hub where you can discuss everything from computer case sizes to the latest GPU.