Selecting the wrong PC case size can lead to issues such as component incompatibility and a complicated build process. On the other hand, getting it right the first time will help smooth out the PC building experience and help make it a pleasure, not a chore. Let’s dive in.
PC Case Sizes at a Glance
There are four main categories of PC cases. These differ in size and motherboard compatibility, with larger cases fitting larger motherboards. Here’s a quick computer case size chart to give you an idea:
|Mini-ITX / SFF
|Around 2-19 inches
|Around 12-18 inches
|Around 18 inches
|Mini-ITX, Micro-ATX, ATX, occasionally E-ATX
|Around 22-25 inches
|Mini-ITX, Micro-ATX, ATX, E-ATX, XL-ATX
Of course, there are always exceptions to these rules, such as Micro-ATX (or Mini-Tower)-sized cases that only fit Mini-ITX boards. So you should always check compatibility before purchasing. Thankfully, all case manufacturers will list motherboard support for their cases, so it’s just a matter of checking on the website before buying.
Unsure what the differences are between the three motherboard sizes? Check out our Mini-ITX vs. Micro-ATX vs. ATX comparison for more info.
Mini-ITX and Small Form Factor (SFF) Cases
Mini-ITX and small form factor (SFF) cases focus on minimalism, portability, and compactness. They generally only accommodate Mini-ITX motherboards and SSDs, with restrictions on CPU cooler height and GPU size.
While almost all SFF cases are Mini-ITX cases, not every Mini-ITX case is a small form factor case. SFF cases usually have a volume of fewer than 20 liters, with the smallest Mini-ITX cases even sneaking in under the 10-liter threshold.
For example, NZXT’s H210i only fits Mini-ITX motherboards but is too large to be an SFF case at 27 liters. Compare that to Louqe’s Ghost S1, which also takes a Mini-ITX motherboard but is only 8.5 liters in its stock configuration.
The main advantage of Mini-ITX and SFF cases is their compact dimensions. They’re small enough to place anywhere without needing to make a ton of room. Their size makes them exceptionally good for secondary systems or where it’s better to have something minimal or easily tucked away.
SFF cases are perfect if space is at a premium, such as for a home theater PC or a living room-friendly PC. They’re also excellent if you need a portable rig. If you shuttle back and forth between college and home, an SFF rig may offer better performance and value than a high-end laptop. You can even find Mini-ITX cases with handles designed expressly for this purpose.
The most apparent drawback of compact cases is the limited space on offer. The small size of an SFF case leads to a variety of challenges. For example, you have much less room to work, often making the build process more challenging. Cable management, in particular, requires a lot of planning and foresight in an SFF case.
SFF cases also require SFF-specific components, such as smaller SFX power supplies and compact graphics cards. These can cost significantly more than their full-size counterparts, adding to the already-hefty cost of SFF cases and Mini-ITX motherboards.
You also have to live with limited expansion options with SFF cases. Because they’re so small, they often lack space for additional components or upgrades. This can be a problem for users who want to upgrade in the future. Finally, the limited space impedes airflow, which can lead to overheating issues.
A step up from SFF in terms of size, mini-towers (also known as Micro-ATX towers) offer more space for powerful components but not much more expandability. This PC case size has a place for budget-conscious builders who want more than an SFF case offers without the cost and size of a mid- or full-tower.
As the name suggests, Micro-ATX cases fit Micro-ATX (or mATX) motherboards. Thus, these cases provide more room to work with than SFF cases while still being small enough to fit on most desks. If you’re looking for a PC case size that’s still small and stylish but has the potential to grow with your needs in the future, mATX cases are a great choice.
Micro-ATX cases offer space savings compared to larger towers without requiring the bespoke components that SFF cases ask for. come into play. If you need a relatively compact rig without the headache of SFF builds, then a mini-tower could be a reasonable option.
These cases are also the smallest PC case size where standard-sized components come into play. If you choose your parts wisely, you can squeeze a lot of computing power into a deceptively small package with a Micro-ATX case.
While mini-tower cases are often significantly larger than their Mini-ITX and SFF counterparts, they still aren’t great if you want a ton of options. Even though they use standard, full-sized components, you may find mATX cases lacking in drive bays, radiator mounts, or expansion slots.
That said, the limited expansion of mATX motherboards means that some of these drawbacks aren’t surprising. The primary issue with mATX cases, however, is poor value. While they are smaller than mid-towers, they’re not that much smaller. They’re also often not that much cheaper than a budget mid-tower, which will often have better expansion and cooling.
For example, the Cooler Master NR400 is a great mini-tower case, but its $95 MSRP puts it in direct competition with the larger (and much better, in our opinion) Phanteks P400A mid-tower. So, unless you really need the minor space savings you’ll get from an mATX tower, you should probably consider a mid-tower case first.
The most popular form factor, and for a good reason, mid-tower cases strike a near-perfect balance between size, expandability, and features. Mid-towers fit the two previously mentioned motherboard sizes, Mini-ATX and Micro-ATX, with the addition of ATX and sometimes even E-ATX boards.
This case size is ideal if you want the best blend of advantages from the other computer case sizes with the fewest disadvantages.
Mid-tower cases usually offer the best value. These represent the sweet spot in the computer case size hierarchy for optimum airflow, component compatibility, and future expansion. Mid-tower cases will handle almost everything you’d want in a high-end gaming rig, including high-end GPUs and large 360 mm AIOs.
Mid-tower cases are the most popular case size, so you get the most choice when shopping in this product category. No matter your needs, you’re likely to find a mid-tower case that fits your requirements at an affordable price.
The healthy competition in this size category encourages manufacturers to keep innovating, whether it’s the novel aesthetics of the Fractal North or the smart design and modularity of the Lian Li Lancool 216.
The main downside, if you can call it that, is that mid-towers are a generalist option. They don’t excel in any particular areas, offering a safe middle ground that should appeal to as many users as possible.
Mid towers don’t have the portability of an SFF case or the outright versatility and extreme hardware potential of a full-tower case. They’re more a jack-of-all-trades, master-of-none; fine for most users, but those with specific needs will want to look elsewhere.
The variety we discussed earlier can have a downside, too. While choice is great, the sheer number of mid-towers on the market means it can be hard to find the right mid-tower. So you’ll likely have to spend a bit more time researching compared to other case sizes.
Full-tower cases are the largest mainstream PC case size available. They aim towards ultimate expandability, with enough room for ultra-high-end setups, servers, and workstations. Full-towers accept all the previously mentioned motherboard sizes, plus E-ATX and sometimes even XL-ATX.
Full-tower cases are ideal if you need a ton of room for your build, whether it’s complex custom water-cooling loop or a dual-CPU workstation board. Some full-towers, like the “super-tower” Corsair Obsidian 1000D, even have room for a secondary Mini-ITX system. If it must be a full tower and nothing else, we’ve got a list of the best ones here.
Full-towers have one significant advantage: size. Full-towers are more versatile than other cases, with room for almost anything you’ll ever want to install in a PC case. Want triple radiators? Need room for ten or more hard drives? A full-tower is the case for you.
If you’re concerned about component sizes, a full-tower is also a great brute-force solution to overcome clearance-related woes.
The size also makes full-tower cases a joy to build in. Not only is there generous space for your hands during building, but you have a blank canvas to try non-conventional builds. For that reason, full-tower cases are also perfect for showcase builds.
Unsurprisingly, these cases take up a ton of space. They won’t work in space-restricted environments or situations where you want a svelte case that blends into the decor. Full-tower cases are also expensive, with some high-end examples coming in well above $250.
While the size and compatibility strengths over smaller cases are undeniable, not every build truly takes advantage of the extra room a full-tower offers. Unless you’re building something extremely high-end, you’ll probably find that a decent mid-tower will be enough for your components.
Trying to choose between a mid- and full-tower case? Head to our mid-tower vs. full-tower case comparison to see which is right for you.
So, what’s the right PC case size for you? It depends on your preferences and how much space you need. If you want a compact rig, then you’ll need a Mini-ITX or SFF case. On the other hand, if you’re already planning a crazy triple-radiator setup, then only a full-tower case will work for you.
However, a mid-tower is probably the safest choice for most users, offering enough room for powerful builds without the space and cost issues of the two extreme sizes. But choosing the right PC case size is only one part of the equation: for the rest, head over to our guide to choosing PC cases for info on all the other crucial considerations.