PC Case Sizes: E-ATX, ATX, mATX, and ITX Compared

A PC case not only plays a role in the look of your build but also dictates what kind of parts you can install – now and down the line. In this article, I go over different PC case sizes, such as E-ATX, ATX, mATX, and ITX, and also cover their differences.

Case Size Comparison

In general, there are four main PC case sizes: Full Tower (E-ATX), Mid Tower (ATX), Mini Tower (mATX), and Small Form Factor (ITX). The following is a breakdown of what you need to know about each PC case size.

Full Tower (EATX)Mid Tower (ATX)Mini Tower (mATX)SFF (ITX)
Height>20 in
(50 cm)
<20 in
(50 cm)
<18 in
(45 cm)
~7-12 in
(19-30 cm)
Motherboard CompatibilityMini-ITX
5.25" Drive Bays3-62-51-20-1
3.5" Drive Bays6-136-84-60-2
2.5" Drive Bays0-110-100-42
Expansion Slots7-107-842
Graphics Cards3-42-31-20-1
Case Fans6-123-82-41-3

As you can probably tell from the table, there are no standard measurements for case dimensions. Case manufacturers can (and do) design cases with varying sizes, amounts of drive bays, and fan positions, among other things. This means that you can find comparatively large ITX cases and quite a few mid-tower cases that accommodate E-ATX motherboards.

Computer cases relative size comparison

The PC case models in this relative size comparison are (from left to right), the Lian Li O11 Dynamic XL, Phanteks Eclipse P400A, Asus Prime AP201, and Fractal Design Terra.

Although the Phanteks Eclipse P400A is significantly more compact than the Lian Li Dynamic XL case, it’s an example of a mid-tower case with room for an E-ATX motherboard.

Full Tower (E-ATX)

ASUS ROG Hyperion GR701

Asus ROG Hyperion GR701

Full Tower or E-ATX PC cases are the largest and can handle the most hardware inside them. They also take up a lot of space. These are not too common since they have specific use cases and have a niche market.

With the amount of room that you have to play with, you can install an EATX motherboard, which is wider than the standard ATX motherboard. You can also have additional fans compared to ATX and more case fans. The more space allows for easier custom water cooling, and the case is able to accommodate larger parts.

Full Tower PCs are ideal for enthusiasts who need room for multiple add-in cards (AICs) and storage options. Pictured on the right is an example in the form of Asus’ ROG Hyperion GR701, which is constructed with CNC-machined accents, supports a pair of 420mm radiators, and comes pre-installed with four 140mm PWM fans.

Mid Tower (ATX, E-ATX)

Corsair 4000D Airflow

Corsair 4000D Airflow

The Mid Tower form factor is the most common PC case size since it offers a lot of flexibility and allows you to fit a lot of hardware inside without being as large as an EATX case. Mid Tower cases can accommodate a wide range of motherboards including ATX, mATX, and even ITX. Some are also roomy enough to house E-ATX motherboards.

Since this is a larger case, it can fit smaller motherboards, but it does not work the other way around, which is something that you need to be careful of. This is the case that is going to be just for the general consumer.

The larger footprint allows for large, high-end graphics cards with room to spare for additional AICs. Installing cooling is also much easier since there is room for AIO or custom water cooling solutions. Most ATX cases can accommodate up to 9 case fans, so you get a lot of cooling and airflow.

Moreover, you can install full-size power supply units, and ATX cases have room for 2.5-inch SSDs and 3.5″ hard drives. So, you get plenty of storage and expansion options if you decide to upgrade your setup down the line.

The major drawback – if rather obvious – is that these cases are bigger and taller than mATX and ITX cases on average, so they tend to take up more space.

A very popular example is the pictured Corsair 4000D Airflow. It features tempered glass on the side so you can have RGB lighting, and there is a mesh panel at the front, which allows for increased airflow. Two 120mm fans are included in the box, and you can add six more if needed.

Mini Tower (mATX)

Thermaltake Divider 170 TG

Thermaltake Divider 170 TG

Mini Tower or mATX PC cases come between ATX and ITX in terms of size. So they are bigger than ITX cases but smaller than ATX cases. These have become popular due to inflation and the rising costs of ATX motherboards.

Since you can use a mATX motherboard, you do get more flexibility than an ITX motherboard, such as getting 4 RAM slots and a pair of PCIe slots rather than being limited to one. mATX cases also allow you to use full-size power supply units, larger graphics cards, and bigger CPU coolers. AIO liquid coolers are also supported. More space also means better airflow, fan support, and storage mounting points.

mATX cases come in different styles. We are fans of the Thermaltake Divider 170 TG (pictured), which comes with a tempered glass side panel and a ventilated front mesh panel. Two 120mm fans are included with the case, but you can add more if needed. You also get a dust filter for the top.

Small Form Factor (ITX)



Small Form Factor or mini ITX PC cases are ideal for people who want a smaller PC build that does not take up a lot of space. This form factor has become increasingly popular in recent years. Since Small Form Factor cases are smaller, they are a bit limiting, and you will need smaller or shorter PC parts in order to fit inside. You may need smaller SFX power supplies, smaller motherboards, and shorter graphics cards.

The smaller motherboard also means limited expansion. You can only have two sticks of RAM, a single compact graphics card, and a fairly limited number of case fans. You might need to get low-profile RAM or CPU coolers to fit all that hardware inside the case. Cable management can also be tricky.

The major upside is the footprint of the case. You can fit quite powerful hardware inside most mini ITX cases but they should typically be avoided for very high-end builds due to temperature issues.

One popular option is the pictured NZXT H1 V2. This one comes with an integrated 140mm AIO cooler for the CPU and a 750W 80+ Gold power supply unit.

Features To Watch For

The following are some of the features that you should look out for when in the market for a PC case.

hard drive cage

Hard drive cage

Drive bays and SSD mounting points

M.2 storage is very fast and goes right on the motherboard, so the case you choose will have no impact whatsoever. But if you are using older storage solutions such as 2.5″ SSDs or 3.5″ hard drives, then you need to make sure that your PC case supports it and that there are mounting points for SSDs or drive bays for your HDDs.

Front-panel connectivity

Front-panel connectivity and ports can also be something worth considering. If you want to fast charge your phone or need to quickly connect USB-C devices, then you need to make sure that the front panel has the right ports.

Fans and airflow

Airflow and cooling are very important to ensure that your CPU or GPU does not thermal throttle. When buying a PC, consider the number of fans that come with it and whether or not you will need to buy additional fans.

You should also take into account the design of the case and whether or not it has ample airflow. Cases with mesh panels at the front offer better airflow compared to ones with glass panels.

Water-cooling support

If you are an enthusiast and looking to water-cool your CPU, GPU, or both, then you will need to make sure that your PC case supports water-cooling. Make sure that there is enough room for a radiator and a pump if you are going for a custom water cooling loop.

Tempered-glass panels

Tempered glass is very popular now since it allows you to show off your RGB lighting. If this is important to you, then you should buy a case that has a tempered glass side panel. If RGB is not important or you are not planning on getting parts that have RGB lighting, then this might not be important.

Noise Dampening

If you are looking to build a PC that makes as little noise as possible, you may want to look into cases with integrated noise-dampening materials. This is the opposite approach of mesh-style cases focused on airflow, which can also be relatively silent when idle but will make a fair bit of noise under load. Silence-focused cases can take the edge of this type of noise, with the compromise being airflow.

Frequently Asked Questions

Not directly, but indirectly, larger cases with more fans tend to have better airflow and cooling. This means that the components inside remain cooler and perform better. But this also depends on many other factors.

Normally yes. Larger cases with more fans tend to have better airflow and cooling. This means that the components inside remain cooler and perform better.

ITX PC cases or Small Form Factor PC cases are indeed smaller and more portable as compared to ATX PC cases. But they are not as portable as a laptop.

No. While some PC cases do come with power supply units, that is not typically the case, and buyers are expected to purchase them separately.

How big a case is depends on your preference and use case. If you do not need a lot of performance but value your PC taking less space, then you can opt for an ITX case. Furthermore, if you need to cram as much hardware as possible into a case and need future upgradability, then a larger mid-tower ATX case will be the best solution for most people.

Smaller PCs have limited airflow and less room for case fans, so they may overheat. But to a great extent, that depends on the case and the hardware that you have inside. We do not recommend installing super high-end PC parts into small ITX PC cases.

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