Desktop Computer Case Sizes

Size matters in desktop computer cases. Here, we discuss the different sizes and what causes these differences.

By now, you know that the case houses a computer’s components. It is also tasked with cooling these components. That’s why there's need for enough space for air to circulate. The case determines the size of parts to have for your computer. If you want extensive cooling, a large case will do better than a small size case.

But if you want a compact model that can fit in your home theatre cabinet. A computer with a small-sized case is ideal for you.

There are three major case sizes. The size difference is because of motherboard form factors which we’ll discuss later in this post.

Full Tower PC Cases

These are massive cases that are as tall as 20 inches or higher. You’ll like this case size if you want extensive expansion capabilities.

Full tower cases support massive extended ATX motherboards. They improve thermal performance seeing that they can accommodate extensive water cooling.

Not only that, but these full tower cases also carry 3-4 graphics cards setups and lots of storage space. They also sport 5.25-inch drive bays and slots for more than three fans.

Apart from Extended ATX motherboards (EATX), full tower cases are also compatible with SSI CEB motherboards. The latter is a dual-processor motherboard. It opens the possibilities for overclocking with the help of advanced cooling in a full tower.

Overclocking increases the temperature of the components. Full towers come in handy to support triple heat sinks and big radiators. These features are not possible with a mid-tower case.

Full-tower cases are recommended for gamers, video & photo editors, and hardcore streamers.

Mid-Tower PC Case

This case standard is by far the most popular. It is more flexible in terms of the components it can support without being massive and unwieldy. Mid-tower cases support ATX motherboards. They are reliable in high-end gaming as well as demanding projects like video and photo editing.

Although mid-tower cases fit ATX motherboards, they also vary in size. Most of them range in the 18-inch size. However, the number and placement of fans vary. They support up to three graphics cards and are often expandable for future upgrades.

Mini-ITX Cases

These cases are the complete opposite of the full-tower. One, they can only fit mini-ITX cases. They often have compatibility issues with standard size hardware. As such, you have to check the configuration of every part before buying a mini case.

Mini cases do not support liquid cooling. They have limited space for fans and some do not support full-length graphics cards. They are limited in expandability. Thus, ideal if there’s no need to upgrade the components for a couple of years.

Motherboard Form Factors

The differences in case sizes are because of the different motherboard form factors. That is, the case size has to match the size of the motherboard.

The form factor refers to the specifications of its shape and size. It determines what size circuit board a motherboard will feature. It also dictates the physical layout of the board. And, the location of the mounting holes.

Whether you are building a new computer or looking to buy a new case, you will want to know the motherboard form factor that matches your case choice.

  • ATX Form Factor- Full ATX

The ATX form factor is a revolutionary design developed by Intel in 1995. It is a step-up from the previous Baby AT which had issues with expansion when the CPU was in place. As such, the ATX form factor was developed to reduce the CPU’s interference when one needs to expand.

The ATX form factor is still the most popular design today. Among its notable features are the integrated I/O Port Connectors, built-in PS/2 port, and a single 20-pin connector. It boasts better power supply. Also, the processor and memory sockets are on the back right-side of the board.

These differences have made access and upgrading super easy. It measures 12 x 9.6 inches.

  • Micro ATX

This form factor is seen as an improvement of the Full ATX. It has a maximum size of 9.6 x 9.6. Although smaller than the full ATX, it has a similar configuration to the Full ATX. A case that supports a full ATX can also accommodate the micro ATX motherboard.

Some of the benefits of the Micro ATX is that is can support a small size power supply and high-performance graphics cards.

  • Mini ITX

This motherboard form factor measures only 6.7 x 6.7 inches. It is much smaller than the Micro and Full ATX form factors. It is designed for lower power consumption. Because it is small, it has only one expansion slot. However, the configuration is still the same as that of the full and micro ATX form factors. Only that it is better off in a small case than a full-tower case.

  • Flex ATX

This form factor expands on the micro ATX configuration. It has a max size of 9 x 7.5 inches such that it can be installed in a micro ATX chassis. The Flex ATX form factor has similar I/O panel specifications as ATX motherboards.

  • Nano ITX

Another motherboard form factor is the Nano-ITX. It is smaller than the mini-ITX measuring 4.7 x 4.7 inches. It is designed to consume lower power than Mini-ITX form factor boards. Because of its size, it is not used in desktop computers. But rather entertainment devices like set-top boxes and smart TVs.

  • Pico ITX

This form factor is 75% smaller than Mini ITX. It measures 3.9 x 2.8 inches. This motherboard design is used in small and smart IoT devices. It is also a low-power consumption motherboard that is used in embedded systems. These boards are found in-vehicle computers and industrial automation systems.

  • Mobile ITX

Introduced by VIA Technologies in March 2004, Mobile ITX motherboards are the smallest. They measure 2.4 x 2.4 inches. This design was developed for ultra-mobile PCs and smartphones.

What about DTX Form Factor Motherboards?

The DTX form factor was published by AMD in 2007. It is intended for small factor PCs (SFFs). DTX motherboards measure 9.6 x 8 inches. They augment rather than replace ATX motherboards. They can be used in ATX cases because they have similar mounting hole locations.

The I/O panel specifications are identical to what you’d find in an ATX motherboard. They do not have a redesigned power supply. They require a 24-pin power connector. And similar cooling requirements as the ATX motherboards.


The basic dimensions of a PC case may not be enough when you are out to purchase a new case. You will want to know what motherboard size matches that of your case choice. It’s also important to go deeper. Look at the ease of access, cooling, and cable management when looking at the quality of a computer case.

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