What is Motherboard Form Factor?

There’s no denying that the motherboard is one of the most important parts of a computer. So much so that whatever the computer needs to use is either located on the motherboard, can be plugged to the motherboard through slots or external ports, and in recent days, can be received wirelessly over a network or from the cloud.

All these features need to be contained and controlled somehow to ensure proper performance as per the spec sheet and your requirements. So what is motherboard form factor?  Basically, the motherboard form factor is used to refer to the shape of the motherboard, its dimensions as well as the layout of components on its surface.

See a motherboard is a modular component meaning that it can expanded. However, not all motherboards are created equally. Depending on your budget, size, and feature requirements, motherboard may offer lower or a higher degree of expandability.

For this reason, we see the motherboard comes in many different shapes and sizes, also known as the motherboard form factor. Different motherboard manufacturers serve up different specs to their customers. The form factor is what helps determine the physical specifications of the board which in a way influences its overall capabilities.

Also Read: Why Motherboard is Called Motherboard?

Understanding What is Motherboard Form Factor?

What is motherboard form factor
The different types of ATX forms factor most commonly found. The ITX series of MOBOs are also quite common.

As mentioned earlier, not all motherboards are created equally. Some are compact, others are large server grade motherboards. However, there has to be a certain degree of order to the chaos.

That is where form factor standardization comes in to play.

With many board manufacturers out there, it is important to regulate what OEMs are doing.

The form factor had its humble beginnings in IBM in the mid-80s. IBM introduced one of the first successful motherboards for personal computers, and it was called Planar (this was back in 1981).

Then in 1984, the first motherboard form factor was introduced. The form factor was referred to as the AT (Advanced Technology) but still went by the name “Full AT”. It measured 12 x 13.8 inches.

A year later, IBM also released a new form factor known as the Baby ATX.

The history of the development of motherboards and their defining form factors is one marked with substantial improvements which gradually resulted in the reduction of the size of personal computers.

While IBM played a huge role in seeing the development of game-changing form factors, other companies like Western Digital VIA Technologies, and Intel also had a huge contribution to this trend.

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Purpose of the Form Factor

Many board companies invest millions of dollars into research and development for their boards. As such, it would be very likely that companies would be adopting different form factors for their boards.

The form factor as a standard is meant to bring uniformity to all these companies.

This is to ensure that motherboards can be used with particular cases or be fitted with certain equipment.

A form factor is also a gauge for the amount of expandiliby a motherboard can offer. In others, each motherboard form factor has a certain standard and a maximum of how many CPU, DIMM, PCIe, SATA etc slots it can offer.

Also Read: Best Motherboards with Integrated Graphics

Popular Form Factors

The following motherboard are quite popular among Servers, PCs or embedded system devices.


Also known as Standard ATX. It was released by Intel in 1995. It measured at 12 x 9.6 inches, therefore, had its applications rooted in desktop and workstations.

This is one of the most common form factor found on PCs and most gaming rigs.


Extended ATX is a form factor generally used for top end PCs or for server grade computers.

As far as gaming computers are concerned, these are used by the top elite enthusiasts. The board measures at 12 x 13 inches.

Micro ATX

This is a smaller form factor compared to the ATX. It was developed in 1997 by Intel and it measured 9.6 x 9.6 inches.

This is the most common form factor for normal day to day home use PCs.

Mini ITX

This standard was created by VIA Technologies in 2002. It allowed for smaller desktop computers since it measures a mere 6.7 x 6.7 inches.

Compact PCs generally use this form factor.

Nano ITX

Also developed by VIA Technologies, this form factor was much smaller than the one before it, measuring 4.7 x 4.7 Inches.

Pico ITX

This was developed purposefully for embedded systems instead of personal computers. Its dimensions were just 3.9 x 2.8 Inches.

Importance of Motherboard Form Factor

There are plenty of reason why motherboard form factor standardization is crucial.

1. The Standard Exists To Control Motherboard Size

computer cases
Source: Hackintosh

A motherboard has a lot of components with varying shapes and sizes. This can easily result large boards.

Manufacturers may develop larger boards with multiple expansion slots for their users. But, issues start to arise when looking for the case.

The form factor goes a long way in determining the kinds of cases you can use for a specific board. With expertly placed mounting holes, a motherboard is capable of fitting in just a specific case.

Therefore, having a free market devoid of the form factor standard would prove hectic as case manufacturers would have to produce multiple case sizes and this would be expensive, a cost that would eventually be transferred to the consumer.

The standard lets us create cases that fit boards from different manufacturers easily.

Also Read: Best Motherboards with Thunderbolt

2. Determines the Degree of Expansion

As with all PC, the main advantage with the size is the degree to which you can expand your device.

Many modern motherboards allow expansion through the provision of slots such as the PCI-Express and Serial ATA.

Larger boards will have several ports and slots for expansion of various components like memory and storage while smaller boards may have only a few extra slots.

For people looking to max out the performance of their computers, larger form factors are usually ideal.

Nevertheless, on the opposite end of the spectrum are people who would instead prefer a more subtle and smaller package with the minimal requirements for good performance.

In recent years, small form factor computers have become popular for PCs.

3. Determine The Power Supply

Just like motherboards, power supplies also have their form factors that determine not only their sizes but also their pin counts.

While some power supplies can be used interchangeably without any issues before you get one you should first consider your case configuration, which goes hand in hand with your motherboard form factor.

Here are some popular power supply form factors today and the motherboard form factor they correspond to.

  1. LPX style power supply – It is commonly used with Baby-AT, Mini-AT, and LPX motherboards.
  2. ATX Style power supply – Commonly used with ATX, Micro-ATX and NLX motherboards
  3. SFX style power supply – Commonly used with Flex-ATX and Micro-ATX boards.


So what is motherboard form factor? In the most simplest of terms, the form factor of a motherboard determines its size and shape.

This is an essential thing to know when purchasing a new board or a new PC. Not only will it determine the size of the case you will need, but it will also determine the kind of CPU, components and peripherals you can use because different boards have different socket types for different chipsets.

The standard itself was invented by IBM and over the years it has proven to be very useful as more and more manufacturers are developing motherboards that need to work with equipment from other vendors.


We are team of two engineers with a keen interest and a passion for PC builds and hardware.

PCGearLab.com is essentially the culmination of our enthusiasm towards this subject. We review PC peripherals and hardware, talk about custom builds and informative topics regarding troubleshooting issues, understanding a component better and general tips for DIY PC builders.