How to Check Form Factor of Motherboard? – 4 Ways to Figure Out

Motherboards are NOT of the same size. Some are small while others are large. It is very important to check the form factor of your motherboard to make sure that it will fit in your PC case. As such, this article will serve as a guide on how to check form factor of motherboard.

Fortunately, it is quite simple to check the form factor of your motherboard. You can either head over to the motherboard’s technical spec sheet which should almost always have the form factor specified, or you can physically inspect the size and dimensions of your motherboard with a measuring tape or a ruler.

You also have to understand what the different form factors are called. Since in most cases, instead of the physical dimensions written, most motherboard and PC case specsheet will specify the size through their form factor name such as ATX, Micro ATX etc.

So let me first introduce all the common form factors to you.

What are the Different Motherboard Form Factors

Before you learn how to check form factor of motherboard, it is important to understand what different motherboard form factors look like

Motherboard form factors essentially define its physical size and dimensions. In doing so, the form factor also determines:

  • The size of the PC case required
  • The location of the mounting holes and the standoffs
  • The power supply required
  • The amount of expansion capability it offers – to an extent

There are three common motherboard form factors for commercial PCs and one common form factor for workstation grade PCs

The following table summarizes the different form factors:

Form FactorDimensionsPurposeRemarksNo. PCIe Slots
ATX
(aka Full-ATX
Standard ATX)
12 x 9.6 inches
305 x 244 mm
Commercial- For Gamers and Professional
- Fairly common
- Best expansion capability for commercial purpose
2-3 x16
2-3 x1
Micro ATX
(aka mATX)
9.6 x 9.6 inches
244 x 244 mm
Commercial- Feature affordable motherboards
- Moderate expansion capacity
1-2 x16
1-2 x1
Mini ITX6.7 x 6.7 inches
170 x 170 mm
Commercial- Smallest motherboards or PC
- Minimal expansion capacity
- Expensive due to their compact design
1 x16
Extended ATX
(aka E-ATX)
12 x 13 inches
305 x 330 mm
Workstation- Intended for workstation builds
- Expensive and compatible only with specialized workstation CPUs.
4-7 x16

Here is how the different motherboard form factors look like:

ATX – aka Full ATX – aka Standard ATX

ASUS Prime Z690-P D4 ATX
ASUS Prime Z690-P D4 ATX motherboard. Source: Newegg

Micro ATX – aka mATX

ASUS Prime Z690M-Plus D4 Micro ATX
ASUS Prime Z690M-Plus D4 Micro ATX motherboard. Source: Newegg

Mini ITX

ASUS ROG Strix Z690-I Gaming WiFi Mini ITX motherboard with ddr5 support
ASUS ROG Strix Z690-I Gaming WiFi Mini ITX motherboard. Source: Newegg

Extended ATX – aka EATX

 
ASUS ROG Maximus Z690 Extreme Glacial EATX
ASUS ROG Maximus Z690 Extreme Glacial EATX motherboard. Source: Newegg

These form factors are designed by different companies. ATX form factor was first invented by Intel in 1995 to replace the older AT form factor.

The ITX form factor was designed by the VIA technologies in 2002

It should be noted that there are several more form factors as well such as NANO ITX- Pico ITX etc, but these are not used for PC and for workstations.

motherboard form factor comparison
Comparing different motherboard form factors. Source: Wikimedia.

Also Read: Are All Motherboards the Same Size?

How to Check Form Factor of Motherboard?

With the knowledge of what different motherboard form factors are and what they look like, it should be fairly simple to check your motherboard’s form factor.

There are essentially four ways:

  1. Through the Technical Spechseet of the Motherboard
  2. From the Motherboard’s Name Itself
  3. Through Physically Measuring the Dimensions.
  4. Through Certain Visual Cues

1. Checking Motherboard Form Factor Through the Specsheet

One of the easiest ways to check what form factor your motherboard is is through its technical specsheet.

To do this

1. Type the name of your motherboard make and model in Google search

gigabyte b560 AORUS PRO AX motherboard google search

You can also use the manufacturer’s website to find your motherboard, but I find Google search as a very convenient method.

2. Head over to the main search result for your motherboard (often the first result)

3. With the motherboard’s overview page open, head over to the specification page.

aorus B560 specifications

4. In the specifications page, look for a section regarding the motherboard’s form factor.

How to Check Form Factor of Motherboard

As you can see, the Gigabyte B560 AORUS Pro AX has the ATX form factor.

Of course for this method to work, you need to know what motherboard make and model you have. If you are having a hard time finding what motherboard you have, then I have written a comprehensive guide on that too:

2. Figuring Out the Form Factor From the Motherboard’s Name Itself

One very neat trick to find out what motherboard form factor you have is to look at the motherboard model name itself.

Specifically, you are looking for letter “M” or “I” after the chipset number.

All motherboards have the chipset model in their name as well. For instance:

  • Gigabyte Aorus B560 Pro AX features the Intel chipset B560
  • ASUS Tuf Gaming X570-Plus has the AMD X570 chipset.
  • MSI Pro Z690-A has the Intel Z690 chipset

So an so forth…

Now, if a motherboard has the letter “MIMMEDIATELY after its chipset, then it is almost certainly a Micro ATX motherboard.

If a motherboard has the letter “I” IMMEDIATELY after its model, or after a hyphen “-“ or if it has ITX written in its name, then it is a Mini ITX motherboard.

If a motherboard’s model does not meet the conditions above, then it is most probably an ATX motherboard.

Here are some examples,

  • ASUS Prime B560M-A: this is a Micro ATX motherboard
  • ASUS Prime Z690-P: This is an ATX motherboard
  • MSI MAG X570 Tomahawk WiFi: This is an ATX motherboard
  • Asus Prime A320I-K: This is a Mini-ITX motherboard
  • ASRock Z690M-ITX/ax: This is a Mini-ITX motherboard

Again, you will need to know the exact make and model of your motherboard to figure this out.

Also Read: Do All Motherboards Fit in Any Case?

3. Through Physically Measuring the Dimensions

The last and the final method to check what motherboard form factor you have is through the good old physical inspection.

Grad a measuring tape or a ruler and physically measure the length and the width of your motherboard.

This method is best if the motherboard is being bench tested. If it is already installed, then it can get a bit tricky to get your measuring tape inside the PC chasses.

4. Through Certain Visual Cues

There are some physical hints from the motherboard itself that can give you a good idea about what motherboard you are looking at.

  • If a motherboard only has a single PCIe slot of x16 length located at the bottom of the board, then it is almost certainly a mini-ITX motherboard.
  • If a motherboard has 2 xPCIe x16 slots and if one of them is located near the bottom edge, then it is most likely a micro-ATX motherboard.
  • If a motherboard has 3 x PCIe x16 slots, then it is almost certainly a Full-ATX motherboard.
  • If a motherboard has more than three PCIe x16 slots, then it is almost certainly an E-ATX motherboard.
ASUS TUF Gaming B560M-PLUS
ASUS TUF Gaming B560M-PLUS. A premium mATX motherboard with two PCIe x16 slot. The second is located on the bottom edge. mATX motherboard do not have the space to fit 3 x PCIe x16 slots.

It should be noted that the PCIe slot configuration can vary drastically across motherboard. It is not necessary for all micro-ATX motherboards to feature 2xPCie x16 slots. Many micro-ATX have only a single PCIe x16 slot.

What would separate a mATX from a mini-ITX in this case is that on mATX- the x16 slot is located somewhere near the center of the board. An mATX also has several x1 slot. A mini-ITX, on the other hand, has only one PCIe slot of x16 size and is located on the bottom edge of the motherboard.

Similarly, it is not necessary for all Full-ATX motherboards to feature 3 x PCIe x16 slots. Many feature only two x16 slots. Some Full-ATX motherboards can even feature only one x16 slot.

Also Read: Do Motherboards Come with CPU and RAM?

FAQ

How To Tell if a Motherboard is ATX

ATX motherboards are the largest commercial motherboards. They are also the most common. You can tell if your motherboard is ATX or not by either measuring it dimensions, which should be 12 x 9.6 inches (305 x 244mm), or by its name.

ATX motherboards do not have the letter M or I after the chipset model in their name.

But perhaps the most definitive way to check is by heading over to the specsheet.

How to Tell if I Have a Mini ITX Motherboard?

For starters, mini ITX motherboards are very compact. They are pretty hard to confuse with any other form factor since with a dimension of 6.7 x 6.7 inches (170 x 170 mm) they are tiny compared to the mATX or the Full-ATX motherboards.

Another very important give away for mini ITX motherboards is that they only have a single PCIe x16 slot. They offer no other PCIe expansion slots.

ASRock Z690M-ITX
ASRock Z690M-ITX. Mini ITX motherboard have one x16 slot. They offer no other PCIe slot.

Also Read: Can You Upgrade a Laptop Motherboard?

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Author:

Atif Qazi
Atif Qazi is the founder of PCGuide101. He is a digital nomad who loves everything PC. He is a PC builder, tech enthusiast, engineer, and a lover of single player lore-rich RPG games.

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