What is a Form Factor?

Form factor for computers refers to the size, shape, and physical specifications of hardware or hardware components. Computer form factor is used to describe any physical aspect of a computer system. Form factor is very important for connection compatibility.

Importance of form factors

The most obvious example of a computer form factor is the difference between a desktop and a laptop computer. Although the same parts are present in each, they are shaped and attached differently. For example, the keyboard from a desktop computer cannot fit into the keyboard space of a laptop computer.

The form factor design of hardware is dependent on, and influenced by, the form factor design of the components that go into the larger hardware unit. The size and the shape of the component are affected as are the connections and power specifications. Most component manufacturers have standardization rules so that components work together electrically and electronically and that they physically fit into the available space.

The standardization of component form factors includes the inability of incompatible components to physically fit into a space. For example, mini-USB receivers have a form factor that prevents micro-USB connectors from being inserted (and vice versa). The electric and electronic specifications of the two connectors are different and it could cause damage to other components or data if the wrong one were inserted.

A variety of cable connectors with different form factors

Computer memory

RAM is another example of a computer form factor that changes to prevent incompatible components from being inserted . Each generation of computer memory is made so that it cannot be inserted into a slot on a motherboard that was made for a different generation of memory. Because the electric and electronic specifications change for each generation of memory, inserting incompatible memory will, at best not work, and at worst, cause electrical damage to the motherboard or processor. If you want to upgrade or add memory to your computer, use the Crucial® Advisor™ tool or System Scanner tool to make sure you get compatible parts.

In addition to the different generations, there are different sizes and shapes of memory for different kinds of hardware. Servers, desktop computers, laptop computers, notebook computers, and mobile telephones all use different memory form factors. These form factors have both physically different sizes and different numbers and configurations of connection pins. Read more about other divisions in memory.

A diagram which indicates how the physical shape of memory has changed per generation

Solid state drives

The same concept exists for SSDs, as well. There are different sizes and connections for different generations of technology and different hardware applications. Read more about SSD form factors here.

Crucial solid state drives.


Motherboard form factors also vary in physical size and in the number and kind of electric and electronic connections. Motherboard form factors have been slower to change, but as significant new connections are developed, such as PCIe, the new technology is reflected in motherboards.

Motherboard form factors are designed for the size of the hardware unit and the number and kind of cards, drives, processors, and memory likely to be attached to that kind of a motherboard. The motherboards for desktop computers are almost always different than the motherboards for laptop computers.


If you want to upgrade your computer or buy a computer and upgrade it later, it's important to see what the component form factor is. This will ensure that you get new components that fit and work correctly.

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