Single board computers are oftentimes used because their compact size allows them to be installed in very small devices. Some of them are about the size of a credit card and others are much larger, even as large as standard desktop computers.

The dimensions of the single board computer are simply its physical dimensions. These are important for installing the computer in various types of cases or, in the case of consumer electronics, for installing them in branded types of cases, such as are seen used for routers and other components.

Single board computers are sometimes large enough to be installed in a standard computer case and sometimes small enough to fit in the palm of one’s hand. The dimensions sometimes make it possible to add a very small single board computer to an existing system to take up extra work or to expand the functionality of the system to which it is attached.