The basic difference between desktop and laptop computers is that laptops are designed for portability. Laptops can easily be carried in a case or bag, while a desktop is typically set up on a desk, table or counter with the intention that it stay there for use.
A laptop is an all-in-one machine, with the screen, keyboard and mouse built into the device. Comparatively, desktops typically have a separate keyboard and mouse, and the central processing unit can be separate from the computer monitor. Laptops are typically designed to be around the size of a notebook when closed, so their components are smaller than the components used in desktop computers. As a result, a laptop often sacrifices performance for portability. An average desktop has more hard drive space, a faster central processor and better graphics performance than an average laptop with a standard hardware configuration.
Some high-end laptops have hardware specifications that allow them to approach or exceed the performance of some desktops. However, a desktop is ordinarily preferred for graphics-intensive uses, such as gaming.
One of the major differences between laptops and desktops is screen size. To preserve portability, laptop models rarely have a screen size that exceeds 15 to 17 inches. With a desktop, the user can incorporate a large screen of up to 27 inches or more and can even use multiple screens, since the computer system is permanently placed.