To send motion data into computers or other electrical devices, a trackball is used. It has a movable disk on top that can be moved in any direction, serving the same function as a mouse. Simply spin the movable ball on top of the trackball unit with your palm to create motion input instead of moving the entire device.

Computer trackballs are typically used to substitute mice and are mainly used to navigate the pointer on the screen. Similar to controllers, computer trackballs have keys that can be used as left- and right-click triggers as well as for other instructions. Trackballs can be found in other electrical devices besides computers, such as pinball games, mixing boards, and self-service booths, though they are most frequently used with computers. The trackballs on these gadgets are frequently bigger than those found on computer entry devices.

Trackballs are superior to mice in a number of ways, in addition to having the ability to be integrated into different devices. The compact size (since they don't need a mousepad or a big space to move the mouse), fingertip control (which might give more precision), and enhanced comfort are some benefits (since there is less strain on the wrist). However, because they feel less natural and may take some getting used to, many people find trackballs to be more difficult to use than computers. Because of this, the usual entry method on the overwhelming bulk of PCs is a mouse rather than a trackball.