Pixels per inch

Pixels per inch (PPI) is a measurement of the resolution of a computer display, related to the size of the display in inches and the total number of pixels in the horizontal and vertical directions. This measurement is often referred to as dots per inch, though that measurement more accurately refers to the resolution of a computer printer.

Typical circa-2000 cathode ray tube computer displays are generally capable of 72 to 130 pixels per inch. For example, a display that is 11 inches wide by 8.5 inches high, capable of a maximum 1024 by 768 pixel resolution, can display about 93 PPI in both the horizontal and vertical directions. This figure is determined by dividing width (or height), in pixels, by width (or height) in inches. It is possible for a display's horizontal and vertical PPI measurements to be different.

See also: dots per inch, samples per inch