What is Pixel Density

Number of pixels per unit area is called pixel density. Pixel density is a matric telling of how many pixels there are in fixed area of a display. It is very important metrics because it lets us know how closely packed the pixel on a display area. This is something that determines the quality, clarity and readability of the image displayed. It is usually measured in a unit called pixels per inch (ppi). If a screen of size 4 inch by 3 inch and of resolution 800*600 then pixel density is, Pixel Density (PD) = 800/4 * 600/3 = 200*200 If we have two displays with the same resolution, a smaller one will have the higher pixel density. And if we have displays with the same size, the one with a higher resolution will have the higher pixel density. So it's clear that the two parameters that we need in order to calculate the pixel density are displayed size and resolution. We can calculate the pixel density knowing the resolution and size (diagonal) or display as below