Check relation between the dp, px, sp, in, mm and pt measurement units and convert to other unit.
Android doesn't do direct pixel mapping, it uses Density Independent Pixel (dpi) values to scales the actual screen size
Screen density is area of pixel quantity or total count of pixels in the vertical and horizontal directions. This pixel area measurement is referred to as dpi(dots per inch). In Android, densities categorized in 6 types:ldpi (low) ~120dpi
There are other measurement units require for handling like images, graph, layout etc for android app development. In this tool you can compare measurement unit among different measurement unit values