PPI Calculator

Calculate the pixel density of any screen

Enter a display’s horizontal and vertical resolution in pixels along with its diagonal size in inches, and this tool returns its pixel density in PPI (pixels per inch) and the matching dot pitch in millimetres. Pixel density is found by taking the diagonal pixel count — the hypotenuse of the width and height — and dividing it by the diagonal screen size. A pick-list of common resolutions (720p through 8K) fills in the width and height for you so you only need to type the screen size.

PPI describes how tightly packed the pixels are: higher numbers mean sharper, finer detail. A 27-inch 1440p monitor sits around 109 PPI, a 15.6-inch 1080p laptop around 141 PPI, and modern phones often exceed 400 PPI. Dot pitch is the same information expressed as the distance between neighbouring pixel centres, so a higher PPI gives a smaller dot pitch.

FAQ

Is PPI the same as DPI? They are often used interchangeably for screens, but strictly PPI (pixels per inch) describes displays while DPI (dots per inch) describes printers. The arithmetic is identical, so this calculator works for both when you mean a screen’s pixel density.

What is a good PPI for a monitor? Roughly 90–110 PPI is comfortable for a desktop monitor at normal viewing distance, while laptops and phones benefit from 200 PPI or more because you sit closer to them.

What is dot pitch? Dot pitch is the centre-to-centre distance between two adjacent pixels, usually given in millimetres. It is the inverse of pixel density: 25.4 divided by the PPI, since there are 25.4 millimetres in an inch.