Donaldson R F Screen PPI Calculator
Enter a screen’s resolution and size to get its pixel density, and see the physical dimensions and pixel size.
What PPI tells you
PPI (pixels per inch) is the diagonal length of the screen in pixels divided by its diagonal size in inches: √(width² + height²) ÷ diagonal. Higher PPI means smaller pixels and sharper text at the same viewing distance. As a rough guide, about 90–110 PPI looks fine on a desktop monitor, 140–220 PPI looks crisp on a monitor or laptop, and phones often exceed 400 PPI because they are held closer.
Screen sizes are quoted as the diagonal of the visible area; real dimensions can differ slightly, so treat the physical size as approximate. The example screens are typical sizes and resolutions, not exact specifications of any product.