PPI Calculator
Find the pixel density (pixels per inch) of a monitor, phone or tablet from its resolution and diagonal size, and see the matching dot pitch.
How it works
PPI is the diagonal pixel count divided by the diagonal size in inches: PPI = √(width² + height²) ÷ diagonal. Dot pitch is the physical distance between pixels: 25.4 ÷ PPI millimetres.
Frequently asked questions
What is the difference between PPI and DPI?
PPI describes pixels inside a digital image or screen. DPI describes dots a printer places on paper. They are often used interchangeably when discussing print resolution, but for displays PPI is the correct term.
What PPI is considered "Retina"?
Apple calls a display Retina when its pixel density is high enough that the eye cannot distinguish individual pixels at a typical viewing distance - roughly 300 PPI on a phone, 218 PPI on a laptop and 150-180 PPI on a desktop monitor.
Does higher PPI always mean a sharper image?
Within reason, yes. But a high-PPI screen with a low-resolution source image can look soft, and at very high densities the eye may not notice the difference from a normal viewing distance.