PPI / DPI Calculator
Work out a screen's pixel density (PPI) from its resolution and diagonal size in inches. It also shows the dot pitch — the physical size of one pixel.
How to use
Enter the horizontal and vertical resolution in pixels and the diagonal size in inches, or tap a preset. PPI is the pixel diagonal divided by the screen diagonal.
Higher PPI means a sharper display. Use it to compare monitors, laptops and phones, or to check if a screen is 'retina' at your viewing distance.
FAQ
What is PPI?
Pixels per inch — how many pixels fit in one inch of screen. Higher PPI looks sharper because pixels are smaller and harder to see.
Is PPI the same as DPI?
For screens the terms are used interchangeably. DPI (dots per inch) technically refers to printing, but people often mean PPI for displays.
How is it calculated?
PPI = √(width² + height²) in pixels ÷ diagonal in inches. This tool does it for you and also shows the dot pitch in mm.
What PPI is 'retina'?
Roughly 300+ PPI for phones at typical viewing distance, less for monitors held farther away. It depends on how close you sit.