Screen PPI Calculator
Work out a screen's pixels-per-inch (PPI) from its resolution and diagonal size, plus its aspect ratio and physical dimensions.
Screen PPI Calculator
Results
- Pixel density
- 91.8 ppi
- Aspect ratio
- 16:9
- Physical size
- 20.9" × 11.8"
How to calculate screen pixel density (PPI)
Work out a screen's pixels-per-inch from its resolution and diagonal size, plus its aspect ratio and physical dimensions.
The formula
- Formula
PPI = sqrt(width_px² + height_px²) / diagonal_inches
How to use it
- Enter the screen's resolution in pixels (width and height).
- Enter the panel's diagonal size in inches.
- Read the pixel density, aspect ratio, and physical width/height.
What counts as a high PPI
Desktop monitors typically run 90–110 ppi. Phones marketed as "Retina" or high-DPI are usually 400–550 ppi, since they're held much closer to the eye. There's no universal "good" number — it depends on viewing distance.
Privacy
Runs locally in your browser. No data is sent to the server.
FAQ
What's the difference between PPI and DPI?
PPI (pixels per inch) describes a screen's pixel density. DPI (dots per inch) is the equivalent term for printers. They're often used interchangeably but technically describe different output devices.
Does a higher PPI mean a better screen?
It means finer detail and less visible pixelation at a given viewing distance, but overall image quality also depends on color accuracy, contrast, and brightness — PPI alone doesn't determine that.
Why does this need the diagonal size, not the width and height in inches?
Diagonal size is what manufacturers publish (e.g. "6.1-inch display"), so it's the number most people have on hand; the calculator derives the physical width and height from it.