Tech
PPI Calculator (Pixels Per Inch)
Calculate pixel density (PPI) from screen resolution and diagonal size. Also derives physical screen dimensions, pixel pitch, dpcm, and aspect ratio.
PPI calculator
Common screens
Corner-to-corner screen size, the same number on the box.
Pixel density
461.44 PPI
Retina-class
Diagonal (pixels)
2,814.81 px
Diagonal (inches)
6.1 in
Physical width
5.5391 in
Physical height
2.555 in
Density (metric)
181.67 dpcm
Pixel pitch
0.055 mm
Aspect ratio
284:131
Frequently Asked Questions about the PPI Calculator (Pixels Per Inch)
What is PPI?
PPI (pixels per inch) measures how densely pixels are packed on a screen. Higher PPI means sharper text and images at the same viewing distance.
How is PPI calculated?
Take the diagonal in pixels, sqrt(width^2 + height^2), then divide by the screen's diagonal in inches. For 1920x1080 on a 24-inch monitor that comes out to about 91.8 PPI.
What counts as a Retina-class display?
Anything above roughly 300 PPI is hard to distinguish individual pixels at normal phone or tablet viewing distance. This calculator labels it Retina-class above 300, High-density 200-300, Standard 100-200, and Low-density under 100.
Why does my screen quote a different PPI than this calculator?
Manufacturers usually round to the nearest 5 or 10. Apple's 460 PPI for the iPhone 15 Pro, for example, is the exact 461.4 from 2556x1179 on a 6.1-inch panel rounded down.
Is PPI the same as DPI?
For displays, yes, they're used interchangeably. DPI technically belongs to print (dots of ink per inch); PPI belongs to screens (pixels per inch). The math and the units are identical.