Calculate pixel density, screen dimensions, and resolution. Enter any two values to compute the rest.
PPI Calculation Formulas
Mathematical foundations for pixel density and display dimension calculations.
- HD: 1280 × 720 (720p)
- Full HD: 1920 × 1080 (1080p)
- QHD: 2560 × 1440 (1440p)
- 4K UHD: 3840 × 2160 (2160p)
- 5K: 5120 × 2880
- 8K UHD: 7680 × 4320
Understanding PPI
Learn about pixel density, its impact on display quality, and how to choose the right PPI for your needs.
PPI (Pixels Per Inch) measures how many pixels fit into one linear inch of a display. Higher PPI means more pixels are packed into the same space, resulting in sharper images and text.
PPI is calculated by dividing the diagonal pixel count by the diagonal physical size in inches. It’s a key metric for evaluating display sharpness.
Apple’s “Retina” display refers to screens where individual pixels are indistinguishable at typical viewing distances. This generally means 300+ PPI for handheld devices and 220+ PPI for laptops.
HiDPI (High Dots Per Inch) is a similar concept used across platforms. Modern operating systems use UI scaling to maintain readable interface sizes on high-PPI screens.
The required PPI depends heavily on viewing distance. A 4K TV at 10 feet doesn’t need as high PPI as a smartphone held 12 inches away, because angular resolution matters more than absolute PPI.
For most users, 110+ PPI at arm’s length (desktop monitors) provides a good experience. Closer devices like phones benefit from 300+ PPI for truly sharp text and images.
Pixel pitch is the center-to-center distance between adjacent pixels, usually measured in millimeters or micrometers. Lower pixel pitch means higher PPI and sharper images.
Professional monitors for photo/video editing typically have pixel pitches around 0.2-0.3mm. LED video walls for events might have 1-10mm pitch depending on viewing distance.