Coding & Dev
PPI Calculator
Calculate pixels per inch (PPI/DPI) for any screen or print output.
PPI (pixels per inch) measures screen sharpness. Higher PPI means crisper text and images. This is essential for UI/UX design, print production, and understanding screen quality specifications.
Pixel Density
82 PPI
- diagonal Px
- 2203 px diagonal
- quality
- Standard desktop
- aspect
- 1.7778:1 aspect ratio
Formula and method
PPI = √(Width² + Height²) / Diagonal
Pythagorean theorem to find diagonal pixel count, divided by physical diagonal in inches.
Worked examples
4K monitor 27"
- Width (px):
- 3840
- Height (px):
- 2160
- Diagonal Screen Size (inches):
- 27
Pixel Density: 163 PPI
iPhone 14 equivalent
- Width (px):
- 2532
- Height (px):
- 1170
- Diagonal Screen Size (inches):
- 6.1
Pixel Density: 457 PPI
Assumptions and limits
- Square pixels (1:1 pixel aspect ratio)
This tool provides an educational estimate. Rules, rates and personal circumstances can change the answer. Review the assumptions before relying on a result. Report a correction.
Common mistakes to avoid
- Using width or height instead of the diagonal — all screens are measured diagonally.
- Confusing DPI (for print) with PPI (for screens) — the terms are often used interchangeably but technically refer to different things.
Frequently asked questions
What PPI is Apple's Retina display?
Apple's Retina threshold is approximately 220 PPI at typical viewing distances. iPhone screens are 326-460 PPI. MacBook Retina is 220-254 PPI. At Retina density, the human eye cannot distinguish individual pixels at normal viewing distance.