How it works
Calculate the PPI (Pixels Per Inch) and evaluate the sharpness of any display based on resolution and size.
Input query strings and outputs
Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.
Input query strings
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?width=Width (px)Number · Optional · Default: 1,920
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?height=Height (px)Number · Optional · Default: 1,080
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?inches=Diagonal Size (inches)Number · Optional · Default: 24
Outputs
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resultResultText · Primary output
result contains the calculator’s complete rendered result area, including its visible result cards, tables, charts, and messages.
Calculate the sharpness of your display in Pixels Per Inch
Description
The Pixel Density Calculator is a technical tool for tech enthusiasts, designers, and gamers. It measures the concentration of pixels on a screen, expressed as PPI (Pixels Per Inch). Higher PPI means a “sharper” image where individual pixels are harder to see with the human eye. By entering the screen’s resolution and its diagonal size, this tool calculates the exact density.
Inputs
- Width (px): The horizontal resolution (e.g., 1920).
- Height (px): The vertical resolution (e.g., 1080).
- Diagonal Size (inches): The screen size measured corner-to-corner.
Outputs
- Pixel Density: The calculated PPI.
Chart
- N/A: This tool provides precision numeric technical results.
“Good to Know”
- Retina Displays: Apple coined the term “Retina” for displays where the human eye cannot distinguish pixels at a typical viewing distance—this usually happens above 300 PPI for phones.
- Resolution vs. Size: A 24-inch 1080p monitor actually looks less sharp than a 15-inch 1080p laptop because the same number of pixels are stretched over a larger area.
- The Formula: Uses the Pythagorean theorem to find the diagonal pixel count, then divides by the physical diagonal inches: $PPI = \frac{\sqrt{w^2 + h^2}}{d}$.
Examples
Example 1: Standard Desktop Monitor
- Input: 1920x1080, 24 inches
- Output: 91.79 PPI
Example 2: Modern Smartphone
- Input: 1170x2532, 6.1 inches
- Output: 459.73 PPI
Example 3: 4K Workstation
- Input: 3840x2160, 27 inches
- Output: 163.18 PPI