PPI Calculator
Calculate screen pixels per inch from resolution and diagonal size. Built for mobile and tablet QA.
Pixels per inch (PPI)
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ppi
Formula: PPI = √(width² + height²) ÷ diagonal inches. Compare results with our Mobile Device Sizes reference for common phones and tablets.
What is PPI?
PPI (pixels per inch) measures how densely pixels are packed on a display. Higher PPI means sharper text and UI at a given viewing distance. Mobile QA teams use PPI with logical resolution and scale factor when validating layouts across phones and tablets.
How to use this calculator
Enter the physical screen width and height in pixels, plus the diagonal screen size in inches. The PPI updates live. Use values from a device spec sheet or from our Mobile Device Sizes reference page.
Mobile QA use cases
Verify marketing screenshots match target device sharpness. Compare emulator density settings against real hardware specs. Document expected PPI when filing visual defects on high-DPI displays. Plan responsive breakpoints with physical size context, not pixels alone.
PPI vs DPI
PPI applies to screens. DPI (dots per inch) usually applies to print or raster images. For print DPI, use our DPI Calculator. For phone and tablet displays, PPI is the correct term.
