Pixels Per Inch (PPI) Calculator
PPI measures the number of pixels per physical inch along the diagonal of a display.
How to use this calculator
- Enter integer horizontal and vertical resolution and the screen’s physical diagonal in inches.
- Check that every input uses the stated units and covers the same period, population or project scope.
- Change one assumption at a time when comparing scenarios.
Formula used by pixels per inch calculator calculator
PPI = √(horizontal pixels² + vertical pixels²) ÷ diagonal inches
- PPI = √(horizontal pixels² + vertical pixels²) ÷ diagonal inches
- PPI alone does not determine perceived sharpness; viewing distance, subpixel layout, scaling and eyesight matter.
- Inputs are validated against the tool-specific constraints; displayed results are rounded for readability.
Worked examples
Worked example
A 2560 × 1440 display with a 27-inch diagonal has a density of about 109 PPI.
The tool calculates diagonal pixel count, PPI and approximate pixel pitch.
The tool calculates diagonal pixel count, PPI and approximate pixel pitch.
Understanding the result
PPI measures the number of pixels per physical inch along the diagonal of a display.
PPI alone does not determine perceived sharpness; viewing distance, subpixel layout, scaling and eyesight matter.
Important notes
PPI alone does not determine perceived sharpness; viewing distance, subpixel layout, scaling and eyesight matter.
Treat the result as an estimate for the assumptions entered; verify important specifications against the relevant source or professional guidance.
Frequently asked questions
Is PPI the same as resolution?
No. Resolution is the pixel count; PPI relates that count to physical display size.
Is higher PPI always visibly better?
Visibility depends on viewing distance, content, scaling and the observer.
How should I use this result?
Enter integer horizontal and vertical resolution and the screen’s physical diagonal in inches.
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Learn the method behind the number or compare the terminology before using the calculator.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.