Screen PPI Calculator
Work out a screen's pixels per inch and pixel density from resolution and screen size to compare monitors and phones, free in your browser.
Enter Values
Minimum 1
Minimum 1
Minimum 0
How to use this calculator
- Enter the width and height in pixels and the diagonal in inches.
- Read the PPI and dot pitch.
How it works
PPI = √(width² + height²) ÷ diagonal — the diagonal pixel count divided by the diagonal in inches.
Worked example
1920×1080 on 15.6". ≈ 141 PPI.
Common mistakes
- Using the visible area diagonal vs the advertised size — they can differ slightly.
- Entering centimetres for the diagonal instead of inches.
Frequently asked questions
How is PPI calculated?
PPI = √(width² + height² in pixels) ÷ diagonal in inches. A 1920×1080 screen at 15.6 inches is about 141 PPI.
Why does PPI matter?
Higher PPI means sharper text and images; at typical viewing distances, displays above roughly 200–300 PPI look pixel-free.
What's a good PPI?
Phones are often 400+ PPI; laptops around 130–220; desktop monitors 90–160. Higher PPI looks sharper.
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Explore more in Units, Measurement & Converters.
Cite this tool
Zerdly. (2026). Screen PPI Calculator. Retrieved from https://www.zerdly.com/tools/screen-ppi-calculator/
Tip: Enter any known values to calculate the remaining results.
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