🔍 PPI Calculator (Pixels Per Inch)
Enter your screen’s resolution and diagonal size to calculate its pixel density (PPI), a key measure of display sharpness.
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What Is PPI?
Pixels Per Inch (PPI) measures how densely a screen’s pixels are packed together — a higher PPI generally means sharper text and images, since more detail is packed into the same physical space.
How It’s Calculated
The calculator first finds the diagonal resolution in pixels using the Pythagorean theorem: diagonal pixels = sqrt(width^2 + height^2). Dividing that by the physical diagonal screen size in inches gives the pixel density: PPI = diagonal pixels / diagonal inches.
Why It Matters
- Smartphones typically range from about 300-500 PPI, while desktop monitors commonly fall between 90-150 PPI, and this is why phone screens can look sharper up close.
- PPI is a physical display property, distinct from DPI (dots per inch), which usually refers to print resolution.
- This figure is useful for comparing display sharpness and for design or print-resolution planning.
Last reviewed August 2026