calculateppi.com
Free screen density calculator

Calculate any screen's pixel density.

Enter resolution and screen size — get PPI, density classification, Retina estimate, dot pitch, and viewing distance. Private, instant, runs in your browser.

PPI Calculator

√(W²+H²) ÷ size — precise to 0.1 PPI
Unit:
in
Use the diagonal printed on the box or spec sheet.
PPI
StandardHighUltra HighRetina

Retina estimate
Dot pitch
Total pixels
Aspect ratio
Megapixels
Min. view distance
PPI = √(W² + H²) ÷ diagonal · Retina-class estimate ≥ 300 PPI (approximate; depends on viewing distance)

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Frequently asked questions

What is PPI?

PPI (Pixels Per Inch) measures how many pixels fit into one inch of a screen. Higher PPI means a sharper, more detailed image because pixels are packed denser.

How is PPI calculated?

PPI = √(width² + height²) ÷ diagonal in inches. For example, a 1920×1080 screen with a 15.6-inch diagonal has a PPI of about 141.6.

What is a good PPI for a phone?

Most modern phones range from 400 to 500+ PPI, which is well above the point where the human eye sees individual pixels at typical viewing distance.

What PPI is considered Retina?

Apple's Retina concept depends on viewing distance, but a common rule-of-thumb is ~300 PPI or higher at typical phone/tablet distance qualifies as Retina-class. For laptops and desktops viewed from farther away, ~200 PPI can already look perfectly sharp.

PPI vs DPI — what's the difference?

PPI (pixels per inch) refers to screens and digital displays. DPI (dots per inch) refers to printers and physical ink dots. They are related but not interchangeable.

How do I calculate PPI from inches and resolution?

Enter your screen's diagonal in inches and its resolution (width × height in pixels) into the calculator above — it computes PPI instantly, with no page reload.