Screen PPI Calculator

Enter the screen resolution and the diagonal size in inches to get the pixel density (PPI). A higher PPI means a sharper picture.

This result is an estimate only. Check with your bank or the relevant authority before making decisions.

How it is calculated

Diagonal in pixels = √(width² + height²)
PPI = diagonal in pixels ÷ diagonal in inches
Pixel pitch (mm) = 25.4 ÷ PPI
Megapixels = width × height ÷ 1,000,000

To get the shape of the screen, use the aspect ratio calculator.

Worked example

A 1920 × 1080 monitor with a 24 inch diagonal:

Diagonal in pixels: √(1920² + 1080²) = √4,852,800 = 2,202.9
PPI: 2,202.9 ÷ 24 = 91.8
Pixel pitch: 25.4 ÷ 91.8 = 0.277 mm

Why your number may differ

The advertised diagonal is often rounded, and curved or notched screens may be measured differently. Real viewing comfort also depends on distance, brightness and your eyesight, so use PPI as a guide only.

Frequently asked questions

What is PPI?

PPI is pixels per inch, the number of pixels packed into each inch of the screen. Higher PPI gives a sharper image at the same viewing distance.

What PPI is good enough?

It depends on viewing distance. A phone held close looks sharp at around 400 PPI or more, while a monitor viewed from arm’s length is usually fine from about 100 to 140 PPI.

Is PPI the same as DPI?

PPI describes a screen. DPI describes the dots a printer places on paper. People often mix them up, but they measure different things.