How to work out pixel density
- Choose Pixel density and type the screen’s resolution, such as 2560 x 1440, or tap a common one.
- Enter the Diagonal in inches or centimetres, as given in the specs.
- Read the PPI, the dot pitch and the screen’s width and height. Choose Width and height to get a screen’s dimensions from just its diagonal and aspect ratio.
Common screens
| Screen | Resolution | PPI |
|---|---|---|
| 24-inch monitor | 1920 × 1080 | 91.8 |
| 27-inch monitor | 2560 × 1440 | 108.8 |
| 34-inch ultrawide | 3440 × 1440 | 109.7 |
| 32-inch 4K monitor | 3840 × 2160 | 137.7 |
| 15.6-inch laptop | 1920 × 1080 | 141.2 |
| 27-inch 4K monitor | 3840 × 2160 | 163.2 |
| 13.3-inch laptop | 2560 × 1600 | 227.0 |
Pixel density and scaling
At high densities, text drawn at its normal pixel size gets too small to read, so operating systems scale it up, often by 150% or 200%. A 27-inch 4K monitor at 150% gives the same amount of space as a 1440p screen, with sharper text. When comparing screens, look at PPI and the scaling you’d use, not just the resolution. To check your own screen’s resolution, open what is my screen resolution; to work with aspect ratios, use the aspect ratio calculator.