How to Calculate Screen Size Calculator
What is Screen Size Calculator?
A screen size calculator computes a monitor's or TV's actual width, height, and pixel density (PPI) from the diagonal measurement and aspect ratio. It helps compare displays of different sizes and resolutions.
Step-by-Step Guide
- 1Use Pythagoras' theorem with the aspect ratio to derive width and height from diagonal
- 2For 16:9 aspect ratio: height = diagonal × 9 / √(16²+9²); width = height × 16/9
- 3PPI = √(horizontal pixels² + vertical pixels²) / diagonal inches
Worked Examples
Input
27-inch 16:9 monitor · 2560×1440 resolution
Result
23.5" × 13.2" · 109 PPI
QHD resolution at common desk size
Input
55-inch TV · 3840×2160 (4K)
Result
47.9" × 27" · 80 PPI
Typical living room 4K TV