DIY Cost Tools
Screen Size Calculator
VIDEO CALCULATOR
Screen Size Calculator
Calculate pixel density, physical screen width and height, aspect ratio, and pixel diagonal from resolution and diagonal size.
How it works
Enter the native horizontal and vertical resolution plus the marketed diagonal screen size. The calculator uses the pixel diagonal to find pixels per inch and physical dimensions.
Formula
Pixel diagonal = √(width² + height²). PPI = pixel diagonal ÷ diagonal inches. Physical width = horizontal pixels ÷ PPI; physical height = vertical pixels ÷ PPI.
Worked example
A 1920 × 1080 display with a 24-inch diagonal is about 91.79 PPI, 20.92 inches wide, and 11.77 inches high, with a 16:9 ratio.
Important limits
- Advertised diagonal can be rounded and usually measures the viewable panel, not the bezel.
- Effective sharpness also depends on viewing distance, scaling, subpixel layout, and content.
- Resolution alone does not determine physical screen size.
Frequently asked questions
Is a higher PPI always better?
Higher PPI means smaller pixels at the same physical scale, but usefulness depends on viewing distance, operating-system scaling, and content.
Why is a 24-inch screen not 24 inches wide?
Screen size is measured diagonally. Width and height depend on the aspect ratio.
Sources and review notes
The calculation uses the Pythagorean theorem and the supplied native pixel dimensions. Last reviewed September 29, 2026.