How to calculate screen dimensions
Use the diagonal, aspect ratio and resolution.
1
Enter the diagonal
Screen sizes are quoted as the diagonal in inches.
2
Choose the aspect ratio
The ratio determines how much of the diagonal goes to width and height.
3
Add the resolution
The horizontal pixel count gives the pixel density in PPI.
What does this tool do?
A screen’s diagonal and aspect ratio determine its actual width and height. Adding the horizontal resolution gives the pixel density, which is useful when comparing monitors at different sizes.
The Formula
Width = diagonal × w ÷ √(w² + h²); height = diagonal × h ÷ √(w² + h²); PPI = pixel width ÷ width (in)Frequently Asked Questions
What is the width of a 27-inch 16:9 monitor?
About 23.5 inches (59.7 cm) wide and 13.2 inches (33.6 cm) tall, excluding the bezel.
What does PPI mean?
Pixels per inch. Higher PPI means sharper text and images at the same viewing distance. It is calculated from the pixel width divided by the physical width.