How is aspect ratio calculated?

It simplifies the ratio of width to height (e.g. 1920×1080 simplifies to 16:9) using the greatest common divisor of the two numbers.

What is PPI and how is it calculated?

Pixels Per Inch measures screen sharpness, calculated as the diagonal resolution in pixels divided by the diagonal screen size in inches.

Why do my dimensions not match a "standard" ratio exactly?

Manufacturing tolerances and rounding mean real screens are very close to standard ratios like 16:9 or 4:3, but not always mathematically exact.

Screen Aspect Ratio & PPI Calculator

Find a screen's aspect ratio and pixel density from its resolution.

Width (pixels)

Height (pixels)

Diagonal Screen Size (inches, optional)

Aspect Ratio -

Diagonal Resolution -

Pixel Density (PPI) -

What Is the Screen Aspect Ratio & PPI Calculator?

The Screen Aspect Ratio Calculator simplifies a resolution like 1920×1080 into its ratio form (16:9), and can also calculate pixel density (PPI) if you provide the physical diagonal screen size.

Formula Used

Ratio = Width ÷ GCD(W,H) : Height ÷ GCD(W,H)
PPI = √(W² + H²) ÷ Diagonal (inches)

GCD is the greatest common divisor of width and height. PPI (pixels per inch) determines how sharp the image looks — higher PPI means a crisper display at normal viewing distance.

How to Use This Calculator

Enter the screen's horizontal resolution in pixels.
Enter the screen's vertical resolution in pixels.
Optionally enter the physical diagonal size in inches to also get PPI.
Click Calculate.

Worked Example

A 1920×1080 screen simplifies to a 16:9 aspect ratio. On a 24-inch diagonal monitor, the diagonal resolution is √(1920²+1080²) ≈ 2203 pixels, giving a pixel density of about 92 PPI.