Screen Aspect Ratio Calculator
Reduce a pixel width and height to the simplest whole-number ratio and calculate the diagonal in pixels.
How to use this calculator
- Enter integer pixel width and height values.
- Review the worked example for screen aspect ratio calculator and compare the inputs with your own units.
- Change one assumption at a time and recalculate if you need a second scenario.
Aspect ratio and diagonal
Simplified ratio = width ÷ GCD(width,height) : height ÷ GCD(width,height); diagonal = square root(width² + height²).
- The ratio describes raster dimensions and is independent of physical display size.
- The result is calculated from the values entered; the page does not independently verify assumptions, data quality or real-world suitability.
Worked examples
A 1920 × 1080 image
The greatest common divisor of 1920 and 1080 is 120. Dividing each dimension by 120 gives 16:9.
1920/120 : 1080/120 = 16:9; diagonal ≈ 2202.9 pixels.
The image ratio is 16:9, in landscape orientation.
Understanding the result
A reduced ratio makes it easier to compare images and frames with different resolutions.
Pixel dimensions do not determine physical inches without a pixel density, and some video systems use non-square pixels.
Important notes
Check the export preset and target platform when preparing media.
Displayed figures are rounded for readability. Preserve more precision during intermediate calculations and verify the labels and units before using the estimate.
Frequently asked questions
What does the Screen Aspect Ratio Calculator show?
A reduced ratio makes it easier to compare images and frames with different resolutions.
What assumptions should I check?
Check the export preset and target platform when preparing media.
Does this replace expert or authoritative guidance?
Pixel dimensions do not determine physical inches without a pixel density, and some video systems use non-square pixels.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.