Numbers and measurement
Aspect ratio and resize calculator
Simplify a width-to-height ratio and calculate a matching width or height for proportional resizing without cropping.
Runs in your browser. Inputs stay on this page and are not uploaded or added to the URL.
Your result
How to use this tool
Enter a positive width and height to simplify the aspect ratio. Then supply a new width or new height to calculate the other dimension while preserving the same proportions. Keep all dimensions in the same unit.
The reduced ratio uses exact finite-decimal arithmetic. The calculated dimension is shown to up to 12 significant digits and rounded to a whole pixel separately; rounding may slightly change the final pixel ratio. This tool does not crop, pad or modify an image.
Worked example
1920 × 1080 reduces to 16:9. At a new width of 1280, the matching height is 720.
References and method
Contifield is an independent utility site. Reference publishers do not endorse this tool.
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