How is the aspect ratio simplified?

It divides both the original width and height by their greatest common divisor (GCD), so 1920×1080 becomes 16:9.

Do I enter both a new width and height?

No — enter just one. Filling the new width clears the height (and vice versa), and the tool computes the missing value to preserve the ratio.

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Aspect Ratio Calculator

Work out width or height for an aspect ratio.

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How to use the Aspect Ratio Calculator

1Enter the original width and height to define the ratio.
2Type a new width OR a new height — leave the other blank.
3Read the calculated dimension and simplified ratio, then copy.

About the Aspect Ratio Calculator

Free aspect ratio calculator: enter original width and height, then a new width or height to compute the missing dimension and see the simplified ratio like 16:9.

Part of our Calculators collection. Browse all tools.

Frequently asked questions

How is the aspect ratio simplified?: It divides both the original width and height by their greatest common divisor (GCD), so 1920×1080 becomes 16:9.
Do I enter both a new width and height?: No — enter just one. Filling the new width clears the height (and vice versa), and the tool computes the missing value to preserve the ratio.