Aspect Ratio Calculator

Reduce width and height to a ratio and calculate a matching scaled dimension.

Enter values

Original widthOriginal heightNew width (optional)New height (used when width is empty)

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Width and height are reduced with their greatest common divisor, so 1920×1080 becomes 16:9. Enter one target dimension to calculate the other.

Any consistent measurement unit can be used. Decimal output is formatted for readability.

What ratio is 1920×1080?

It is 16:9.

Does it work for portrait sizes?

Yes. 1080×1920 reduces to 9:16.

Does it resize an image file?

No. It calculates dimensions only.