How it works
The width-to-height ratio is reduced by the greatest common divisor. The missing dimension keeps the ratio and rounds to the nearest pixel.
Images / HXD Labs
Aspect ratio calculator
Resize an image, video or screen without stretching its original proportions.
Result
Fill in the fields to see the result.
How to use
Choose a common-dimensions preset or enter the original width and height. Set a new width or height to calculate the matching dimension; the result is rounded to the nearest pixel when needed.
Example
A 1920 × 1080 image has a 16:9 ratio. At 1280 px wide, the proportional height is 720 px.
Good to know
Rounding to whole pixels can slightly change the exact ratio. This tool calculates dimensions but does not edit the image file.