Aspect-ratio & crop calculator
Find a source image’s exact ratio, calculate proportional dimensions and compare fit versus crop-to-fill. See centered crop losses without uploading an image.
How to use this tool
Replace the example values with your own, then choose Calculate image geometry. Changing an input clears the previous result until you calculate again. Copy the result or download a CSV to keep a record.
Method
Reduce source width and height by their greatest common divisor. Proportional height = target width × source height ÷ source width. Fit uses the smaller target/source scale factor; fill uses the larger. For fill, divide target dimensions by the fill factor to find the centered crop in source pixels.
Worked example
A 6000 × 4000 image has a 3:2 ratio. Fitting into 1080 × 1080 gives 1080 × 720 with 360 px of total vertical empty space. Filling the square retains a centered 4000 × 4000 source crop, removing 1000 source pixels from each side.
Assumptions and limits
This calculator provides geometry, not an image editor or file download. No photo upload is needed. It assumes square pixels and a centered crop; it cannot choose a composition. Fractional values need whole-pixel rounding in your editor. Enlarging dimensions does not create real detail.
Reference: Adobe: image size and resolution.