Aspect Ratio & Resize Calculator

No. It calculates dimensions and ideal fit/crop geometry without uploading a file. Copy the plan and use an image or video editor for the actual export.

The tool divides both dimensions by their greatest common divisor. For example, 1920:1080 becomes 16:9, and 21:9 becomes 7:3. These reduced ratios describe the same shape.

Enter source width and height, then choose a target width or height. The calculator scales both sides proportionally and rounds the result to whole pixels, with at least one pixel per side.

Pixel dimensions must be whole numbers. A proportional result such as 100 × 56.25 is rounded, which can change the ratio slightly. The tool shows the ratio difference; very small dimensions can change it substantially.

Fit uses the largest proportional size that fits entirely inside the target box and adds centered padding. Crop scales to cover the box and removes a centered part of the source outside it. The crop plan reports the retained source area.

They describe ideal centered geometry. An image editor may round or adjust coordinates to whole pixels. Check the edited output; the calculator does not guarantee a particular editor’s rounding policy.

Dimensions use whole pixels from 1 to 1,000,000 per side. Scale percentages range from 0.01 to 10,000%. These are planning limits; the website’s image and GIF editors have lower processing and output limits.

No. Calculation and the preview diagram run locally, and dimensions are not saved automatically. Copy or download is an explicit action.

The diagram keeps the target box’s proportions. Extremely wide or tall shapes appear thin, even though the numeric plan remains available. Fit/crop geometry is clipped to the target box.