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Aspect Ratio Calculator

Reduce image or video dimensions to a ratio and calculate a proportional output size.

Processed on this device
Paste text or open a fileOr start from an example:
Waiting for input

Proportional size

The result appears here.

Ctrl+↵ copy result · Ctrl+Shift+F result to input

How it works

How to use Aspect Ratio Calculator

  1. Enter source dimensions as width × height.
  2. Set a target width.
  3. Read the reduced ratio and calculated height.
Frequently asked questions

Useful details

2 answers
How is height rounded?

To the nearest whole pixel, with a minimum of one pixel.

Does this resize a file?

This calculator gives dimensions. Use Image Resizer or Resize Video to process a file.

More help

Guides, common conversions and useful next steps.