Aspect Ratio Guide for Images and Video
Calculate matching dimensions and resize media without accidentally stretching the picture.
This guide focuses on the practical decisions that matter when completing this task. Use it with the related GetTools utility, and always review the output before using it in an important workflow.
What aspect ratio means
Aspect ratio compares width with height. A 16:9 image is wider than it is tall, while 1:1 is square.
Preserve proportions when resizing
If you change only width or height and calculate the other dimension from the same ratio, the image keeps its shape. Entering unrelated dimensions can stretch or squash the content.
Common ratios
1:1 is common for square graphics, 4:3 for traditional photos and displays, 3:2 for many cameras, and 16:9 for widescreen video. Platforms can use different recommended sizes even when ratios match.
Calculate a missing dimension
For a ratio W:H, new height equals new width × H ÷ W. New width equals new height × W ÷ H. Round to whole pixels when required.
Cropping versus resizing
Resizing changes dimensions while preserving all content. Cropping removes outer areas to fit a different ratio. Decide which result you need before editing.
Check destination requirements
Advertising systems, social networks, marketplaces and print services may specify both a ratio and minimum pixel dimensions. Meet both requirements.
Quick checklist
- Confirm the destination requirements before you start.
- Keep an original copy when changing files or established URLs.
- Review the generated result rather than assuming automation is perfect.
- Use the related GetTools utility for the mechanical step, then make the final human check.