Image Aspect Ratio Calculator
Given one dimension and a target aspect ratio, calculate the matching width or height.
About this tool
Given one known dimension and a target aspect ratio, this calculator instantly gives you the matching width or height — useful for planning crops, video exports, or print sizes without doing the math by hand.
How to use it
- Enter a known width or height.
- Enter or select the target aspect ratio (e.g. 16:9, 4:3, 1:1).
- Read the calculated matching dimension.
Tips
- Common ratios: 1:1 for square social posts, 16:9 for widescreen video/thumbnails, 4:5 for Instagram portrait posts.
FAQ
Does this resize an actual image file?
No, this is a calculator only — use the Image Resizer tool to actually resize a file to the dimensions you calculate here.