Limits and SizesAn aspect ratio is the width divided by the height, written as two numbers. 16:9 means that for every 16 units of width there are 9 of height. The size in pixels can differ; the shape is what the ratio gives.
Finding a height for a width
Height = width x (second number / first number). For a 1080-pixel width at 16:9, the height is 1080 x 9 / 16 = 607.5, so 608 pixels. For 9:16, the height is 1080 x 16 / 9 = 1920.
Ratios you meet
| Ratio | Shape | Named by |
|---|---|---|
| 16:9 | Wide screen | YouTube standard on computers |
| 9:16 | Tall phone screen | Reels, Shorts |
| 3:4 | Tall photo | Instagram photo limit |
| 1.91:1 | Wide photo | Instagram photo and reel limit |
| 1:1 | Square | Safe within the Instagram photo range |
Cropping
To change the ratio you crop or add bars. Cropping loses the edges, so keep the subject in the middle. The resizer crops to the size you choose.