21:9 Aspect Ratio Calculator
Use this 21:9 aspect ratio calculator for ultrawide monitors, cinematic video crops, website banners, and wide display layouts. It also covers 21 by 9, 21x9, and ultrawide resolution searches.
Aspect Ratio
64:27
Resolution
2560×1080
Display
Photo
Video
Social
64:27
How to calculate 21:9 dimensions
For 21:9, width is 21 units for every 9 units of height. To calculate height, multiply width by 9 and divide by 21. To calculate width, multiply height by 21 and divide by 9.
Common pixel sizes
- 2560x1080
- 3440x1440
- 3840x1600
- 5120x2160
- 6880x2880
Where 21:9 is used
- Ultrawide monitors
- Cinematic website and product banners
- Film-style video crops
- Game capture and streaming layouts
- Wide timeline and editing workspaces
21:9 calculation examples
Frequently asked questions
What resolution is 21:9?
Common ultrawide resolutions include 2560x1080, 3440x1440, 3840x1600, and 5120x2160. Some are marketed as 21:9 even when the simplified ratio is slightly different.
Is 3440x1440 exactly 21:9?
No. 3440x1440 is very close to 21:9, but it simplifies to 43:18. It is still commonly sold and searched as ultrawide 21:9.
How do I calculate a 21:9 video height?
Multiply the width by 9, then divide by 21. For example, 2520 wide becomes 1080 high.