Aspect ratio calculator
Find the aspect ratio of an image, video or screen, or work out the size you need to keep its shape when resizing. Video editors, photographers and web designers use it often.
- Runs in your browser
- Free, no account needed
- Copy or download the result
Result
Example
Calculation: Width and height to ratio Width: 1920 Height: 1080 Ratio (for finding a side): 16:9
Aspect ratio: 16:9 Decimal: 1.7778:1 (width divided by height) Orientation: landscape Common name: 16:9 (widescreen HD video)
How to use the aspect ratio calculator
- Pick a Calculation: Width and height to ratio, Ratio and width to height, or Ratio and height to width.
- Fill in Width and Height, or the Ratio (for finding a side) and the one side you know.
- Press Run to see the ratio or the missing side.
- Press Copy result or Download to keep the answer.
How it works
Simplifying divides width and height by their greatest common divisor using exact whole number math, so 1920 by 1080 becomes 16:9. Decimals up to 10 places are allowed.
To find a side, the tool uses height = width / ratio or width = height x ratio, and also shows the nearest whole number.
The ratio field accepts 16:9, 16/9, 16x9 or a single decimal such as 2.39.
Results are matched to common ratios such as 1:1, 4:3, 3:2, 16:10, 16:9, 21:9, 4:5 and 9:16, and called close when within 3%. Zero, negative and malformed values are rejected.
Everything runs in your browser. Your input is not uploaded or stored.
Questions and answers
What is the aspect ratio of 1920 x 1080?
It is 16:9, the standard widescreen ratio for HD and 4K video.
Is 21:9 an exact ratio?
Not usually. Ultrawide screens such as 2560 x 1080 are really 64:27, about 2.37:1, and 21:9 is the marketing name. The tool reports them as close to 21:9.
How do I find the height for a 16:9 video?
Divide the width by 16 and multiply by 9. For a width of 1280 the height is 720. Choose Ratio and width to height to do it here.