Aspect Ratio Calculator
Find the aspect ratio of any size, or calculate the missing width or height for a ratio.
Size → ratio
Ratio → missing dimension
What is aspect ratio?
Aspect ratio is the ratio of an image's width to its height. A 1920×1080 video is 16:9, a classic photo 3:2, an Instagram portrait post 4:5 and a phone story 9:16.
Two ways to use it
- Enter width and height to see the simplified ratio and the nearest standard ratio
- Enter a ratio and one dimension to calculate the other (e.g. 720 height for 1280 width at 16:9)
Where it helps
A handy helper for export settings, resizing images, embedding responsive videos and choosing CSS aspect-ratio values.
How to use Aspect Ratio Calculator
- Enter the width and height you know, or pick a ratio.
- Choose the calculation mode.
- The result updates as you type.
- Use the values in your design or video settings.
Why use this tool?
Does the maths you need to scale images and videos without distortion in seconds.
FAQ
Why isn't 1366×768 exactly 16:9?
Some common screen sizes are only approximately 16:9; the tool shows the exact ratio and the nearest standard one.
What ratio do YouTube Shorts need?
Shorts, Reels and TikTok use vertical 9:16 (e.g. 1080×1920).
What is 21:9?
A wide ratio used on ultrawide monitors and in cinematic video.
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