Aspect Ratio Calculator
Find the aspect ratio of an image or video, or work out a missing width or height from a ratio such as 16:9.
Your result
Enter the width and the height to see the ratio.
How to use it
- Choose what you want to find.
- Enter the width and the height, or the ratio and one side.
- Read the result and copy it.
Examples
- Ratio of 1920 × 10801920 × 1080 16:9
- Height for a 1280 width at 16:91280 ÷ 16 × 9 720
- 1920 × 1080 inside an 800 × 800 frame1920 × 1080 800 × 450
Tool details and privacy
Enter a width and a height to get the simplified aspect ratio, such as 16:9. It also finds a missing width or height from a ratio you know, and the size of an image inside a frame without stretching it.
The simplified ratio is the width and the height divided by their greatest common divisor.
Options
- Three calculations: the ratio, a missing side, and a fit inside a frame.
- The nearest common ratio is shown when the exact ratio is not two small numbers, such as 1366 × 768 ≈ 16:9.
Limits
- Numbers must be above 0 and up to 1000000.
- A missing side is rounded to four decimal places, and a fitted size to two.
- The nearest common ratio is shown when the size is within 1% of it.
- It works with numbers only. It does not open or crop an image.
Privacy
The numbers are calculated in your browser and are not sent to any server.
Questions
What is the aspect ratio of 1920 × 1080?
16:9, the usual ratio for computer screens, televisions and YouTube video.
How do I work out the height from a width and a ratio?
Divide the width by the first number of the ratio and multiply by the second. For a 1280 width at 16:9: 1280 ÷ 16 × 9 = 720.
What does fitting inside a frame mean?
Scaling the image up or down until all of it sits inside the frame at its own ratio, with no cropping or stretching.
Why do I get a ratio such as 683:384?
Because 1366 × 768 does not reduce to two small numbers. The calculator shows the nearest common ratio beside it, which is 16:9.