Aspect Ratio Calculator
Enter an aspect ratio and one known dimension to find the matching width or height in an instant. All calculation is done on your device.
How to calculate an aspect ratio
- Set the aspect ratio by typing a width and height, or click a preset such as 16:9.
- Type a known width or height in the Known Dimension section.
- The missing dimension updates automatically as you type.
- Copy the result or use it in your editor, camera or layout settings.
FAQs
What is an aspect ratio?
An aspect ratio is the proportional relationship between the width and height of an image or screen, written as width:height such as 16:9.
How do I find the missing dimension?
Divide the known dimension by its ratio value, then multiply by the other ratio value to get the missing width or height.
What is the 16:9 ratio used for?
The 16:9 widescreen ratio is used for most modern TVs, computer monitors, YouTube videos and phone screens.
Does the calculator round its results?
Yes. Results are rounded to two decimal places to keep them easy to read and quick to use.
Related Tools
Why use an aspect ratio calculator?
Use the Aspect Ratio Calculator when you need to size a video or image for a specific ratio like 16:9 without cropping, by finding the matching width or height.
- Size a video for 16:9 without cropping, so your footage keeps its full frame.
- Find the matching height or width for thumbnails, banners and social posts.
- Check that an image or screen fits a preset ratio such as 4:3, 3:2 or 9:16 before publishing.
Tips and Limits
The calculator ignores rotation and assumes a landscape orientation, so for a portrait video or image, swap the width and height inputs yourself.