Free Aspect Ratio Calculator
This aspect ratio calculator helps you calculate a matching width or height while keeping the same image, video or design ratio. Enter an aspect ratio such as 16:9, 1:1 or 9:16, then add either width or height to calculate the missing size.
It is useful for thumbnails, YouTube videos, website images, social media posts, banners, print layouts, Canva designs and avoiding stretched images that look like they have had a rough day.
How To Use This Aspect Ratio Calculator
Enter the aspect ratio width and height, choose whether you already know the width or height, then enter the known size. The calculator will work out the missing dimension.
Common Aspect Ratios
Common ratios include 16:9 for widescreen video, 1:1 for square images and 9:16 for vertical video. Keeping the correct ratio helps avoid stretched, squashed or weirdly cursed images.
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Aspect Ratio Calculator FAQ
What is an aspect ratio?
An aspect ratio describes the relationship between width and height. For example, 16:9 means 16 units wide for every 9 units high.
Can I use this for YouTube thumbnails?
Yes. YouTube thumbnails commonly use a 16:9 ratio, such as 1280 x 720 pixels.
Can I use this for vertical videos?
Yes. Use 9:16 for vertical video sizes such as Shorts, Reels and TikTok-style layouts.