16:9
Enter one side of the ratio to calculate the other
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Height
A handy utility for front-end developers and video editors. The Aspect Ratio Calculator helps you determine the correct dimensions to maintain a specific aspect ratio, whether for responsive design or video production. Calculate width and height proportions, work with any aspect ratio (16:9, 4:3, 1:1, etc.), and ensure your images and videos maintain proper proportions for any screen or platform.
An aspect ratio is the proportional relationship between width and height, written as width:height. A 16:9 frame is 16 units wide for every 9 units tall, whether that is 1920 x 1080 or 1280 x 720. Keeping the ratio fixed stops images and video from stretching when you resize them.
Multiply the width by the second number of the ratio, then divide by the first. For 16:9 at 1920 pixels wide, that is 1920 x 9 / 16 = 1080. The calculator does this for you and rounds to the nearest whole pixel.
16:9 is the standard for HD video, YouTube and most monitors, 4:3 suits older TVs and many tablets, and 1:1 fits square social posts. 9:16 is vertical video for Stories, Reels and TikTok, and 21:9 is ultrawide.
The boxes accept whole numbers only. For a ratio like 2.39:1, scale both sides up to whole numbers first, such as 239:100, and you get the same result. Calculated values are rounded to the nearest pixel.
Right in your browser. The maths runs locally as you type, so results update instantly with no button to press, and the tool is free to use without an account.
