Calculate new dimensions while keeping the same aspect ratio. Perfect for resizing images, video, and design work.
16:9 is the standard for HD and 4K video, YouTube, and most modern monitors (1920x1080, 2560x1440, 3840x2160). 4:3 was the old TV and monitor standard, still used in some presentations and iPad screens. 1:1 is a square, common for Instagram posts and profile pictures. 21:9 is ultrawide, used in cinema and ultrawide monitors. 9:16 is vertical video for TikTok, Instagram Reels, and YouTube Shorts. 3:2 is the standard for most DSLR photos and the Microsoft Surface. 5:4 is used in some older monitors and medium format photography.
The aspect ratio is the proportional relationship between width and height. A 16:9 ratio means for every 16 units of width, there are 9 units of height. When you resize an image or video while maintaining the aspect ratio, the proportions stay the same and nothing gets stretched or distorted. This calculator finds the greatest common divisor of your width and height to determine the simplest ratio.