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Aspect Ratio Calculator
Enter any two dimensions to calculate the third while preserving the aspect ratio. Perfect for resizing images, videos, and UI elements.
Frequently Asked Questions
An aspect ratio is the proportional relationship between the width and height of an image or screen, expressed as two numbers separated by a colon (e.g., 16:9). It determines the shape of the rectangle without specifying its actual size.
YouTube recommends 16:9 for standard landscape videos. Portrait (9:16) and square (1:1) formats are supported for Shorts. The recommended minimum resolution is 1280×720 for HD quality.
Use the CSS property
aspect-ratio: 16 / 9 on modern browsers, or the classic padding-top trick: set padding-top: 56.25% on a relative-positioned container (56.25% = 9/16 × 100%).