Aspect Ratio Calculator

An aspect ratio expresses the proportional relationship between an image's width and height. Written as width:height (e.g., 16:9), it describes the shape of the frame regardless of actual pixel dimensions. A 16:9 ratio means the width is 1.78 times the height — whether the image is 1920×1080, 1280×720, or 3840×2160, the proportions remain identical. Common aspect ratios each serve specific purposes: 1:1 (square) is standard for profile pictures and product thumbnails. 4:3 is the traditional photo and older TV format. 16:9 is the modern widescreen standard for video, presentations, and monitors. 9:16 (vertical) is optimized for mobile-first content like Instagram Stories and TikTok. 21:9 is the ultra-wide cinematic format. 3:2 is the standard 35mm film and DSLR photo ratio. Knowing your target aspect ratio is essential before cropping or resizing images, as changing aspect ratio after content creation often means losing important parts of the composition. This calculator helps you determine the correct dimensions while maintaining your desired proportions.

Each major platform has specific aspect ratio requirements that affect how content displays. Instagram supports 1:1 (square feed posts), 4:5 (portrait feed posts — maximum vertical space), and 9:16 (Stories and Reels). YouTube uses 16:9 for standard videos and thumbnails (1280×720 recommended). TikTok is exclusively 9:16 vertical video. Twitter/X supports images up to 16:9 in the feed, displaying square and portrait images with cropping. LinkedIn prefers 1.91:1 for link preview images and 1:1 for feed posts. Facebook uses 1.91:1 for link previews and supports various ratios in feed. Pinterest favors 2:3 vertical pins (1000×1500px) for maximum visibility in the pin feed. For display advertising, standard IAB sizes include 300×250 (6:5), 728×90 (approximately 8:1), and 160×600 (4:15). When creating content for multiple platforms, design at the largest needed resolution and crop to different ratios for each platform using this calculator to determine exact pixel dimensions.