Calculate aspect ratios and resize dimensions proportionally. Common presets for video, photos, and screens. Free online tool. This tool runs entirely in your browser — no data is sent to any server. It's fast, free, and works on any device.
Aspect ratio is the proportional relationship between width and height of an image or display. Getting it right is crucial for web design, video production, photography, and print media. Common ratios include 16:9 (widescreen video, most monitors), 4:3 (classic TV, presentations), 1:1 (Instagram square), 9:16 (vertical video, TikTok/Reels), and 3:2 (35mm photography). Using the wrong aspect ratio leads to stretched or cropped content. This calculator works both ways — enter dimensions to find the ratio, or enter a ratio and one dimension to find the matching dimension. Essential for responsive web design where images need to maintain proportions, video editors matching export settings, and designers preparing assets for multiple platforms.
1920×1080 is 16:9, the standard widescreen ratio used by Full HD monitors, YouTube videos, and most modern TVs. It's the most common ratio for video content today.
Instagram supports 1:1 (square, 1080×1080), 4:5 (portrait, 1080×1350, gets the most feed space), and 16:9 (landscape, 1080×608). Stories and Reels use 9:16 (1080×1920).
Lock the ratio by changing only one dimension — the other should scale proportionally. This calculator does that math for you. In CSS, use aspect-ratio: 16/9 or the padding-bottom percentage trick.
4:3 is the classic 'square-ish' format used by old TVs and many presentations. 16:9 is wider, giving more horizontal space — standard for modern screens. 16:9 content on a 4:3 screen shows black bars (letterboxing).
Most modern films use 2.39:1 (anamorphic widescreen). IMAX uses 1.43:1 or 1.9:1. These ultra-wide ratios are why movies often have black bars on 16:9 TVs.