How Aspect Ratios Work
An aspect ratio expresses the proportional relationship between width and height. It is written as W:H (e.g. 16:9). The ratio is simplified using the Greatest Common Divisor (GCD).
Common Standard Ratios
- 16:9: Global standard for YouTube, HDTV, widescreen monitors, and presentations (1080p, 1440p, 4K UHD).
- 9:16: Vertical full-screen video format for TikTok, Instagram Reels, and YouTube Shorts.
- 4:3: Traditional TV broadcast, older computer monitors, iPad displays, and medium format photography.
- 1:1: Square images for social media feeds, avatars, and album art.
- 21:9: Cinematic anamorphic video and ultrawide curved monitors.