The proportional relationship of a video or image’s width to its height, expressed as W:H (e.g. 9:16, 1:1, 16:9).
Last verified · 2026-05-29 · by Moe Ameen
Aspect ratio determines how an image or video fits inside a platform's feed slot. The four ratios that matter for content creators: 9:16 (vertical, Reels/Shorts/TikTok/Stories), 1:1 (square, Instagram feed legacy), 4:5 (portrait, Instagram feed current), 16:9 (horizontal, YouTube/desktop).
Each platform has a preferred ratio and a tolerated set. Instagram feed accepts 1:1, 4:5, and 16:9 — but 4:5 occupies the most pixels in the feed and gets the most engagement per impression. Instagram Reels demands 9:16. LinkedIn accepts 16:9 video and 1:1 image but renders 1:1 largest on mobile.
Mismatched aspect ratios get letterboxed (black bars) or auto-cropped (subject offscreen). Either signals "lazy cross-post" to the algorithm and to viewers. Kompozy renders each output at the destination platform's native ratio per the persona's outlet config.
Aspect ratio is the proportional relationship of a video or image's width to its height, expressed as W:H — for example 9:16, 1:1, or 16:9. It determines how an image or video fits inside a platform's feed slot.
Four ratios matter: 9:16 (vertical, for Reels, Shorts, TikTok, and Stories), 1:1 (square, legacy Instagram feed), 4:5 (portrait, current Instagram feed), and 16:9 (horizontal, YouTube and desktop).
Instagram feed accepts 1:1, 4:5, and 16:9, but 4:5 occupies the most pixels in the feed and gets the most engagement per impression. Instagram Reels, by contrast, demands 9:16.
Mismatched aspect ratios get letterboxed with black bars or auto-cropped so the subject is offscreen. Either one signals a lazy cross-post to the algorithm and to viewers.
Kompozy renders each output at the destination platform's native ratio according to the persona's outlet config, so videos and images arrive sized correctly for each feed.