Aspect Ratios for Social Media: A Cheat Sheet
Generate at the right ratio and stop cropping your best work. Every platform size, plus the framing tricks that make one image work in three places.
Cropping a 16:9 image to a 9:16 story throws away two-thirds of the frame — usually including the part you liked. Generate at the target ratio instead.
The sizes
- 4:5 — Instagram feed. The tallest allowed, so it occupies the most screen. Default to this.
- 9:16 — Reels, Stories, TikTok, Shorts.
- 1:1 — grids, product listings, profile-safe crops.
- 16:9 — YouTube thumbnails, website heroes, presentations.
- 3:2 — the classic photographic ratio; best for prints.
- 21:9 — cinematic banners and site headers.
Frame for two crops at once
Compose the subject in the central square and keep the outer edges as breathing room. A 16:9 image built this way survives a 1:1 crop intact. Add "generous margin around the subject, nothing important near the edges" to your prompt.
Leave room for the interface
Stories and Reels put controls over the top and bottom fifteen percent. Anything critical there — a face, a logo, a headline — will be covered. Prompt for "subject centred vertically with clear space at the top and bottom".
Generate wide, deliver narrow
If you need several formats, generate the widest one and use generative expand or outpainting for the rest. It is faster than re-rolling and keeps the lighting consistent across the set.
