Pixels, ratio, fps, and 300 MB
The Reels size that fills the player is 1080×1920. Instagram accepts anything from 9:16 to 1.91:1 as long as the short edge is at least 720 px, so a 16:9 file is legal and still the wrong shape.
Two limits surprise people coming from CapCut or an AI video tool: 30 fps is the Help Center minimum, and the publishing API rejects files over 300 MB. The in-app size cap is not published, so 300 MB is a warning.
MP4, MOV, WebM, or a thumbnail. Duration, resolution, aspect, fps, codec, and file size are read here. Nothing is uploaded.
Reels can run 20 minutes, but anything past 3 minutes is a poor bet for new audiences. The Help Center wants at least 30 fps.
269 top / 672 bottom / 65 left / 65 right
14% top, 35% bottom, 6% each side of a 1080×1920 frame (269 / 672 / 65 / 65), from Meta's Reels ads guide. The Help Center pages cover length and frame rate; the ads-guide percentages were recorded in the 2026-10-19 research pass and are also cited by https://postminion.com/blog/instagram-reels-length-and-size-limits.
Cited · 2026-10-19 · Instagram Help — Reels
No separate measured margin is stored for this platform.
1080×1920, 9:16, 30 fps, H.264, AAC. The short edge must be at least 720 px.
300 MB on the API. Instagram has not published the in-app limit. ClipLint warns above 300 MB.
Yes, up to 1.91:1. It will not be full screen. Wider than that fails the aspect window.