An Instagram Reel can be between 3 seconds and 15 minutes long, with a maximum file size of 300 MB. That is the figure in Meta’s own media documentation for the Instagram API, which is the most reliable source available because it is the specification Instagram’s own publishing pipeline enforces.
Instagram Reels specs
| Spec | Value |
|---|---|
| Minimum duration | 3 seconds |
| Maximum duration | 15 minutes |
| Maximum file size | 300 MB |
| Recommended aspect ratio | 9:16 |
| Accepted aspect ratio range | 0.01:1 to 10:1 |
| Caption | Up to 2,200 characters |
| Hashtags | 30 |
| @ mentions | 20 |
Note: Figures here were verified against Meta’s Instagram Platform media reference documentation as of September 2026. Platforms change these without notice.
The 300 MB cap is the one that catches people, not the duration. A 15-minute Reel exported at a typical bitrate is comfortably over 300 MB, so the two limits do not both hold at once for high quality footage. In practice, the file size is the real ceiling on a long Reel, and the fix is a lower bitrate rather than a shorter video.
The wide accepted aspect ratio range is not an invitation. Anything other than 9:16 gets letterboxed or cropped in a full-screen feed, and Meta’s own recommendation is 9:16 precisely to avoid that.
How long should a Reel actually be?
The limit and the useful length are far apart.
| Length | Best for |
|---|---|
| 3 to 15 seconds | Loops, single-idea clips, sound-led trends |
| 15 to 60 seconds | The default for most accounts: a hook, a middle, a payoff |
| 1 to 3 minutes | Tutorials and demonstrations where the steps need showing |
| 3 minutes and up | Rare. Competes directly with longer-form video elsewhere |
Instagram’s ranking leans on watch time and replays. A short Reel that loops is being counted repeatedly, and that is difficult to beat with length. If you cannot say what the viewer gets at minute four, the Reel does not need minute four.
Reels against Stories, and the other Instagram durations
| Format | Duration |
|---|---|
| Reel | 3 seconds to 15 minutes |
| Story video | 3 to 60 seconds |
| Feed video | Published as a Reel |
Instagram folded standalone feed video into Reels, which is why the Reels spec is effectively the Instagram video spec now. Story length has its own quirks, covered in Instagram Story length.
What happens when a Reel is too long or too large
Through the API, the upload fails at the container stage with an error rather than being trimmed. In the app, the editor limits the timeline. Neither one silently truncates your video, which is the useful behaviour: a Reel that publishes is a Reel that met the spec.
A scheduling tool should check the duration and the file size before queueing rather than at publish time, because a Reel that fails at 6 am is a Reel nobody sees.
The short version
- 3 seconds minimum, 15 minutes maximum, 300 MB file cap.
- The file size limit binds before the duration limit for good quality footage.
- 9:16 or expect cropping.
- Caption 2,200 characters, 30 hashtags, 20 mentions.
- For performance, 15 to 60 seconds is still the working range for most accounts.
Scheduling Reels
BulkPublish publishes Reels through Meta’s official API, so the duration and file size above are the rules that apply, and the composer checks them before a Reel is queued. Caption length is enforced at the same point. The Instagram character counter is the standalone version of that check.
If the same cut goes to TikTok and Shorts as well, posting to all three at once covers where the three specs disagree.
Where the 15 minutes came from
Instagram raised the Reels ceiling in stages, and the older figures (15 seconds, then 30, then 60, then 90 seconds, then 3 minutes) are still repeated widely because each was correct at the time. The documented figure in Meta’s current media reference is 15 minutes, and that is the number the publishing pipeline enforces today.
Anything you read that states a shorter Reels maximum as fact is describing an earlier version of the product rather than the current one. The same is true in reverse: a page quoting a longer figure has not checked either.