A 12MB PNG for an Instagram post
Instagram’s publishing API accepts JPEG images up to 8MB; a 12MB PNG would need to be compressed and converted before it can be scheduled.
Instagram Reel video specs and media spec checker
Instagram Reel video specs: MP4 or MOV, up to 1 GB, 3 seconds to 15 minutes long, ideally vertical 9:16. Below are the accepted formats, file-size ceilings and video lengths for images, video and GIFs on every network SkedCast publishes to: the same specs its composer checks before a post can be scheduled, taken from each platform’s publishing API.
What are the Instagram Reel video specs?
Instagram publishes every single video as a Reel, so these are the limits for any video post:
| Spec | Limit |
|---|---|
| Format | MP4 or MOV |
| File size | Up to 1 GB |
| Length | 3 s to 15 min |
| Shape | 9:16 (vertical, full screen) |
Check a clip’s length against every network with the Reel length checker.
What image formats and sizes does each platform accept?
| Platform | Formats | Max size |
|---|---|---|
| X (Twitter) | JPEG, PNG, WEBP, GIF | 5 MB |
| JPEG, PNG, GIF | 5 MB | |
| JPEG | 8 MB | |
| Facebook Pages | JPEG, PNG | 10 MB |
| TikTok | JPEG, WEBP, PNG | No stated limit |
| YouTube | Not supported | — |
| Threads | JPEG, PNG | 8 MB |
| JPEG, PNG | 20 MB | |
| Bluesky | JPEG, PNG, WEBP | 1 MB |
| Telegram | JPEG, PNG | 10 MB |
| Google Business Profile | JPEG, PNG | 5 MB |
What video formats, sizes and lengths does each platform accept?
| Platform | Formats | Max size | Max length |
|---|---|---|---|
| X (Twitter) | MP4, MOV | 512 MB | 140 s |
| MP4, MOV, WEBM | 5 GB | 30 min | |
| MP4, MOV | 1 GB | 15 min | |
| Facebook Pages | MP4, MOV | 10 GB | 4 h |
| TikTok | MP4, MOV, WEBM | 4 GB | 10 min |
| YouTube | MP4, MOV, WEBM, AVI | 256 GB | 12 h |
| Threads | MP4, MOV | 1 GB | 5 min |
| MP4, MOV, M4V | 2 GB | 15 min | |
| Bluesky | MP4, MPEG, WEBM, MOV | 300 MB | 3 min |
| Telegram | MP4 | 50 MB | 5 min |
| Google Business Profile | Not supported | — | — |
Which platforms accept GIFs, and how large?
| Platform | Formats | Max size |
|---|---|---|
| X (Twitter) | GIF | 15 MB |
| GIF | 5 MB | |
| Not supported | — | |
| Facebook Pages | GIF | 30 MB |
| TikTok | Not supported | — |
| YouTube | Not supported | — |
| Threads | GIF | 8 MB |
| GIF | 20 MB | |
| Bluesky | GIF | 1 MB |
| Telegram | GIF, MP4 | 50 MB |
| Google Business Profile | Not supported | — |
How to check Instagram Reel video specs and other platforms
- Find your platform and media kind. Look up the row for the exact platform and whether you are attaching an image, a video or a GIF, since each has its own spec.
- Check the format first. Confirm your file is in an accepted format for that platform and media kind — an unsupported format fails before size or duration is even checked.
- Check the file size against the ceiling. Compress or re-export before scheduling if your file exceeds that platform’s maximum, since most publishing APIs reject an oversized file outright.
- Check duration for video. Trim any video that exceeds the platform’s maximum duration, and remember Reels/Shorts formats often have a separate, shorter limit than a standard feed video.
- Treat these as API limits, not always in-app limits. A platform’s own app sometimes accepts a slightly different format or size than its publishing API — these specs describe what a scheduler can actually publish.
What does it look like in practice?
A 600MB video for X
X’s video upload allows files up to 512MB; a 600MB export needs re-compressing to fit, independent of whether its 140-second duration is already within limits.
A WebM video for TikTok
TikTok accepts MP4, MOV and WebM video files up to 4,096MB and 600 seconds, so a WebM export is fine as long as it clears the size and duration ceilings.
What do you do when a file fails the spec?
Fix the one thing that fails: convert the format, shrink the file with the image compressor, resize it with the image resizer, or trim the video. SkedCast’s composer runs these same checks as you attach a file, so a post that does not fit a network is flagged before it is scheduled, not after it fails.
Media spec FAQ
- What image formats does each platform accept?
- Most platforms accept JPEG and PNG; Instagram’s publishing API is JPEG-only (PNG and WebP get converted), and TikTok’s photo posts additionally accept WebP.
- What is the largest video file size a platform will accept?
- It varies widely — X caps video at 512MB, TikTok at 4,096MB, Facebook feed video at 10,240MB, and YouTube at 262,144MB, reflecting how differently each platform is built for video.
- Do GIFs work the same as videos?
- No. A GIF has its own, smaller limits, closer to an image than a video, and Instagram, TikTok, YouTube and Google Business Profile take no GIFs at all; convert a GIF to a short MP4 for those.
- Why would a file fail even though it looks fine in the app?
- Because a platform’s own app and its publishing API do not always share identical limits — the API a scheduler uses can be stricter, or occasionally more permissive, than what you can upload by hand in the app.
- Does every platform support video?
- The ten social networks in this table all take video in some form (SkedCast posts only photos to Google Business Profile), but the duration and file-size ceilings differ enormously — from X’s 140 seconds to YouTube’s 12-hour maximum.
- What happens if a file exceeds the spec?
- Most publishing APIs reject an out-of-spec file outright with an error, rather than resizing, trimming or compressing it automatically — the file has to be fixed before it will schedule.
- Are these specs the same everywhere the platform is used?
- These reflect each platform’s own publishing API as documented today; a platform can and does change its specs, so a rejected file is also worth checking against that platform’s current developer documentation.
- Are Instagram Reel video specs the same as the regular Instagram video row?
- Yes. Instagram publishes every single video as a Reel, so the Instagram video row is the Reel spec: MP4 or MOV, up to 1 GB, 3 seconds to 15 minutes, ideally 9:16.
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