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Social media video specs for TikTok, Instagram and YouTube
Format, orientation and media
What each target accepts, and what it does with a cover image.
| Target | Video orientation | Static images | Custom cover | Title |
|---|---|---|---|---|
| TikTok | Portrait or square (9:16 is the norm) | Yes — photo post, up to 35 slides | No — TikTok picks a frame from the video | Photo posts only, cut to 90 characters |
| Instagram Reels | Portrait or square (9:16) | No — images go to the Instagram Post target | Yes — a custom cover image | Not used |
| Instagram Post | Image target — no video | Yes — one photo or a carousel up to 10 slides | No — the first image is the cover | Not used |
| YouTube Shorts | Portrait or square (9:16) | No — YouTube takes videos only | No — the thumbnail comes from the video | Required, max 100 characters |
| YouTube long-form | Landscape (16:9) | No — YouTube takes videos only | Yes — set at publish time | Required, max 100 characters |
9:16 and 16:9 are the shapes these targets are built around, but the app classifies on orientation alone: height greater than or equal to width is shortform, wider than tall is long-form. A 4:5 video is still routed to the vertical targets.
Caption, description and title limits
The hard character limits. Going over is a publish failure, not a truncation — nothing here silently cuts your text.
| Target | Field | Max characters | What counts toward it |
|---|---|---|---|
| TikTok | Caption | 2,200 | Caption plus every hashtag, joined into one string |
| Instagram Reels | Caption | 2,200 | Caption plus every hashtag |
| Instagram Post | Caption | 2,200 | Caption plus every hashtag (one caption for the whole carousel) |
| YouTube Shorts | Description | 5,000 | Caption, hashtags, and the #Shorts tag added automatically |
| YouTube long-form | Description | 5,000 | Caption plus every hashtag |
- YouTube titles are capped at 100 characters and are required on both YouTube targets. A content title can be up to 200 characters inside the app, so a long working title has to be shortened before it can go to YouTube.
- YouTube also rejects
<and>anywhere in the title or description. - Up to 50 hashtags per target, each up to 100 characters. They are appended to the caption before the length check, so they eat into the same budget.
- Shorts get
#Shortsappended automatically when the caption and hashtags don't already contain it — worth remembering if you are close to the ceiling.
Paste a caption into the caption length checker to see it counted against all five limits at once.
Files, slides and upload rules
The mechanical constraints — the ones that surface as a failed upload rather than a rejected caption.
512 MB per file into the app
That's ContentWorkflow's own cap on a single upload, video or image. Captured poster frames are held to 2 MB. Each platform applies its own limits on top of that.
Slide counts
An Instagram carousel takes up to 10 images — the API's limit. A TikTok photo post takes up to 35. Extra images attached to the content are left out of the post rather than failing it.
How the bytes get there
TikTok and YouTube receive the file directly — TikTok in one chunk up to 64 MB, otherwise in 10 MB chunks; YouTube over a resumable upload. Instagram is the odd one out: Meta fetches the file from a signed URL itself.
Resolution and duration
The app records the pixel dimensions it measures at upload and uses them only to decide orientation — it doesn't enforce a resolution and it doesn't re-encode anything. It enforces no duration limit either; for TikTok it reads the maximum that specific account allows live from TikTok at post time.
Instagram publishing needs a Professional (Business or Creator) account, and when Meta refuses the media the app's own hint is to check the format: MP4 or MOV at 9:16 for Reels, JPEG or PNG for photos. Both Instagram and TikTok are given four minutes to finish processing before the run is treated as stalled.
How these limits behave inside ContentWorkflow
A spec sheet is only useful if something checks it for you.
Orientation decides the targets
On upload the app measures the file. Taller than wide — or square — reads as shortform and pre-ticks TikTok, Reels and Shorts. Wider than tall reads as long-form. Images pre-tick Instagram Post and TikTok.
Captions are checked before upload
Caption and hashtags are joined, then measured against the target's limit. Over the limit fails immediately with the number rather than burning an upload and failing at the platform.
Each target keeps its own text
Write once at the content level and every platform inherits it. Override the caption on one row and only that row changes — useful when one platform's limit is the binding one.
The same video, its cuts, its captions and its five publish targets live on one screen. See everything else in the app or the publishing side in detail.
How current is this?
The honest caveat that belongs on every specs page.
Everything above reflects what ContentWorkflow enforces today, taken from the code that runs the publish. It is not a copy of each platform's full developer documentation, and it deliberately leaves out numbers the app doesn't check — there's no bitrate table here, because nothing in the app would enforce one.
Platforms move the goalposts. Caption ceilings, carousel sizes and accepted formats all change without much notice, and when they do, this page is updated after the app is. If a platform has just changed something and a publish fails with a limit that doesn't match what you read here, the platform's error is the one to trust.
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