Platform reference
Character limits and posting rules for nine social platforms
Last reviewed: 29 August 2026
The real posting constraints on X, LinkedIn, Threads, Bluesky, Instagram, TikTok, YouTube, Facebook and Pinterest: character limits, how each platform counts a character, hashtag caps and media rules. two of the nine have no single post cap at all, and this reference says which.
What is the character limit on each social platform?
The table below gives the limit Postey applies for each of the nine platforms it publishes to, the field the limit applies to, and whether the platform enforces it at publish time or only as a field maximum in its API.
| Platform | Field | Limit | Counted in | Enforced at publish? | Hashtag cap |
|---|---|---|---|---|---|
| X | post | 280 | Weighted (link 23, emoji 2) | Yes, at publish time | Not documented |
| post | 3,000 | Code points | Yes, at publish time | Not documented | |
| Threads | post | 500 | Code points | Yes, at publish time | Not documented |
| Bluesky | post | 300 | Graphemes | Yes, by the protocol | Not documented |
| caption | 2,200 | Code points | Yes, at publish time | Not documented | |
| TikTok | caption | 2,200 | Code points | Yes, at publish time | Not documented |
| YouTube | description | 5,000 | Code points | Field maximum only | 60 counted, rest ignored |
| post | 63,206 | Code points | Yes, at publish time | Not documented | |
| description | 500 | Code points | Field maximum only | Not documented |
How many social platforms does Postey publish to?
Postey publishes to nine platforms: X, LinkedIn, Threads, Bluesky, Instagram, TikTok, YouTube, Facebook and Pinterest.
Every one of the nine is a publishing target, not a roadmap entry.
Which social platform has the shortest post limit?
X has the shortest limit Postey enforces, at 280 characters per post.
Ranked by the smallest publish-time cap across the seven platforms that enforce one, checked 29 August 2026.
Facebook has the longest enforced cap, at 63,206 characters per post.
Which platforms have no single post character limit?
YouTube and Pinterest have no single post cap that Postey checks at publish time.
Each of the two publishes a per-field maximum instead, which lives in the API model rather than in a publish-time check.
Postey states the field maximum and labels it as one, because rendering a field maximum as a post cap would be a constraint nobody imposed.
Do all social platforms count characters the same way?
No. two of the nine platforms Postey publishes to count something other than plain code points.
X counts a link as 23 characters however long the link really is, and an emoji as 2. Everything else counts as one.
Bluesky counts graphemes — user-perceived characters — rather than bytes or UTF-16 code units, so a family or skin-tone emoji counts as one against the 300.
Which platforms cap the number of hashtags?
YouTube is the one platform with a documented hashtag cap in Postey’s ledger.
YouTube ignores every hashtag after the first 60. Postey counts the hashtags in a draft and flags one that goes over.
The other eight document no numeric cap, which is not the same as documenting an unlimited one, so this page states no figure for them.
What happens to a post that is longer than the platform allows?
Postey splits an over-long draft into a numbered thread on X, Threads and Bluesky. It refuses the draft on LinkedIn, Instagram, TikTok and Facebook, where the cap is enforced, and flags it with a warning on YouTube and Pinterest, where the figure is a field maximum rather than a post cap.
The splitting is Postey’s behaviour, not the platforms’ — Postey’s own backend performs no splitting and no truncation, so nothing downstream re-does it.
The six platforms that do not thread keep a long draft as one post, caption and description — refused where the cap is enforced, flagged where the figure is a field maximum.
Which platforms enforce the tightest limits?
Ranked by the smallest limit Postey checks before publishing, across the seven platforms that enforce one, checked 29 August 2026.
Where can I read the rules for one platform?
Each platform below has its own reference page stating that platform's limit, counting rule, field maxima and media rules.
- X 280 characters per post. A link always costs 23 of them and an emoji costs 2. A longer draft is split into a numbered thread rather than rejected.
- LinkedIn 3,000 characters per post. LinkedIn no longer accepts .MOV video uploads.
- Threads 500 characters per post. A longer draft is split into a numbered thread rather than rejected.
- Bluesky 300 graphemes, not bytes and not characters, enforced by the AT Protocol itself, so no upgrade raises it. A longer draft is split into a numbered thread rather than rejected.
- Instagram 2,200 characters per caption. Every carousel slide is cropped to the first slide's aspect ratio.
- TikTok 2,200 characters per caption.
- YouTube No single post cap: a title holds 100 characters and a description 5,000. That is two fields, not one limit. Every hashtag after the first 60 is ignored.
- Facebook 63,206 characters per post, but only the first 477 show before “See more”. Facebook does not thread, so a long draft stays one post.
- Pinterest No single post cap: a title holds 100 characters, a description 500 and alt text 500. That is three fields, not one limit. A carousel Pin holds at most 5 images.