How long should captions be on each platform?
The short version
- The shortest common limit is on X (280 weighted characters) and Bluesky (300). If one caption has to work in both places, write to that limit first.
- Most channels allow far more than people read. What matters is the text visible before the see-more cut-off, which is much shorter than the limit.
- Hashtag rules differ: some channels cap them, some ignore all of them past a cap, and some use a single topic tag.
Caption limits by platform
| Platform | Text limit | Hashtag cap | Roughly visible before see more | Confidence | Notes |
|---|---|---|---|---|---|
| 2,200 characters | 30 | About 125 characters | Stated by the platform | Caption up to 2,200 characters and up to 30 hashtags. | |
| 63,206 characters | No documented cap | About 477 characters | Approximate | Very long posts are allowed; only the first lines show before 'See more'. | |
| X | 280 weighted characters | No documented cap | Not applicable | Stated by the platform | 280 weighted characters for standard accounts: every link counts as 23, CJK characters and emoji count as 2. Longer posts need a premium account. |
| 3,000 characters | No documented cap | About 210 characters | Stated by the platform | Posts up to 3,000 characters; roughly the first 210 show before 'see more'. | |
| TikTok | 2,200 characters | No documented cap | About 100 characters | Approximate | Checked against 2,200, the conservative value; some regions allow more. |
| YouTube | 5,000 characters | 15 | About 100 characters | Stated by the platform | Description up to 5,000 characters, title up to 100. If a video has more than 15 hashtags YouTube ignores all of them. |
| 500 characters | 20 | About 50 characters | Approximate | Pin title up to 100, description up to 500 characters. | |
| Threads | 500 characters | 1 | Not applicable | Approximate | Posts up to 500 characters; Threads uses a single topic tag per post. |
| Bluesky | 300 characters | No documented cap | Not applicable | Stated by the platform | 300 graphemes per post. |
Stated by the platform means the value appeared in that platform's own documentation when we last read it; we have not re-checked each live help page since. Approximate means it is commonly reported or changing, so we check against the conservative value.
Using the numbers
- Put the point of the post first. The visible prefix is the only part many people see.
- Count the way the platform counts. X counts links as a fixed length and some characters, such as emoji, as two.
- Do not stuff hashtags. A hashtag cap is a ceiling, and the recommended number is much lower than the cap.
- Check a real caption against these limits with the free caption check.
Sources and how to verify
Only the source above is cited directly. For every other platform, open its own help or developer documentation and confirm the current value. We list a review date and a confidence level instead of presenting these limits as permanent.