Threads' limits are short and mostly sensible, with one trap in the text count and one in links.
Text: 500 bytes
The limit is 500 characters counted as UTF-8 bytes. Unaccented Latin letters cost one byte, accented letters two, most emoji four, and some emoji with skin tones or joined sequences eleven or more. A post of 490 visible characters with three emoji is 502 bytes and the API refuses it; most character counters say 490.
Text is optional when the post has a picture or video.
Links: five
A post with more than five links is refused by the API (a rule from late 2025). Links in the text are counted by Threads, not just the one attached as a link preview.
Media
| Rule | |
|---|---|
| Pictures per post | 20, as a carousel |
| Picture format | JPEG or PNG |
| Picture size | 8 MB |
| Picture ratio | up to 10:1 |
| Picture width | 320 to 1,440; Threads resizes outside this |
| Video | 1 per post or in a carousel; MP4 or MOV; up to 1 GB and 5 minutes; 23 to 60 fps |
| Alt text | Per item |
Other parts of a post
| Polls | Up to 4 options, on text posts |
| Reply control | Everyone, accounts you follow, mentioned only, or the parent author only |
| Topic | One topic tag |
| Threads (chains) | Replies posted in order under the first |
| Quote | Through the API |
| Editing | Not possible; delete and re-post |
| Location | Through the API |
Publishing
Two steps: create a container, wait for Threads to process it (video takes longer), publish. A tool that does not wait publishes nothing and reports success. Threads limits an account to 250 API posts in 24 hours and 1,000 replies.
How schedulers count, and why it matters
Most composers show one counter for every network, counting characters. On Threads that counter is right for a post in plain English and wrong for everything else. A caption written in Czech, Polish, German or Spanish with accents runs about 10 percent over what the counter says; a caption with a row of emoji runs far over. The failure arrives from the API at publish time as a generic "invalid parameter", with no mention of length.
The same caption often also goes to Instagram, where the limit is 2,200 characters, and to Bluesky, where it is 300 graphemes. A post that is fine on Instagram and over on Threads is the usual case, which is why a per-network count beside the box matters more on Threads than anywhere else: the Threads version is usually a trimmed copy of the Instagram one, and the trim has to be measured in bytes.
Writing for Threads from a scheduler
In Preflight, Threads is one target among the rest. The counter under the box shows bytes for Threads while it shows characters for Instagram and graphemes for Bluesky, and a "different text for Threads" variant can be shorter than the Instagram caption without retyping the rest. The Threads settings card holds reply control, the topic and poll options; a chain is written as a thread, one part per box, each part counted on its own. Pictures outside JPEG and PNG, over 8 MB or past 10:1 are refused before upload, and a video over five minutes or outside 23 to 60 fps is refused with the figure.
After publishing, the post's views, likes, replies, reposts and quotes are read back and shown with the post, and replies can be answered or hidden from the comments inbox.
Figures and comments
Views, likes, replies, reposts and quotes per post; follower count daily. Replies can be read, answered and hidden through the API.
What Preflight checks before upload
Bytes rather than characters, five links, picture format, size and ratio, the width warning, video length, size and frame rate, the 20-item carousel, the poll's options, and that a container is ready before publishing.
Rules from the Threads API documentation, checked 5 October 2026. All networks: the limits page.
Questions people ask
- How many characters can a Threads post have?
- 500 bytes of UTF-8. That is 500 plain letters, fewer with accents, and far fewer with emoji, which cost four bytes each.
- How many pictures can a Threads post have?
- Up to 20 in a carousel, JPEG or PNG, 8 MB each, with a ratio of at most 10:1.
- Can Threads posts be edited?
- Not through the API. Delete and post again.