# Threads hashtag limit: one topic tag per post

> Threads uses one topic tag per post, not hashtags. Tags take 1 to 50 characters. Through schedulers, only the first #tag in your text becomes the topic.

Page: https://omnisocials.com/threads-hashtag-limits
Checked: October 17, 2026

Threads has no hashtags in the Instagram sense. Each post takes one topic tag, which helps people find it. Paste a post below: the first #tag becomes the topic, and every later one is struck through because it stays plain text.

## The short answer: One topic tag per post. Extra #tags stay plain text.

Threads uses topic tags instead of hashtags. Meta's API docs say "Only one topic tag is allowed per post", and a tag can be 1 to 50 characters. In the app you add the tag in the composer, and it can hold several words and emoji.

Tags do help. Threads says relevant topic tags "help you reach more people who are interested in that topic specifically". Through the API, as schedulers post, the first #tag in the text becomes the topic, so put the one that matters first.

- **Tags per post**: 1 (A topic tag, not a hashtag)
- **Tag length**: 50 (Characters at most, 1 at least)
- **Extra #tags**: Plain text (Only the first one counts)

## Check a post against the one-tag rule

- Post: up to 500 characters.
- Hashtags: up to 1 per post.

## How the one tag works. In the app and through the API.

| Rule | Limit | What Threads says |
|---|---|---|
| Tags per post | 1 | "Only one topic tag is allowed per post" (API docs) |
| Tag length | 1 to 50 characters | API docs |
| Characters not allowed | Periods and ampersands | API docs, for the topic_tag field |
| Several words or emoji | Yes, in the app | "They can contain multiple words in a single tag" (Threads for Creators) |
| A #tag written in the text | Ends at a space or punctuation | API docs; so a tag in the text is one word |
| Numbers | "#1" is not a tag | API docs, since October 2024 |
| Profile tags | No number published | Added in March 2025 |

## Three ways to add the tag. And which one OmniSocials uses.

| Method | How it works | Notes |
|---|---|---|
| Threads app | Add the tag in the composer | Several words and emoji allowed; Threads suggests tags as you write |
| API, topic_tag field | A separate field, since July 2025 | 1 to 50 characters, no periods or ampersands |
| API, #tag in the text | The first valid #tag becomes the topic | Meta keeps it for backward compatibility; one word only |
| OmniSocials | Write the #tag in your post | The first #tag becomes the topic, and the preview marks it |

Checked on October 17, 2026 against Meta's Threads API docs and Threads for Creators. OmniSocials does not use the separate topic_tag field yet.

## How tags changed on Threads. Still one per post.

- **Jul 2025: A topic tag field in the API** Schedulers can now send the tag as its own field instead of a #tag in the text. Tag search arrived in the API at the same time. (https://developers.facebook.com/docs/threads/changelog)
- **Mar 2025: Tags on profiles, suggestions in the composer** Profiles can show topic tags below the bio, and Threads suggests tags while you write. Meta said tagged posts get more visibility (reported by Social Samosa). (https://www.socialsamosa.com/news-2/meta-introduces-topic-tags-reply-controls-video-updates-threads-8875520)
- **Oct 2024: "#1" is no longer a tag** Through the API, a hash sign followed by a number stopped turning into a tag, and the list of characters a tag cannot hold was updated. (https://developers.facebook.com/docs/threads/changelog)

## Pick your one tag well. One chance per post.

1. **Pick one specific tag** Only one counts, so choose the community you want to reach, not the broadest word.
2. **Put it first when you schedule** Through the API the first #tag in the text becomes the topic. Any later #tags stay plain text.
3. **Skip the hashtag block** A row of #tags adds clutter and no reach on Threads. One tag and clear words do the work.
4. **Use words people search** Threads says people find tagged posts by tapping the same tag or using keyword search. Name the topic in plain words too.
5. **Keep it short and clean** Tags take up to 50 characters. Through the API, periods and ampersands are not allowed.
6. **Add tags to your profile** Since March 2025 you can show topic tags on your profile, so people see what you post about.

## Schedule it with OmniSocials

Write your tag in the post, and OmniSocials shows which one Threads will use as the topic. OmniSocials schedules posts to Threads and 11 more networks from one calendar, and AI agents (Claude, ChatGPT and others) can plan and schedule through its MCP server. $10 per seat a month billed yearly, $12 monthly; 14-day free trial, a card is needed to start it. https://omnisocials.com/pricing

## Sources and method

The rules come from Meta's Threads API documentation and Threads for Creators, read on October 17, 2026. Threads has no hashtag limit in the Instagram sense: it has one topic tag per post, and the page counts that tag. Where Threads publishes no number, such as tags on a profile, the page says so.

- Meta for Developers, [Threads posts (topic tags)](https://developers.facebook.com/docs/threads/posts), Read Oct 2026. One topic tag per post, 1 to 50 characters; the first valid #tag in the text is used.
- Instagram for Creators, [Threads for creators](https://creators.instagram.com/threads), Read Oct 2026. Tags can hold several words and emoji, and help reach people interested in the topic.
- Meta for Developers, [Threads publishing reference](https://developers.facebook.com/docs/threads/reference/publishing), Read Oct 2026. The topic_tag field and the characters it cannot hold.
- Meta for Developers, [Threads API changelog](https://developers.facebook.com/docs/threads/changelog), Read Oct 2026
- Social Samosa, [Meta introduces topic tags, reply controls and video updates on Threads](https://www.socialsamosa.com/news-2/meta-introduces-topic-tags-reply-controls-video-updates-threads-8875520), Mar 21, 2025
- Social Media Today, [Threads rolls out topic tags to all users globally](https://www.socialmediatoday.com/news/threads-rolls-out-topic-tags-to-all-users-globally/701915/), Dec 7, 2023. One tag per post, added by hand in the composer.
- Buffer Help Center, [Character limits for each social network](https://support.buffer.com/articles/character-limits-for-each-social-network-mNDqsEV9Nf), Read Oct 2026. Threads: 500 for posts and 50 for topics.

## Related guides

- [Best time to post on Threads](https://omnisocials.com/best-time-to-post-on-threads)
- [How often to post on Threads](https://omnisocials.com/how-often-to-post-on-threads)
- [Threads image sizes](https://omnisocials.com/threads-image-sizes)
- [Threads character limits](https://omnisocials.com/threads-character-limits)
- [Threads video lengths](https://omnisocials.com/threads-video-lengths)
- [Schedule Threads posts](https://omnisocials.com/threads)
- [Connect Threads](https://omnisocials.com/help-center/integrations/threads)
- [Create a post](https://omnisocials.com/help-center/creating-content/create-post)
- [MCP server](https://omnisocials.com/mcp)
- [REST API](https://omnisocials.com/api)
- [API reference](https://docs.omnisocials.com)

## FAQ

### Do hashtags work on Threads?

Not like on Instagram. Threads uses one topic tag per post, and Threads says a relevant tag helps you reach people interested in that topic. Any extra #words stay plain text.

### How many hashtags can you use on Threads?

One topic tag per post. Meta's docs: "Only one topic tag is allowed per post."

### What happens if I add more than one #tag?

Through the API, the first valid #tag in the text becomes the topic and the rest post as plain text. In the app you add one tag in the composer.

### How do I add a topic tag on Threads?

In the app, add it while you write the post; Threads also suggests tags. If you schedule, write the #tag in your text, or a tool can send it in the API's topic_tag field.

### Can a Threads tag have spaces?

In the app, yes: Threads says a tag can hold several words and emoji. A #tag written in the text through the API ends at the first space, so it is one word.

### How long can a Threads topic tag be?

1 to 50 characters. Through the API, periods and ampersands are not allowed.

### Does the topic tag count toward the 500 characters?

A #tag written in the text counts like any other text. The API's separate topic_tag field is not part of the post text.

### Can I add tags to my Threads profile?

Yes. Since March 2025 profiles can show topic tags below the bio. Threads publishes no maximum.

### Why doesn't "#1" turn into a tag?

Through the API, since October 2024, a hash sign followed by only a number is not converted into a tag. Use a word instead.

### Can OmniSocials add a Threads topic tag?

Yes, through your text: the first #tag in the post becomes the topic, and the preview marks which one. Hashtag sets work too, but only their first tag becomes the topic.