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Threads hashtag limit: one topic tag per post

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.

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Checked on against 7 sources.

Check a post against the one-tag rule

Type or paste. It stays in your browser.
Hashtags3 / 1
Post157 / 500
omnisocials

Planning a week of Threads posts in one sitting: a question on Monday, a photo on Wednesday, a poll on Friday. #socialmediatips #contentplanning #threadsapp

Only the first #tag becomes the post's topic. Later ones post as plain text, so they are struck through here.
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
The rules

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

Threads topic tag rules: tags per post, length, characters, multi-word tags, numbers and profile tags, October 2026
RuleLimitWhat Threads says
Tags per post1"Only one topic tag is allowed per post" (API docs)
Tag length1 to 50 charactersAPI docs
Characters not allowedPeriods and ampersandsAPI docs, for the topic_tag field
Several words or emojiYes, in the app"They can contain multiple words in a single tag" (Threads for Creators)
A #tag written in the textEnds at a space or punctuationAPI docs; so a tag in the text is one word
Numbers"#1" is not a tagAPI docs, since October 2024
Profile tagsNo number publishedAdded in March 2025
App vs schedulers

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

How a Threads topic tag is added in the app, through the API's topic_tag field, through a #tag in the text, and in OmniSocials
MethodHow it worksNotes
Threads appAdd the tag in the composerSeveral words and emoji allowed; Threads suggests tags as you write
API, topic_tag fieldA separate field, since July 20251 to 50 characters, no periods or ampersands
API, #tag in the textThe first valid #tag becomes the topicMeta keeps it for backward compatibility; one word only
OmniSocialsWrite the #tag in your postThe 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.
What changed

How tags changed on Threads. Still one per post.

  1. 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. Source

  2. 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). Source

  3. 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. Source

Tips

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.

Other platforms

The same guide for every network. Each one has its own rules.

Sources

How we built this guide. Checked on October 17, 2026.

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.

  1. Meta for Developers: Threads posts (topic tags)Read Oct 2026One topic tag per post, 1 to 50 characters; the first valid #tag in the text is used.
  2. Instagram for Creators: Threads for creatorsRead Oct 2026Tags can hold several words and emoji, and help reach people interested in the topic.
  3. Meta for Developers: Threads publishing referenceRead Oct 2026The topic_tag field and the characters it cannot hold.
  4. Meta for Developers: Threads API changelogRead Oct 2026
  5. Social Samosa: Meta introduces topic tags, reply controls and video updates on ThreadsMar 21, 2025
  6. Social Media Today: Threads rolls out topic tags to all users globallyDec 7, 2023One tag per post, added by hand in the composer.
  7. Buffer Help Center: Character limits for each social networkRead Oct 2026Threads: 500 for posts and 50 for topics.
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