A hashtag is a label that says what a post is about
A hashtag is like a label: a word following "#". Tap it and you see a list of posts with the same label, and search also groups them together. It has two main jobs: telling people what topic a post covers, and grouping posts on the same topic so they can be seen together. There is also a short definition in hashtag.
There was a time when people said "add lots of popular tags and you'll be found." Today, many networks cap the number of tags or treat irrelevant tags as a problem. For a business account, it is safest to think of hashtags not as something to compete on by count, but as a few labels that convey the topic correctly.
Rules by network (as of October 2026)
How hashtags are handled differs a lot between networks. Here we list only the rules each company states in its official help pages and developer documentation.
| Network | Officially stated rule |
|---|---|
| Up to 5 tags per post | |
| Threads | One topic per post, 1 to 50 characters, and "." and "&" can't be used |
| YouTube | More than 60 tags makes all tags on the video invalid. Up to 3 tags from the description appear above the title |
| X | No limit is stated, but in the published recommendation system, they don't count toward the score |
Instagram: up to 5
Instagram's help says you can use up to 5 tags per post. It used to allow up to 30, so older guides may say "add 30 tags," but that no longer matches the current rule. You don't have to use all 5 slots. Two or three tags that pin down what the post is about are enough.
Threads: one topic
On Threads you add a "topic" instead of hashtags. Meta's developer documentation states that a post can have only one topic, 1 to 50 characters long, and that "." and "&" can't be used. Since you only get one, you choose the topic closest to the post. Words that gather people with the same interest, such as an industry or a place name, work well.
YouTube: irrelevant tags can be a reason for removal
YouTube's help states that adding more than 60 hashtags to a video makes all of them invalid, and that tags unrelated to the video or misleading tags are a reason for removal. Of the tags you add to the description, up to 3 chosen by YouTube appear above the title.
X: tags don't count toward the score
X has not officially set a limit on tags, but reading the source code of the recommendation system X has published, the hashtag itself isn't part of the ranking score. What affects the score is the likelihood of reactions such as replies and link copies. The details are in what makes a post show up in X's recommendations. More tags don't raise the score and only make the text harder to read, so on X, 0 or 1 is plenty.
Facebook Pages, LinkedIn and TikTok also have hashtags, but this page includes only rules whose official numbers we could confirm.
Tags a business account should choose
Once you limit the number, which tags you choose matters. It helps to think of them in three types.
Tags that pin down the post's content
The most important is a tag that states what the post is about. Choose words your readers are likely to search for: "#croissant" for a bakery's new item, or "#bathroomrenovation" for a renovation case. Words that are too broad ("#gourmet," "#stylish") have too many posts and get buried, and they don't convey the topic anyway.
Tags for place and occasion
For shops and local companies, place-name tags work. Combining area and trade, like "#StationNameLunch" or "#CityNameBuilder," helps your posts reach people nearby. For many businesses, reaching people within a reachable area is worth more than reaching many people far away.
Tags only you have
You can also create a tag unique to your business for a campaign or series. It marks posts when customers post, and also lets you gather posts later to look back on. Before creating it, search for it to make sure it isn't used with another meaning. Cautions when featuring customers' posts are explained in handling UGC and customer posts.
Ways not to use them
Adding popular tags that don't relate
Avoid adding trending tags regardless of the content. Some networks, like YouTube, list irrelevant tags as a reason for removal, and even where they don't, people who arrive through the tag and feel "this post has nothing to do with it" will think less of your account.
Filling the body with #
If you wrap words in the text in "#" one after another, it becomes hard to read. If you add tags, group them at the end, or blend in just one naturally within the text.
Pasting the same bundle of tags every time
Pasting the same 5 or 10 tags every time makes it easy for tags that don't fit the content to slip in. Choose tags again for each post as a rule. Keep your frequently used tags as templates and pick only the ones that fit, and it saves effort.
Check how well tags work
Compare how impressions and reactions differ between posts with tags and posts without, and you'll learn what works for your account. When you compare, match the topic and time of day as much as possible and keep other differences small. The trick is not to decide from one result but to watch over several weeks. How to read the numbers is explained in the basics of social media analytics.
When you add hashtags in SNS TOWN
In SNS TOWN, the pre-publish check looks at the number of hashtags. If there are two or more, it stops the post on X accounts and shows a warning on other networks. It only warns for networks other than X because this standard was set from how X works, and some networks, like Instagram, allow up to 5. Even with a warning, you can post as is if the tags fit the content. You can see what the check covers in pre-publish check.
On Threads accounts, the composer shows a topic field separate from the body. It tells you on the spot if the topic is over 50 characters or contains "." or "&". AI drafts are also written on the assumption that hashtags, if any, number 0 or 1. If you save place-name and industry tags you use often in templates, you can insert them from the post screen.
Frequently asked questions
Should I add hashtags?
Posts reach people without them. If you add them, keep to a few that pin down the content. Instagram allows up to 5, Threads gives one topic, and on X tags don't count toward the score, so using fewer is a safe default on any network.
What about old Instagram posts that had 30 tags?
This page covers the rules for posts from now on. The current guidance is up to 5 tags per post, so choose 5 or fewer for new posts.
Is it better to use English or Japanese tags?
Choose the language your intended audience uses. Decide from the audience: tags in the local language for local customers, or one English tag mixed in if you want people overseas to see it.
I made a tag for my business but nobody uses it
A branded tag doesn't spread just because you made it. It only grows into a marker when you use it every time in a campaign or series and give customers a reason to use it. When combining it with a giveaway, also be careful about the rules on prizes.
Can't I post if I add two or more tags in SNS TOWN?
On X accounts, the post is stopped. On other networks, you only get a warning, so you can check the content and post as is.
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