Hashtags still work, but not as an automatic reach lever. Their main job is to signal what a post is about and to make it appear on a topic page; how widely it is distributed depends first on the interest it generates. The rules also differ from one network to another: Instagram, for example, now limits the number of hashtags per post.

Here is what the networks' official help pages say, and a simple method for choosing your hashtags without pasting the same list everywhere.

What is a hashtag for?

A hashtag is a word or phrase preceded by the # symbol, which turns it into a clickable link. On Instagram, the official help centre explains that adding a hashtag to a post from a public account makes the post visible on the corresponding hashtag page, which gathers the photos and videos published with that same tag (Instagram Help). Posts from private accounts do not appear there publicly.

In practice, a hashtag can help you:

  • clarify the topic of a post when the text or visual leaves some doubt;
  • appear on a topic page that users browse or search;
  • group the content of a campaign, event or brand under a single tag.

On the other hand, a hashtag will not rescue content its audience is not interested in, and it does not replace a clear caption.

What changed

The major networks now recommend content based on each user's estimated interest. TikTok, for instance, explains that its For You feed ranks videos using several factors: user interactions (videos liked or shared, accounts followed, comments posted), video information, which might include captions, sounds and hashtags, and some device and account settings (TikTok Newsroom). TikTok adds that a strong indicator of interest, such as watching a longer video to the end, carries more weight than a weak indicator.

A hashtag is therefore one piece of information among others about what a post covers. It helps place the content; it does not decide on its own how far the content travels.

Instagram: five hashtags at most

Instagram's help centre states that you can use up to 5 tags on a post; if you include more, your comment won't post. Hashtags can go in the caption or in a comment. Long lists of tags under every post are therefore no longer possible.

With five slots, every tag counts: favour tags that genuinely describe the content (topic, format, place or community) over generic tags unrelated to the post.

TikTok: describe the video

On TikTok, hashtags are part of the video information the recommendation system takes into account, alongside the caption and the sound. Their role is descriptive: they say what the video is about. Choose a few precise tags on the topic and format, and take care of the caption too, since it is part of the same information.

A generic tag used on a huge number of videos, such as #fyp, says nothing about the topic of yours: it does not replace a descriptive tag.

LinkedIn: few tags, clear text

At the time of this update, we did not find a recommended number of hashtags in LinkedIn's official help. Rather than following a number, apply the same principle as elsewhere: a few tags related to the topic of the post, placed so they do not get in the way of reading. On a professional network, focus first on well-structured text and a clear idea. Our article on content formats that work on each social network covers the differences between platforms.

Pinterest: title and description first

On Pinterest, people search for Pins, save them and click on them to learn more. Pinterest's official guide to creating Pins highlights the Pin's title, board, descriptive details and link, without making hashtags a step in the process. Write a title and description that explain what the Pin shows, using the words someone would type to find it.

How to choose your hashtags: a four-step method

  • Describe the content in one sentence. Topic, format, target audience: the most useful tags come from that sentence.
  • List ideas, then sort them. To find ideas, you can start from the hashtag generator, then keep only the tags that genuinely describe your post.
  • Combine levels. One broad tag for the category, one or two precise tags for your angle and, if you have one, a brand tag to group your content.
  • Adapt to the network. Respect Instagram's limit, describe the video on TikTok, keep it light on LinkedIn and take care of the description on Pinterest.

Then adjust the selection for each post according to its actual topic, rather than pasting the same list again.

Common mistakes

  • Copying the same list under every post, whatever the topic.
  • Adding popular tags unrelated to the content to try to widen reach.
  • Going over Instagram's five-hashtag limit: the comment then cannot be posted.
  • Relying on hashtags to make up for a vague caption or a hard-to-read visual.
  • Forgetting that posts from a private account do not appear publicly on Instagram hashtag pages.

Measure the effect on your own account

Rather than relying on general averages, test on your own account. For example, post for a few weeks with your usual selection, then, over a comparable period, with a shorter and more precise selection. If the network's statistics separate reach among followers and non-followers, compare the latter above all: that is what hashtags are supposed to influence. Keep other factors as stable as possible (formats, frequency, posting times) so the comparison is meaningful.

Key takeaways

  • A hashtag signals what a post is about; it does not guarantee reach.
  • Instagram: 5 hashtags at most per post, chosen to describe the content.
  • TikTok: descriptive tags, alongside a carefully written caption.
  • LinkedIn: few tags and clear text.
  • Pinterest: a natural-language title and description.
  • One precise, relevant tag is more useful than a long generic list.

To organise your content and schedule its publication across several networks from a single interface, choosing the date, time and target networks, see HelloSocials pricing.

L'équipe Hello Socials