What is a Hashtag?
A hashtag is a word or phrase preceded by the # symbol, such as #smallbusiness, that labels a post with a topic. It makes the post findable under that topic and helps platforms understand what it is about.
Updated · 4 min read
Why hashtags still matter
Hashtags used to be the main way to get discovered. Today recommendation systems read captions, on-screen text, audio and images to understand a post, so hashtags are a smaller signal. They still help in three ways: they tell the platform and searchers what a post is about, they let people follow or browse a topic, and branded hashtags collect user-generated content and campaign entries in one place.
Platform notes
- Instagram: since December 2025 posts and Reels are capped at five hashtags, down from the long-standing limit of 30, and Instagram says a few specific tags perform better than a long list of generic ones. Keywords in the caption now do much of the work.
- TikTok: hashtags and caption keywords help TikTok and TikTok search classify a video; a handful of specific tags is typical.
- LinkedIn: a few topical hashtags can help categorize a post, but they carry less weight than they used to.
- X: one or two hashtags on a live topic or event; more looks like spam.
- Facebook: hashtags are clickable but play a minor role in discovery.
- YouTube: hashtags in the title or description link to a hashtag page, and a few from the description can appear above the title.
How to choose hashtags
- Describe the post: what is it, and who is it for? (#veganbaking, #leedsfood)
- Add one or two community or niche tags your audience actually browses.
- Use a branded hashtag for campaigns or customer content you want to collect.
- Check each tag's recent posts: are they relevant, and is the tag free of spam?
How to measure hashtag performance
Platform insights rarely isolate hashtag reach any more, so test instead: change only the hashtags across similar posts and compare reach from non-followers. For a branded hashtag, count the posts that use it and their combined reach.
A worked example
A Leeds bakery posting a vegan brownie Reel swaps #food #yummy #instagood #love for #veganbaking #leedsfood #veganbrownies, and writes “vegan brownies in Leeds” in the caption. The tags are smaller but match what local people search for, so the post is shown to a more relevant audience.
Common mistakes
- Filling every allowed slot with generic tags such as #love or #instagood.
- Using a tag that is full of spam or restricted, which can limit a post's visibility.
- Pasting the same block of tags on every post regardless of topic.
- Launching a branded hashtag and never promoting it.
Hashtag FAQ
How many hashtags should I use?
Fewer than you might think. Instagram now allows at most five per post, and on TikTok and LinkedIn a handful of specific, relevant tags usually works better than a long list; on X, one or two. Follow each platform's current guidance, since limits change.
Do hashtags still work in 2026?
Yes, but as a supporting signal. Platforms rely more on captions, on-screen text and audio to understand posts. Use hashtags to add context and join communities, not as your main growth tactic.
Should hashtags go in the caption or the first comment?
The caption is the safer choice, since that's where platforms read a post's context. Some accounts use the first comment to keep captions tidy, but there's no clear evidence it performs better.