Against platform limits
Last updated 28 August 2026
The rules hashtags actually follow
A hashtag runs from the hash until the first character that is not a letter, number or underscore. That single rule explains most of the confusion around them: a space ends it, a hyphen ends it, an apostrophe ends it, so #best-of-2026 posts as #best and the rest becomes plain text. Numbers are allowed but a tag made only of numbers usually is not. Case is ignored for matching — #OOTD and #ootd reach the same feed — but capitalisation is still worth using for readability, since #ShareYourStory is far easier to parse at a glance than #shareyourstory, and screen readers handle it better too. Duplicates do nothing except use up your limit, which is why removing them is usually the single most useful cleanup on a caption someone has been adding to over time.
Common questions
Do capital letters matter in a hashtag?
Not for matching — #OOTD and #ootd go to the same place. They matter for readability: #ShareYourStory is easier to read than #shareyourstory, and screen readers pronounce the capitalised version as separate words rather than one run-on string.
Why did my hashtag get cut short?
A hashtag ends at the first character that is not a letter, number or underscore. Hyphens, apostrophes, spaces and punctuation all terminate it, so #best-of becomes #best with the rest as plain text.
What are the platform limits?
Instagram allows thirty per post, X counts hashtags against the character limit rather than capping them, TikTok is bounded by its caption length, and LinkedIn has no hard cap though three to five is the usual advice. All of these are checked as you type.
Do duplicate hashtags help reach?
No. A repeated tag is counted once by the platform and simply consumes one of your allowed slots, which is why deduplicating is worth doing on any caption that has been edited over time.