Twitter increased its post limit from 140 to 280 characters in 2017.
The change was announced in September 2017 and rolled out more broadly later that year. Twitter said the experiment was designed to give users more room to express themselves, especially in languages where characters often carry less information per symbol.
Before the change, tweets were limited to 140 characters, a constraint inherited from the length of SMS messages. Twitter’s developers originally designed the service around mobile-phone texting, which helped make the short format central to its identity.
The 280-character limit did not apply identically to every element of a post. Media attachments, links and some other features were handled separately from the text count. The limit also applied to posts after the company rebranded as X in 2023, although later premium features introduced longer posting options.