Character Limits Explained: Twitter, LinkedIn, SMS & Beyond
Platform limits aren't arbitrary — they shape how ideas travel. Know the numbers and write for the medium.
Every platform has a character limit, and every character limit has a history. Understanding why limits exist — and what they encourage — makes you a better writer on every platform.
Twitter/X: 280 characters
Twitter started at 140 characters because SMS messages were limited to 160 characters, and Twitter needed room for the username. It doubled to 280 in 2017. Despite the expansion, the best tweets are often still under 140 characters. The constraint rewards directness, punishes hedging, and forces the writer to commit to a single idea.
SMS: 160 characters
The 160-character limit for SMS was set in 1985 by Friedhelm Hillebrand, who typed sentences on a typewriter and found that most could be expressed in under 160 characters. Modern phones concatenate long SMS messages automatically, but marketers still write to 160 to avoid message fragmentation and extra carrier charges.
LinkedIn: 3,000 characters for posts
LinkedIn allows up to 3,000 characters for posts, but most engagement happens in the first 210 characters — what's visible before the "see more" cutoff. Front-load your most interesting idea. Write the first line as if it has to earn the click to expand.
Instagram: 2,200 characters for captions
Instagram caps captions at 2,200 characters, but only the first 125 characters show without tapping "more." Long captions work when you have a genuinely engaged audience and something worth saying. For most posts, 125 characters of punchy copy outperforms 2,000 characters of explanation.
Meta descriptions: 155–160 characters
Google truncates meta descriptions around 155–160 characters in search results. Writing within this limit ensures your summary isn't cut off mid-sentence. Every character counts — this is the one paragraph that determines whether someone clicks your link.