Type once, see what fits everywhere. Live limits for X, Threads, Instagram, TikTok, LinkedIn, Facebook and YouTube Shorts. Free, no signup, nothing leaves your browser.
Writing one caption for 8 platforms by hand gets old. Smart Post Studio's AI Writing Studio drafts platform-aware captions (Instagram length ≠ X length) and schedules everywhere from your desktop — free plan, no card.
Try the free planType or paste your Instagram post into the text box above and the character count, word count and line count update as you go, including spaces and line breaks. The Instagram caption character limit is 2,200 characters (with up to 30 hashtags). The Instagram bio character limit is 150 characters. The Instagram username character limit is 30 characters — letters, numbers, periods and underscores only. The same counter works for every other platform's post limit, and the "characters remaining" figure is the one to watch: it tells you how much room is left before the platform cuts you off, not just the total number of characters. It's a character counter, not a word counter — if you need words, divide by roughly five.
Notes on how platforms count. Limits above are the published caps as of September 2026. X counts every URL as 23 characters regardless of its real length, and paid X tiers allow up to 25,000 characters. Threads allows a separate 10,000-character text attachment beyond the 500-character post. Instagram shows roughly the first 125 caption characters before "…more"; TikTok truncates around 100–150 characters in the feed. This counter uses Unicode code points, which can differ by a character or two from a platform's own counter on emoji-heavy text. Fanvue has no publicly documented caption limit, so it isn't scored here.
More free tools: smartpoststudio.com/tools