String length is not one number. Platforms care about characters with spaces, characters without spaces, words, sentences, or encoded bytes. Unicode and emoji make “how long is this?” depend on whether you count code points, grapheme clusters, or UTF-8 size on the wire.
This guide separates those metrics, shows how limits differ across social, SMS, and SEO fields, and gives a practical counting workflow. Paste any draft into the free string length checker for live character, word, and byte tallies in the browser.
For reading-time and readability-focused tallies, use the word count checker and word count guide. For dummy copy at a target length, try the lorem ipsum generator.