Character Limits Explained: Twitter/X, Meta Descriptions, SMS

By Elena Marsh · August 27, 2026 · Writing

A character is not always one character. Encoding, emoji and pixel-width truncation mean the limit you are told is rarely the limit you get.

Character limits appear to be the most objective constraint in writing. In practice they are full of hidden behaviour: some systems count what you typed, others count how it is encoded, and search engines do not count characters at all.

Not every character is worth one

Text is stored as bytes, and how many bytes a character consumes depends on the encoding. Plain Latin letters take one, accented characters and most non-Latin scripts take more, and an emoji can take four or more. Worse, many modern emoji are sequences of several code points joined together, so a single visible glyph can consume a surprising amount of an allowance. A field advertising 500 characters may reject text that looks well within the limit.

SMS is the strictest case

A standard SMS holds 160 characters using a restricted seven-bit alphabet. Include a single character outside that alphabet, such as a curly quotation mark pasted from a word processor, and the whole message switches encoding and the limit drops to 70. Longer messages are split into segments and each segment carries overhead, so a 161 character message becomes two segments of 153. For anyone sending at volume, an unnoticed curly apostrophe more than doubles the bill.

Meta descriptions are measured in pixels

Search engines truncate snippets by rendered width, not character count. The familiar guidance of around 155 characters is a proxy for a pixel budget, which means a description full of wide capital letters is cut earlier than one of narrow lowercase text. The practical rule is to front-load meaning into the first hundred characters or so and treat the rest as expendable.

Writing to a limit reliably

1. Confirm what the platform counts: visible characters, code points or bytes.
2. Draft outside the input field so you keep a full version and can revise the trimmed one.
3. Put the essential message in the first half, assuming the rest may be truncated.
4. Replace curly quotes and dashes with plain equivalents for SMS.
5. Count links at their shortened length where the platform rewrites URLs.
6. Preview the result on a mobile viewport, where truncation happens earliest.

Common mistakes

• Assuming trailing whitespace is ignored; many systems count it.
• Testing a post without the link or the hashtag that will be added later.
• Writing a meta description of exactly 155 characters in wide type and losing the call to action.
• Pasting from a word processor into an SMS tool without normalising punctuation.
• Believing an emoji costs one character.

Wrapping up

Measure before you paste, put the important words first, and treat emoji and smart punctuation as expensive. That covers nearly every character limit you will meet.

Count characters, with and without spaces, in real time.

Try the Character Counter tool.

SwiftMultiTool — free online tools for everyone. Home · Blog · About · FAQ · Contact