Why Character Counters Give Different Numbers

Pasted the same text into two tools and got two numbers? Here is why.

Five reasons counts differ

1. Spaces: some tools count them, some do not. Look for "with/without spaces".
2. Line breaks: Word and most tools do not count them; X and SMS do.
3. Emoji: one emoji can be up to 7 code points. Good counters show 1.
4. Full-width characters: X and Google Ads count Japanese characters as 2.
5. Bytes: an upload limit in bytes is not a character limit — Japanese takes 3 bytes per character in UTF-8.

Which number should I use?

Use the rule of the place you are posting to. Each platform page on this site counts the way that platform does.