Characters vs. Bytes: Why Emoji and Special Characters Count Differently
A single visual character (what a person sees on screen) doesn't always correspond to a single unit in a text encoding standard — basic Latin letters typically use 1 unit, while emoji, accented characters, and many non-Latin scripts can use 2, 3, or 4 units (bytes in UTF-8, or code units in UTF-16), which is why some platforms' technical character counts differ from a simple visual count.
This distinction is genuinely technical, but understanding the basic idea explains a lot of otherwise confusing platform behavior around character limits.
Why not all characters are equal under the hood
Text is stored and transmitted digitally using an encoding standard that maps each character to one or more underlying units — common standards like UTF-8 or UTF-16 use a variable number of units per character specifically to support the enormous range of characters across world languages and symbols, including emoji.
Which characters tend to use more units
Basic Latin letters, numbers, and common punctuation typically use the fewest units. Accented Latin characters and many non-Latin scripts use somewhat more. Emoji, especially compound ones, often use the most — which is why heavy emoji use can push a text over a platform's technical limit faster than the same number of "visual characters" in plain Latin text would suggest.
Why platforms don't all handle this the same way
Different platforms were built using different underlying technologies and encoding conventions, which is part of why the same piece of text (especially one with emoji or non-Latin characters) can be measured as a different length by different platforms — there's no single universal standard every platform uses identically.