Editing UTF-8 (section)

== Comparison to UTF-16 ==
{{See also|Comparison of Unicode encodings}}
{{unsourced section|find=UTF-8|find2=comparison to UTF-16|date=December 2024}}

For a long time there was considerable argument as to whether it was better to process text in [[UTF-16]] or in UTF-8.

The primary advantage of UTF-16 is that the [[Unicode in Microsoft Windows|Windows API]] required it for access to all Unicode characters (UTF-8 was not fully supported in Windows until May 2019). This caused several libraries such as [[Qt (software)|Qt]] to also use UTF-16 strings which propagates this requirement to non-Windows platforms.

In the early days of Unicode there were no characters greater than {{tt|U+FFFF}} and [[combining characters]] were rarely used, so the 16-bit encoding was effectively fixed-size. Some believed fixed-size encoding could make processing more efficient, but any such advantages were lost as soon as UTF-16 became variable width as well.

The code points {{tt|U+0800}}{{ndash}}{{tt|U+FFFF}} take 3 bytes in UTF-8 but only 2 in UTF-16. This led to the idea that text in Chinese and other languages would take more space in UTF-8. However, text is only larger if there are more of these code points than 1-byte ASCII code points, and this rarely happens in the real-world documents due to spaces, newlines, digits, punctuation, English words, and (depending on document format) markup.

UTF-8 has the advantages of being trivial to retrofit to any system that could handle an [[extended ASCII]], not having byte-order problems, and taking about half the space for any language using mostly Latin letters.