Some wiki engines offer markup for superscript and subscript text.

==Proposed markups==

===Superscript===

%%(vertical-align: sup) Superscripted %% text

Creole: {{{ ^^This is superscripted text^^ }}}

Proposed XHTML: {{{ <sup> </sup> }}}

Comparison:
http://www.wikimatrix.org/syntax.php?i=28

===Subscript===

%%(vertical-align: sub) Subscripted text %%

Creole: {{{ ~~This is subscripted text~~ }}} or {{{ ,,This is subscripted text,, }}}

Proposed XHTML: {{{ <sub> </sub> }}}

Comparison on wikimatrix:
http://www.wikimatrix.org/syntax.php?i=29

==Rationale==

===Use cases===
* Superscript
** Basic maths
** Units of measurement (e.g. square meter - m²)
** Large numbers, metric scientific notation (e.g. 1,253x10²³)
** Ordinal numbers (e.g. 1^^st^^, 2^^nd^^, 18^^th^^ century, in French 1^^er^^, 2^^e^^, 18^^e^^ siècle)
** Possibly for footnotes (shouldn't it be handled by another mechanism than what is considered, in that particular case, as a presentation markup)

* Subscript
** Basic maths
** Basic chemistry

===Alternatives===
* Unicode digits
* Specialized markup languages like MathML, ChemML and LaTeX

===Advantages===
* Simple way to insert superscripted/subscripted text
* The users don't have to learn a new language.
* Basic functions in most word processors
* Semantic value
* Depending on the software/keyboard layout, it might be very difficult or impossible to insert Unicode superscript or subscript digits.
* Unicode digits are limited to... digits!
* Inline with [Cover the common things people need|Goals] (is it?)
* NotNew, a lot of wiki engines offer markup for superscript and subscript text. HTML offers it.
* The presentation of successive Unicode digits is not always nice (see above or this source).

===Disadvantages===
* [Better] alternatives exist
* New markups to learn, NotNew though.
* Markup characters can be hard to find on several keyboard layouts