Testwiki:Manual of Style/Superscripts and subscripts

A superscript or subscript is text that is positioned slightly above or below the normal line of type. Superscripts and subscripts are often rendered in a smaller font size than the adjacent normal text. This part of the Manual of Style aims to achieve consistency in the use and formatting of superscripts and subscripts in Wikipedia articles.

General guidelines

Subscripts and superscripts should be wrapped in <sub> and <sup> HTML tags, respectively, with no other formatting info, with some exceptions (see below). The Template:Tlx and Template:Tlx templates are useful shortcuts to the HTML markup. Do not use the Unicode subscripts and superscripts Template:!xt and Template:!xt, or XML/HTML character entity references (Template:!xt etc.). Rather, write Template:Xt and Template:Xt to produce the superscripts Template:Xt and Template:Xt. The superscripted 2 and 3 are easier to read, especially on small displays, and ensure that exponents are properly aligned. Compare:

Template:!xt (Unicode superscripts) to

Template:Xt (w<sup>i</sup>x<sup>2</sup>z<sup>(n + 6)</sup>) or

Template:Xt (w{{sup|i}}x{{sup|2}}z{{sup|(n + 6)}})

Template:!xt (²) to

Template:Xt (<sup>2</sup>) or

Template:Xt ({{sup|2}})

These guidelines also apply in citations and template parameters; templates are responsible for cleaning up markup if needed for external consumption, e.g. for COinS.

Exceptions

Phonetic transcriptions

Phonetic transcriptions in the International Phonetic Alphabet and Uralic Phonetic Alphabet (which are most often inside Template:Tl, Template:Tl, Template:Tl, and related templates) should use Unicode subscripts and superscripts. This follows the recommendation of the International Phonetic Association and is done by the tools, help pages, and articles referenced in Wikipedia:Manual of Style/Pronunciation. Tone should usually be marked with diacritics or IPA tone symbols, according to Wikipedia:Manual of Style/Pronunciation#Tone. Use Template:Tl for any non-compliant articles.

Orthographies

Superscript and subscript symbols in orthographies of languages, such as in the Proto-Indo-European language, some Salishan languages, and the Wade–Giles romanization of Mandarin, should use Unicode subscripts and superscripts.

Titles

Another exception where Unicode superscripts and subscripts are used is in the title of articles, though this is only rarely necessary. See Template:Section link.

Short descriptions

Per WP:SDFORMAT, Template:Tl cannot use HTML or wikitext formatting, leaving Unicode characters as the only option for superscripts and subscripts.

Dates and numbers

• The ordinal suffix (e.g., th) is not superscripted (Template:Xt and Template:Xt, not Template:!xt and Template:!xt).
• Centuries and millennia are written using ordinal numbers, without superscripts and without Roman numerals: Template:Xt, Template:Xt, Template:Xt (see also Wikipedia:Manual of Style#Numbers as figures or words).
• Non-base-10 notations in non-computer-related articles use subscript notation. For example: Template:Xt, Template:Xt, Template:Xt, Template:Xt (use {{sub|radix}} or <sub>radix</sub>).

Music

• In figured bass, superscript and subscript may be combined by using math markup or by using the Template:Tlx template: <math>C_6^4</math> = $C_6^4$, ''C''{{su|b=6|p=4}} = CTemplate:Su; (see also Wikipedia:TeX markup or m:Help:Formula).
• A superscript circle, or degree sign, which indicates a diminished chord, that may not display correctly for everyone, "°", can be produced by copying and pasting, typing °, or by keying Template:Key pressTemplate:Key pressTemplate:Key pressTemplate:Key press (Windows PCs). A superscript lower case "Template:Sup" ({{sup|o}}) may be used instead. The slashed o, "Template:Sup", which may not display correctly for all readers, is produced by superscripting the character produced by typing ø, or by keying Template:Key pressTemplate:Key pressTemplate:Key pressTemplate:Key press (Windows PCs). Diminished chords can also be indicated with {{music|dim}} and {{music|dimslash}}.
• For inversions and the degree sign superscript and subscript may be done thus: vii{{sup|o}}, I{{sub|6}}. This looks like: Template:Xt, Template:Xt.

Unit symbols and abbreviations

• Powers of unit symbols such as squares and cubes are expressed with a superscript exponent (Template:Xt, Template:Xt). Use the <sup> tag or {{sup}} template rather than the Unicode superscript characters such as Template:!xt. Squared imperial and US unit abbreviations may be rendered with Template:Xt, and cubic with Template:Xt (Template:Xt, Template:Xt).

Science

Chemistry

Template:Main Descriptions of:

• Chemical compounds

Template:Xt using {{chem2|C2H5OH}}

• Isotopes

Template:Xt using Template:Tlx

Mathematics

• Exponentiation is indicated using a superscript:

Template:Xt using 2{{sup|2}} = 4

Special care is needed with subscripted labels to distinguish the purpose of the subscript (as this is a common error): variables and constants in subscripts should be italic, while textual labels should be in normal text font (Roman, upright). For example:

$x_{\text{this one}}=y_{\text{that one}}$   (correct—typeset from <math> x_\text{this one} = y_\text{that one} \,\!</math>),

and

$\sum _{i=1}^n{y}_i^2$   (correct—typeset from <math>\sum_{i=1}^n { y_i^2 }\!</math>),

but not

$r=x_{predicted}-x_{observed}$   (incorrect—typeset from r = x_{predicted} - x_{observed}).

Moreover, the TeX engine used on Wikipedia may format simple superscripts using Template:Tag depending on user preferences. Thus, instead of the image $x^2$, many users see xTemplate:Sup. Formulae formatted without using TeX should use the same syntax to maintain the same appearance.