Wikipedia:Manual of Style/Linking

Linking through hyperlinks is an important feature of Wikipedia. Internal links bind the project together into an interconnected whole. Interwiki links bind the project to sister projects such as Wikisource, Wiktionary, and Wikipedia in other languages, and external links bind Wikipedia to the World Wide Web.

Appropriate links provide instant pathways to locations within and outside the project that are likely to increase readers' understanding of the topic at hand. Whenever writing or editing an article, it is important to consider not only what to put in the article, but what links to include to help the reader find related information, as well as which other pages should carry links to the article. Care should be taken to avoid both underlinking and overlinking, as described below.

This page provides guidelines as to when links should and should not be used, and how to format links. Detailed information about the syntax used to create links can be found at Help:Link. The rules on linking applicable to disambiguation pages are set out in the disambiguation style guide.

Principles

Wikipedia is based on hypertext, and aims to "build the web" to enable readers to access relevant information on other pages easily. The page from which the hyperlink is activated is called the anchor; the page the link points to is called the target.

In adding or removing links, consider an article's place in the knowledge tree. Internal links can add to the cohesion and utility of Wikipedia, allowing readers to deepen their understanding of a topic by conveniently accessing other articles. Ask yourself, "How likely is it that the reader will also want to read that other article?" Consider including links where readers might want to use them; for example, in article leads, at the openings of new sections, in the cells of tables, and in image captions. But note below that as a rule of thumb editors should only link the term's first occurrence in the text of the article.

General points on linking style

  • As explained in more detail at Help:Link § Wikilinks, linking can be "direct" ([[Riverside, California]], which results in Riverside, California), or "piped" ([[Riverside, California|Riverside]], which results in Riverside in the text, but still links to the article " Riverside, California" (although Pipe trick is an easier way to create this particular link).
  • Section headings should not themselves contain links; instead, a {{ main article}} or {{ see also}} template should be placed immediately after the heading.
  • Links should not be placed in the boldface reiteration of the title in the opening sentence of a lead. [nb 1]
  • Items within quotations should not generally be linked; instead, consider placing the relevant links in the surrounding text or in the "See also" section of the article.
  • When possible, avoid placing links next to each other so that they look like a single link, as in [[Ireland|Irish]] [[Chess]] [[Championship]] ( Irish  Chess  Championship). Consider rephrasing the sentence, omitting one of the links, or using a more specific single link (e.g. to Irish Chess Championship using [[Irish Chess Championship]]) instead.
  • Articles on technical subjects might demand a higher density of links than general-interest articles, because they are likely to contain more technical terms that general dictionaries are unlikely to explain in context.
  • Beware of linking to an article without first confirming that it is helpful in context; the fact that its title matches the concept you wish to link to, does not guarantee that it deals with the desired topic at all. For example, a physicist speaking of barns is highly unlikely to wish to link to Barn instead of Barn (unit), and any reader needing to click on such a link almost certainly will struggle to make sense of what the system offers.
  • Do not create links to user, WikiProject, essay or draft pages in articles, except in articles about Wikipedia itself (see Self-references to avoid).
  • Do not unnecessarily make a reader chase links: if a highly technical term can be simply explained with very few words, do so.
  • Do use a link wherever appropriate, but as far as possible do not force a reader to use that link to understand the sentence.
  • The text needs to make sense to readers who cannot follow links. Users may print articles or read offline, and Wikipedia content may be encountered in republished form, often without links.
  • Refrain from implementing colored links that may impede user ability to distinguish links from regular text, or color links for purely aesthetic reasons.

Overlinking and underlinking

What generally should be linked

An article is said to be underlinked if words are not linked and are needed to aid understanding of the article. In general, links should be created to:

  • Relevant connections to the subject of another article that will help readers understand the article more fully (see the example below). This can include people, events, and topics that already have an article or that clearly deserve one, so long as the link is relevant to the article in question.
  • Articles with relevant information, for example: "see Fourier series for relevant background"
  • Articles explaining words of technical terms, jargon or slang expressions/phrases—but you could also provide a concise definition instead of or in addition to a link. If there is no appropriate Wikipedia article, an interwikimedia link to Wiktionary could be used.
  • Proper names that are likely to be unfamiliar to readers

Do not be afraid to create links to potential articles that do not yet exist (see § Red links below).

If you feel that a link does not belong in the body of an article, consider moving it to a "See also" section.

What generally should not be linked

An overlinked article contains an excessive number of links, making it difficult to identify links likely to aid the reader's understanding significantly. [1] A 2015 study of log data found that "in the English Wikipedia, of all the 800,000 links added ... in February 2015, the majority (66%) were not clicked even a single time in March 2015, and among the rest, most links were clicked only very rarely", and that "simply adding more links does not increase the overall number of clicks taken from a page. Instead, links compete with each other for user attention." [2]

A good question to ask yourself is whether reading the article you're about to link to would help someone understand the article you are linking from. Unless a term is particularly relevant to the context in the article, the following are not usually linked:

  • Everyday words understood by most readers in context.
  • The names of subjects with which most readers will be at least somewhat familiar – unless there is a contextually important reason to link:
    • This generally includes major examples of: geographic features (e.g., the Himalayas, Pacific Ocean, South America), locations (e.g., United States; New York City, or just New York if the city context is already clear; London, if the context rules out London, Ontario; Japan; Brazil; Southeast Asia), languages (e.g., English, Arabic, Korean, Spanish), nationalities and ethnicities (e.g., English, British, Chinese, Turkish; African-American, Hispanic), and religions (e.g., Christianity, Islam, Hinduism, Buddhism).
    • Contrasting examples: Lake Xochimilco, mid-Atlantic Ridge; Aberbeeg, Tonga; Frisian languages, Middle English; Prussian, Tohono O'odham, Afro-Cuban; Zoroastrianism, Shinreikyo
    • These are two sides of a spectrum with a grey area between them, which varies by context; exercise common sense.
  • Common occupations
  • Common units of measurement, e.g. units relating to currency, time, temperature, length, area, or volume. If both non-metric and metric equivalents are provided, as in 5 centimetres (2.0 in), usually neither unit needs to be linked, because almost all readers will understand at least one or the other unit.
  • Dates (see § Chronological items, below)

Do not link to pages that redirect back to the page the link is on (unless the link is to a redirect with possibilities that links to an appropriate section of the current article).

The function of links is to clarify, not emphasize; do not create links in order to draw attention to certain words or ideas, or as a mark of respect.

Duplicate and repeat links

Generally, a link should appear only once in an article, but if helpful for readers, a link may be repeated in infoboxes, tables, image captions, footnotes, hatnotes, and at the first occurrence after the lead. Duplicate links in an article can be identified by using a tool that can be found at User:Ucucha/duplinks. However, in glossaries, which are primarily referred to for encyclopedic entries on specific terms rather than read from top to bottom like a regular article, it is usually desirable to repeat links (including to other terms in the glossary) that were not already linked in the same entry (see Template:Glossary link).

Duplicate linking in lists is permissible if it significantly aids the reader. This is most often the case when the list is presenting information that could just as aptly be formatted in a table, and is expected to be parsed for particular bits of data, not read from top to bottom. If the list is normal article prose that happens to be formatted as a list, treat it as normal article prose.

Lead section

Too many links can make the lead hard to read. In technical articles that use uncommon terms, a higher-than-usual link density in the lead section may be necessary. In such cases, try to provide an informal explanation in the lead, avoiding using too many technical terms until later in the article—see Wikipedia:Make technical articles understandable and point 7 of Wikipedia:What Wikipedia is not § Wikipedia is not a manual, guidebook, textbook, or scientific journal.

An example article

For example, in the article on supply and demand:

  • Almost certainly link " microeconomics" and " general equilibrium theory", as these are technical terms that many readers are unlikely to understand at first sight.
  • Consider linking " price" and " goods" only if these common words have technical dimensions that are specifically relevant to the topic.
  • Do not link to the "United States", because that is an article on a very broad topic with no direct connection to supply and demand.
  • Definitely do not link "wheat", because it is a common term with no particular relationship to the article on supply and demand, beyond its arbitrary use as an example of traded goods in that article.
  • Make sure that the links are directed to the correct articles: in this example, you should link goods, not good, which goes to a page on the philosophical concept. Many common dictionary words are ambiguous terms in Wikipedia and linking to them is often unhelpful to readers; "Good" is a surname and the name of albums, companies, etc., and the article title Good (disambiguation) is used to index those.

Link clarity

The article linked to should correspond to the term showing as the link as closely as possible given the context: for example, When Mozart wrote his Requiem rather than When Mozart wrote his Requiem, or Previn conducted Mozart's Requiem rather than Previn conducted Mozart's Requiem – this makes it clear the link is to the article on Mozart's Requiem in particular, rather than that on requiems in general. The link target and the link label do not have to correspond to each other, but the link must be as intuitive as possible. Thus, one may have a piped link of " second-longest European river" with the target article Danube.

Link specificity

Always link to the article on the most specific topic appropriate to the context from which you link: it will generally contain more focused information, as well as links to more general topics.

What you type How it appears Specificity
[[Icelandic orthography]] Icelandic orthography Specific
[[Icelandic language|Icelandic]] orthography Icelandic orthography Related but less specific
Icelandic [[orthography]] Icelandic orthography Unspecific
the [[flag of Tokelau]] the flag of Tokelau Specific
the [[flag]] of [[Tokelau]] the flag of Tokelau Unspecific
[[Requiem (Mozart)|Requiem]] Requiem Specific
[[Requiem]] Requiem Unspecific

In each case the specific link is preferred.

If there is no article about the most specific topic, do one of the following things:

  • Consider creating the article yourself.
  • If an article on the specific topic does not yet exist, create a redirect page to the article about a more general topic, as described in section § Redirects. For example, if no article yet exists on the song "Sad Statue" from the album Mezmerize, create a new article called Sad Statue that is a redirect to the article Mezmerize.
  • If there is no article on a more general topic either, then create a red link, but first, read § Red links below.

When neither a redirect nor a red link appear appropriate, consider linking to a more general article instead. For example, instead of Baroque hairstyles, write Baroque hairstyles, Baroque hairstyles, Baroque hairstyles, or hairstyles of the Baroque (but not Baroque hairstyles as two adjacent links), depending on the context.

Section links

If an existing article has a section specifically about the topic, you can redirect or link directly to it, by following the article name with a number sign (#) and the name of the section. For example, underpromotion is a redirect to Promotion (chess) § Underpromotion, and in the article Quark, the link eight gluon types (typed as [[Gluon#Eight gluon colors|eight gluon types]]) links to a specific section in the article Gluon.

To link to a section within the same article, e.g. in the lead of Promotion (chess), write: [[#Promotion to rook or bishop|§ promotion to a rook or bishop]]. You can also use the {{ section link}} template for this purpose.

Broken section links

A problem can arise if the title of the section is changed for any reason, since this action will break any incoming section links (if this occurs, incoming links will default to the top of the linked article). The simplest way to prevent this breakage is to add an {{ anchor}} template just below the section title, listing the section title, and (optionally) any obsolete titles or alternative titles. This method is easy to understand, reliable, and straightforward to maintain and update. For example:
==Section name==

It is good practice to place an anchor whenever the section is expected to be the target of an incoming wikilink, either from elsewhere in the same article or from anywhere else outside the article.

An alternative, supplementary method has been to add a hidden comment to the target section such as <!-- "Quark" links here --> so that someone changing the title of that section can fix the incoming links. The hidden message (<!-- "Article" links here -->) must be added to the target section with a break between the header and the hidden message:
==Target section==
<!-- "Article" links here -->

If there is no break:
==Target section==<!-- "Article" links here -->
problems arise; for example, the target section title is not added to the edit summary when the section edit button is clicked, and the article does not return to that section after editing.

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