Wikipedia:Manual of Style/Linking

For technical information about link formatting, see Help:Link.

"Wikilinks" redirects here. For the IRC script, see WP:Scripts/Wikilinks.

Linking is one of the most important features of Wikipedia. Linking through hyperlinks is an important advantage of an online encyclopedia, with internal links binding the project together into an interconnected whole. External links, on the other hand, help link Wikipedia into the external World Wide Web, and interwiki links link the project to other sister projects such as Wiktionary.

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

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

Principles

Wikipedia is based on hypertext, and aims to "build the web" to enable readers to find relevant information on other pages with just a click of the mouse. Therefore in adding or removing links, consider an article's place in the knowledge tree. Internal links add to the cohesion and utility of Wikipedia by allowing readers to deepen their understanding of a topic by conveniently accessing other articles. Ask yourself, "How likely is it that someone who reads this article will also want to read that other article?" These links should be included where it is most likely that readers might want to use them; for example, in article leads, the beginnings of new sections, table cells, and image captions.

General linking style points

• As explained in more detail at Help:Links#Wikilinks, linking can be done directly ("[[Riverside, California]]", which results in "Riverside, California"), or through a piped link ("[[Riverside, California|Riverside]]", which results in "Riverside" in the text, but still links to the article "Riverside, California").
• Section headings should not themselves contain links (see WP:ACCESS for the reasons why) - instead a {{main}} or {{seealso}} template should be placed immediately after the heading.
• Links should not be placed in the bold reiteration of the title in the article's lead sentence.
• Generally items within quotations should not be linked; instead, the relevant links should wherever possible be placed in the surrounding text of the article.
• When possible, avoid placing links next to each other so that multiple links look like a single one, as in [[film]] [[actress]] (film actress). Consider rephrasing the sentence, omitting one of the links, or using a more specific single link instead.
• Articles on technical subjects might need a higher density of links than in general-interest articles, due to a larger number of technical terms with precise definitions which cannot be found in general dictionaries.
• Do not create links to user pages, project pages, etc. in articles, except, for example, if the article is about Wikipedia itself (see WP:Self-references to avoid).

Overlinking and underlinking

Provide links that aid navigation and understanding, but avoid cluttering the page with obvious, redundant and useless links. An article is said to be underlinked if subjects are not linked that are helpful to the understanding of the article or its context. However, overlinking is also something to be avoided, as it can make it harder for the reader to identify and follow those links which are likely to be of value.

• Avoid linking to a page that redirects back to the page the link is on.
• Think carefully before you remove a link altogether—what may seem like an irrelevant link to you may be useful to other 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 certain link does not belong in the body of the text, consider moving it to a "See also" section at the bottom of the article; but if the subject fits to be integrated into somewhere in the article rather than into a list at the end of it, it is preferred. (Remember that links can also be useful when applying the "What links here" feature from the target page.)

Some editors feel that the introduction is a special case. On the one hand it might be desirable to have fewer links in this section than in the body of the text; whilst some links make it easier to scan a longer introduction by highlighting key terms, too many make it harder. On the other hand, in technical articles that use many uncommon terms in the introduction, a higher-than-usual link density in the introduction may be necessary to facilitate understanding; but, if possible, try giving an informal explanation in the introduction, avoiding using too many technical terms until later in the article: see point 5 of WP:NOT#Wikipedia is not a manual, guidebook, textbook, or scientific journal, and WP:Make technical articles accessible.

What generally should be linked

In general, links should be created to:

• relevant connections to the subject of another article that will help readers to understand the current article more fully (see the example below). This can include people, events and topics that already have an article or that clearly deserve one, as long as the link is relevant to the article in question.
• articles with relevant information, for example: "see Fourier series for relevant background".
• technical terms, unless they are defined in the article - but always consider providing a concise definition instead of or in addition to a link to another article. If a technical term doesn't have its own article, an interwiki link to Wiktionary may be the most appropriate.
• explicit articles when word usage may be confusing to a non-native speaker (or users of other varieties of English). If the word would not be translated in context with an ordinary foreign-language dictionary, consider linking to an article or Wiktionary entry to help foreign language readers, especially translators. Check the link for disambiguation, and link to the specific item. For example, in A monk was shot in the temple, a non-native speaker unaware of the anatomical meaning of "temple" might not even suspect that in that sentence it does not refer to a religious building. However, when possible, rewording the sentence so that it is unambiguous is preferable.
• articles of geographic places that are likely to be unfamiliar to readers or that in the context may be confused with places that have a similar or identical name.

What generally should not be linked

Unless they are particularly relevant to the topic of the article, it is generally inappropriate to link plain English words and terms whose meaning can be understood by most readers of the English Wikipedia, including the names of major geographic features and locations, religions, languages, common professions, common units of measurement (particularly if a conversion is provided), and dates (but see Chronological items below).

For example, in the article on supply and demand:

• almost certainly link "microeconomic theory" and "general equilibrium", 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 (but since many pages whose title is spelled identically as a common dictionary word are disambiguation pages, make sure that the links are directed to the correct articles: in this example, you should link good (economics), not good);
• do not link to the "United States", because that is a very large article with no explicit connection to supply and demand.
• definitely do not link "potato", 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.

Repeated links

In general, link only the first occurrence of an item. This is a rule of thumb that has many exceptions, including the following:

• where a later occurrence of an item is a long way from the first.
• where the first link was in an infobox or a navbox, or some similar meta-content.
• tables, in which each row should be able to stand on its own.

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. For example, link to "Icelandic alphabet" instead of "Icelandic alphabet": it will contain more detailed information about the Icelandic alphabet, as well as links to the articles "Icelandic language" and "Alphabet". Likewise, use "the flag of Tokelau" rather than "the flag of Tokelau"; in the article about Mozart, link to "[[Requiem (Mozart)|Requiem]]" instead of "[[Requiem]]".

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

• If the topic is one for which a specific article, satisfying the content policies and the notability guidelines, could be written, but it doesn't happen to exist yet, create a redirect page to the article about a more general topic, as described in section {{Section link}}: required section parameter(s) missing: for example, there is no article specifically about electron neutrinos has yet been written; until then, "Electron neutrino" is a redirect to the article "Neutrino", which contains information on all three flavors of neutrinos. If there is no article on a more generic topic, either, create a red link, but read {{Section link}}: required section parameter(s) missing below.
• If the topic is not suitable for a stand-alone article, do not link to a redirect or create a red link; consider linking a more general article instead. For example, instead of the mass of the proton, write the mass of the proton.

If the topic exists as a section of an existing article, then you basically have the same options as above, with the main modification that you append a number sign (#) and the name of the section to the article name to refer directly to the section. Example: Oman#Culture.

If you feel that a certain link does not belong in the body of the text, consider moving it to a "See also" section at the bottom of the article. (Remember that links can also be useful when applying the "What links here" feature from the target page.)

Techniques

Redirects

Main page: WP:Redirect

Let's assume for example you needed a link "poodle", and there was no article for poodles yet. You might want to create a redirect from "poodle" to "dog" as follows: Write the link in the text as if the "poodle" article existed: "She owned a [[poodle]]...". When you save or preview this, you will see "She owned a poodle...". Click on the red link to create the redirect page, enter the target article name (in our case, "Dog"), select that text, and and click the "#R" button. This will create the following text: #redirect [[Dog]].

The advantage of redirects over piped links is that they allow us to determine which pages link to the given topic using Special:Whatlinkshere, which in turn allows us to ...

• create a new article when a significant number of links to that topic exist (see WP:REDIRECT#NOTBROKEN and Redirects with possibilities)
• maintain links, e.g. by filtering incoming links and identifying related articles.

(There is currently no way to apply Whatlinkshere directly to article sections.)

Piped links

Main page: Wikipedia:Piped link

You may want to display a text for a link that is different from the linked article title. This can be achieved with what is called Piped links. Example: [[Henry II of England|Henry II]], which displays as Henry II. However, make sure that it is still clear what the link refers to without having to follow the link. Think about what the reader will believe the link is about. Example: When you use a link such as [[Archery at the 2008 Summer Olympics|Archery]] (which displays as Archery), the reader will expect this link to go to a general article on archery, rather than Archery at the 2008 Summer Olympics. The exception is when it is clear from the the context that links go to specific articles, as in template:2008 Summer Olympics Calendar, where all links go to the article about these specific games.

• Plurals and other derived names. When forming plurals, you can do so thus: [[apple]]s which includes the final "s" in the link like this: apples. This is easier to type and clearer to read in the source text than [[apple|apples]]. This works not just for "s", but for any words that consist of an article name and some additional letters. For details, see Help:Link.

• Case sensitivity. Links are not sensitive to initial capitalization, so there is no need to use piping where the only difference between the text and the target is the case of the initial letter (Wikipedia article titles almost always begin with a capital, whereas the linked words in context often do not). However, links are case-sensitive for all but the initial character.

• Intuitiveness.
  Keep piped links as intuitive as possible. Per the Wikipedia:Principle of least astonishment, make sure that the reader knows what to expect when to click on a link. For example, do not write this:

  Richard Feynman was known for ... as well as work in [[parton (particle physics)|particle physics]].

  The readers will not see the hidden reference to the parton model unless they click on or hover over the piped particle physics link; in hard copy, the reference to partons is completely lost. Instead, reference the article with an explicit "see also" or by rephrasing:

  Richard Feynman was known for ... as well as work in [[particle physics]] (he proposed the [[parton (particle physics)|parton]] model).

• Piping and redirects. Per {{Section link}}: required section parameter(s) missing above, do not use a piped link where it is possible to use a redirected term that fits well within the scope of the text. For example, let's assume the page "Poodle" is a redirect to the page "Dog", and while you're editing some other article, you want to add a link to the word "poodle". You may be tempted to avoid the redirect by directly linking to it with a pipe like this: [[Dog|poodle]]. Instead, write simply [[poodle]] and let the system handle the rest.

Piped links to sections of articles

Linking to particular sections of articles can be useful, since it can take the reader immediately to the information that is most focused on the original topic. If you decided not to use a redirect, you have to use a piped link, because the format "Article name#Section name", is not good enough for display in an article. The format for a subsection link is [[Article#Section|name of link]]. For example, to link to the "Culture" subsection of the Oman article, type [[Oman#Culture|culture of Oman]] (which displays as culture of Oman).

See also Template:Section link.

Links to Wikipedia's categories

Wikipedia has categories of articles like [[Category:Phrases]]; adding this to an article puts it into that category. You can link to a category by putting a colon in front.

For example [[:Category:Phrases]] links to Category:Phrases, and piping can be used Phrases.

Red links

Main page: Wikipedia:Red link

An internal link that displays in red points to a page that does not exist by that name. Some red links come about due to errors (misspelling, or failure to check the exact name of the target article); these should be fixed by correcting the spelling, using a piped link or, if appropriate, creating a redirect. However, many red links are perfectly legitimate, serving to point to an article which may exist in the future, and indeed encouraging editors to create such an article.

Legitimate red links should not be resolved by simply removing the bracket. If a red link is within the context of the article, and it is a topic with the potential to eventually be a neutral, verifiable and encyclopedic article, then the link should be kept. Such links do not have an expiration date, beyond which they must be "fixed". Red links should be removed only if they point to articles that are unlikely ever to be created, such as the names of book chapters, or if they would have little significance in the context of the present article even if they were created.

Red is only the default color for these links for logged-in users, who can change their preferences to select another color.

To make a link more useful to readers when no article currently exists, it may be useful to create a redirect to a relevant existing article or section, or to create a stub for the new article (check similar articles for conventions on naming and categorization).

Checking links as they are created

One of the most common errors in linking occurs when editors do not check to see whether a link they have created goes to the intended location. This is especially true when a mistake is not obvious to the reader or to other editors. The text of links needs to be exact, and many Wikipedia destinations have a number of similar titles. To avoid such problems, which can be irritating for readers, the following procedure is recommended, especially for editors who are new to creating links.

1. Carefully key in the link.
2. Click on "Show preview".
3. In the display-mode, click on the links to check they go where you intend; if they do not, fix them. If a destination page does not appear to exist, do a quick search to determine whether the article has a differently worded title or the subject is treated in a section of another article. Adjust the link accordingly, or leave it as a red link.
4. Return to the "Show preview" page using your browser's return button.
5. Click on "Save page".

By following naming conventions, an internal link will be much more likely to lead to an existing article. When there is not yet an article about the subject, a good link will make the creation of a correctly named article much easier for subsequent writers.

Specific cases

Chronological items

Month-day linking

Month-day articles (February 24 and 10 July) should not be linked unless their content is germane and topical to the subject. Such links should share an important connection with that subject other than that the events occurred on the same date. For example, editors should not link the date (or year) in a sentence such as (from Sydney Opera House): "The Sydney Opera House was made a UNESCO World Heritage Site on 28 June 2007", because little, if any, of the contents of either June 28 or 2007 are germane to either UNESCO, a World Heritage Site, or the Sydney Opera House.

References to commemorative days (Saint Patrick's Day) are treated as for any other link. Intrinsically chronological articles (1789, January, and 1940s) may themselves contain linked chronological items.

Year linking

Year articles (1795, 1955, 2007) should not be linked unless they contain information that is germane and topical to the subject matter—that is, the events in the year article should share an important connection other than merely that they occurred in the same year. For instance, Timeline of World War II (1942) may be linked to from another article about WWII, and so too may 1787 in science when writing about a particular development on the metric system in that year. However, the years of birth and death of architect Philip C. Johnson should not be linked, because little, if any, of the contents of 1906 and 2005 are germane to either Johnson or to architecture.

External links

Main page: Wikipedia:External links

Wikipedia is not a link collection and an article comprising only links is contrary to the "what Wikipedia is not" policy.

Syntax

The syntax for referencing a URL is simple. Just enclose it in single brackets:

[URL link title after space]

The URL must begin with http:// or another common protocol, such as ftp:// or news://.

In addition, putting URLs in plain text with no markup automatically produces a link, for example http://www.example.org/ → http://www.example.org/. However, this feature may disappear in a future release. Therefore, in cases where you wish to display the URL because it is intrinsically valuable information, it is better to use the short form of the URL (host name) as the optional text: [http://www.example.org/ www.example.org] produces www.example.org.

Link titles

Main page: Wikipedia:Embedded citations

You should not add a descriptive title to an embedded HTML link within an article. Instead, when giving an embedded link as a source within an article, simply enclose the URL in square brackets, like this: [http://www.guardian.co.uk/usa/story/0,12271,1650417,00.html] → [1]. However, you should add a descriptive title when an external link is offered in the References, Further reading, or External links section. This is done by supplying descriptive text after the URL, separated by a space and enclosing it all in square brackets.

For example, to add a title to a bare URL such as http://en.luquay.com/ (this is rendered as http://en.luquay.com/), use the following syntax: [http://en.luquay.com/ an open-content encyclopedia] (this is rendered as "an open-content encyclopedia").

Generally, URLs are ugly and uninformative; it is better for a meaningful title to be displayed rather than the URL itself. For example, European Space Agency website is much more reader-friendly than http://www.esa.int/export/esaCP/index.html. There may be exceptions where the URL is well known or is the company name. In this case, putting both the URL and a valid title will be more informative: for example,[http://www.esa.int/export/esaCP/index.html European Space Agency website, www.esa.int.

If the URL is displayed, make it as simple as possible; for example, if the index.html is superfluous, remove it (but be sure to check in preview mode first).

The "printable version" of a page displays all URLs in full, including those given a title, so no information is lost.

URLs as embedded (numbered) links

Without the optional text, external references appear as automatically numbered links: For example,

[http://en.luquay.com/]

is displayed like this:

[2]

When an embedded HTML link is used to provide an inline source in an article, a numbered link should be used after the punctuation, like this, [3] with a full citation given in the References section. See Wikipedia:Cite sources and Wikipedia:Verifiability for more information.

When placed in the References and External links sections, these links should be expanded with link text, and preferably a full citation, including the name of the article, the author, the journal or newspaper the article appeared in, the date it was published, and the date retrieved.

Position in article

Embedded links that are used to support information in an article are positioned in the same manner as any other reference in the article, following the usual standards about citation formatting and placement in relation to punctuation.

Links that are not used as sources can be listed in the External links section, like this:

== External links ==

* [http://

* [http://

As with other top-level headings, two equal signs should be used to mark up the external links heading (see Headings elsewhere in the article). External links should always be the last section in an article. It precedes categories and some kinds of navigation templates.

If there is a dispute on the position of an embedded link, consider organizing alphabetically.

Non-English-language sites

Webpages in English are highly preferred. Linking to non-English pages may still be useful for readers in the following cases:

• when the website is the subject of the article
• when linking to pages with maps, diagrams, photos, tables (explain the key terms with the link, so that people who do not know the language can interpret them)
• when the webpage contains key or authoritative information found on no English-language site and is used as a citation (or when translations on English-language sites are not authoritative).

In such cases, indicate what language the site is in. For example:

• El País, a Spanish-language newspaper from Madrid

You can also indicate the language by putting a language icon after the link. This is done using Template:Languageicon by typing {{Languageicon|<language code>|<language name>}}. For example, {{Languageicon|es}} displays as: Template:Languageicon. Alternatively, type {{xx icon}}, where xx is the language code. For example, {{pl icon}} gives: Template:Pl icon. See Category:Language icon templates for a list of these templates and the list of ISO 639 codes.

File type and size

If the link is not to an HTML or PDF file (the latter is identified automatically by the software with an icon like this: [4]), identify the file type. Useful templates are available: {{DOClink}}, {{RTFlink}}. If a browser plugin is required to view the file, mention that as well.

If the link is to a large file (in the case of HTML, consider the size of the entire page, including the images), a note about that is useful too. Someone with a slow connection may decide not to use it.

Interwiki links

Main pages: Wikipedia:Interlanguage links and Wikipedia:Interwikimedia links

Linking

Interwiki links can take the form of:

[[wiktionary:article]] which appears as: wiktionary:article.

The pipe symbol suppresses the prefix:

[[wiktionary:article|]] → article.

Adding text after the pipe allows different text:

[[wiktionary:article|Any text]] → Any text

Floating boxes

Floating boxes for links to articles in other Wikimedia Foundation projects such as Wiktionary and Wikiquote can be done with special link templates such as {{Wikiquote|Jimmy Wales}}. These will display as a box with a logo. Similar templates exist for some free content resources that are not run by the Wikimedia Foundation. These boxes are formatted in light green to distinguish them from Wikipedia's official sister projects. A list of such templates can be found at Wikipedia:List of templates linking to other free content projects.

Link maintenance

Linking and continual change are both central features of Wikipedia; however, continual change makes linking vulnerable to acquired technical faults and the provision of different information from that which was originally intended. This is true of both "outgoing" links (from an article) and "incoming" links (to an article).

• Outgoing links: These should be checked from time to time for unintended changes that are undesirable; if the opportunity arises to improve their formatting, appropriateness and focus, this should be done.
• Incoming links: Creating an article will turn blue any existing red links to its title (redlinks are usually created in the hope that an article will eventually be written). Therefore, when creating an article, it is wise to check "What links here" to identify such redlinks, if any, and that they are appropriate.

See also

• Help:Contents/Links
• Wikipedia:External links
• Wikipedia:Interlanguage links
• Wikipedia:Interwikimedia links
• Wikipedia:Link color
• Wikipedia:Links to disambiguating pages
• Wikipedia:Links to (disambiguation) pages
• Wikipedia:Linky tutorial
• Wikipedia:Red link
• Wikipedia:Walled garden
• Wikipedia:Dead-end pages, pages without internal links
• Wikipedia:Orphaned articles, pages without incoming links
• Wikipedia:Wikiproject Orphanage
• Wikipedia:WikiProject Integration
• Template:Deadend
• Template:Wikify
• Wikipedia is not an indiscriminate collection of information
• Wikipedia:Allwiki, the idea that every single word should be a link (historical)