The two main reasons for splitting material out from an article are size and content relevance. If either the whole article, or the specific material within one section becomes too large, or if the material is seen to be inappropriate for the article due to being out of scope, then a split may be considered or proposed. Consideration must be given to size, notability and potential neutrality issues before proposing or carrying out a split.

Articles should be neither too big nor too small.

It may benefit the reader to consider moving some sections to new articles and replace them with summaries per Wikipedia:Summary style. Consideration, however, needs to be given to the amount and quality of material to be moved. If the material for the new article is too short to provide encyclopedic coverage of the subject, or would simply duplicate the summary that would be left behind, then it may be too soon to move it. Unsourced material shouldn't be used to create new articles as it may have notability or verifiability issues.

Word counts can be found with the help of XTools (also accessible via Page History from Page Statistics link at the top) under "Prose" in the "General statistics" section; Shubinator's DYK tool; or Prosesize.

These guidelines apply somewhat less to disambiguation pages and do not apply to redirects. They also apply less strongly to list articles, especially if splitting them would require breaking up a sortable table.

Too large after templates are expanded:

After all templates and transclusions are accounted for, the resulting post-expand include size may reach a limit. This can look like templates lower in the page, such as the {{reflist}} or navigation templates, not displaying properly. One solution is to split the article.

Since undoing a split may be labor-intensive if significant editing happens to either page after the split, try to avoid splitting until after a community discussion. If there is another way to reduce the "post-expanded size" that is easier to "undo" than a split, consider doing it first, then opening a discussion to see what the long-term fix should be.

Likewise, if a split would be controversial, try to find a less controversial way to temporarily reduce the "post-expanded size" then open a discussion to find consensus for a long-term fix.

However, if splitting the page is the easiest-to-undo solution and such a split would not be controversial, consider being bold and splitting the page, then immediately opening a discussion to see if the community accepts the split or if it offers alternative solutions. In this case, be prepared to undo the split.

Sometimes two or more distinct topics may share the same base title or similar titles, such as "light", which may refer to electromagnetic radiation, a component that produces light, or spiritual illumination. Sometimes the distinct topics may be closely related, such as Coffea (the plant) and coffee (the product), or thermal energy and heat.

When two or more distinct topics with the same or a similar titles are being written about on the same page, even if they are closely related, a content split may be considered, and a disambiguation page created to point readers to the separate pages. Before proposing a split, consideration must be given both to notability of the offshoot topic and to potential neutrality issues. If one or more of the topics is not notable on its own, it may be more appropriate to simply remove the material from Wikipedia than to create a new article.

If unsure, start a discussion on the article's talk page using a template.

Note: For disambiguation pages, use {{Split dab}} instead of {{split}}. If section to be split out is known, use {{split section}}.

If an article meets the criteria for splitting and no discussion is required, editors can be bold and carry out the split. If unsure, or with high-profile or sensitive articles, start a "Split" discussion on the article talk page, and consider informing any associated WikiProject(s). Additionally, adding one of the splitting templates will display a notice on the article and list it at Category:Articles to be split. This will help bring it to the attention of editors who may assist in establishing consensus, in deciding if a split is appropriate, or in carrying out the split. Templates used without an accompanying rationale, and where there is no obvious reason for the split request, may be removed at any time.

Note: To comply with Wikipedia's licensing requirements, which require that all content contributors receive attribution, the page receiving the split material must have an edit summary noting "split content from [[article name]]". (Do not omit this step or omit the page name.) A note should also be made in the edit summary of the source article, "split content to [[article name]]". The {{Copied}} template can also be placed on the talk page of both articles. For further information, refer to the main Copying within Wikipedia guideline.

Skip to step 5 if making a bold split. Create a discussion on the talkpage of the page that content is to be split from. Include what sections are to be split and what the new page name should be. Example:

== Splitting proposal ==

I propose that the section about blinker liquids be split into a separate page called [[Blinker fluid]]. The content of the section is only marginally related to the main article, and this section is large and well-sourced enough to make its own page. ~~~~

Notify involved users (optional): To generate a discussion and to notify people who know a lot about the topic, it is recommended to contact involved users. These users can be: frequent contributors, the creator of the page or users who have a lot of posts on the talk page. You can notify them by {{ping |USER1|USER2|...}} or by using a notice for their talk page {{Subst:Splitnote | ARTICLE NAME | NEW ARTICLE NAME | TALK PAGE}}.

Failure to reach a consensus, whether the result of a split discussion or a bold split that was contested, usually results in the article remaining whole. A contested bold split may be reverted; however it is not always appropriate to redirect the new article to the old as the new article may stand on its own, even if the main article that it came from is not split.

Use {{split}} to notify users of the proposed split. On the article (not the talkpage) add {{split|Article 1|date=December 2024}} or {{split|Article 1|Article 2|...|date=December 2024}}. This template adds a box to notify users about the split. If the new page name is unknown, use {{split}} by itself with no parameters.

In many cases, a hybrid discussion/straw poll is used, but remember that polling is not a substitute for discussion.

Example formatting:

 * '''Support''' – <insert reason for supporting split here> ~~~~
 * '''Oppose''' – <insert reason for opposing split here> ~~~~

During discussion, a rough consensus may emerge to proceed with the split. Any user, including the user who first proposed the split, may close the discussion and move forward with the split if enough time (normally one week or more) has elapsed and there has been no discussion or if there is unanimous consent to split. Closing of split discussions differs from closing of requested move discussions in that closings of uncontroversial split discussions by involved users are allowed. Admin tools are not needed unless page protection prohibits editing.

In more unclear, controversial cases, the determination that a consensus to split has or has not been achieved should be made by an editor who is neutral and not directly involved in the split proposal or the discussion. If necessary, a request that an administrator, who is not involved, close the discussion can be made at the Requests for Closure noticeboard.

To close a split proposal discussion, the {{Discussion top}} and {{Discussion bottom}} templates are used in the following manner:

== Split proposal ==

{{Discussion top|result=The result of this discussion was to ... ~~~~}}

<Start of discussion>
.
.
.
<End of discussion>

{{Discussion bottom}}

See below. This is the most important step!

If material is split from an article, consider whether a summary section should be created, and whether a {{Main}} template should be placed at the top of the section to link to the new page. In general, if the split is due to size, then a summary section is required; if the split is due to content (or scope), then a summary section is unlikely to be required. On the talk page of the new and old articles, include the template {{Copied}}.

The following procedure can be used for splitting from a single source article to a new article. These instructions are provided for guidance, but some steps may not be necessary in all cases and these instructions may not cover every eventuality. It is advisable to read through the whole of this procedure before starting.

1. If the material you want for the new article is scattered around the source article, then prepare the source article by grouping the material to be split out into a single section. Save your changes with an edit summary like "preparing to split article".
2. Create the new article by opening the empty page (or redirect page).
3. Open the source article (or relevant section) to edit in another browser window (or tab) and copy the contents to be split out (from the section created in step #1) from the source article.
4. Paste into the new article with edit summary "Contents [[WP:SPLIT]] from [[Source article name]]; please see its history for attribution." and save the new article.
5. Tidy up the new article:
   • The lead sentence will need to be changed to use bold font and usually includes a link to the source article.
   • A References section should be added and categories should be added. There may also be sections of a bibliography, navboxes, See also section or External links that can be copied from the source article.
   • Adjust section headings.
   • Add any background information about the parent subject that will be necessary for the reader to understand the subtopic.
   • Resolve any cite errors that occur when invocations of a named reference are separated from their definition – i.e. copy the relevant information from the source article.
6. Create a good summary of the subtopic at the parent article.
   • Add "{{Main|new article name}}" (use the order: image, main tag, text). If all the content of the section is being removed (e.g. in the case of a list) use the "See" template instead of the "Main" template. Use the edit summary "Material [[WP:SPLIT]] to [[New article name]]" and save the edit.
   • Add a summary, usually of a couple of paragraphs and one image, of the newly created subtopic (unless complete removal is appropriate). Alternatively, with a strong lead paragraph in the new article, use an excerpt template to replace the section: {{Excerpt|Page title}}
   • There may be some external links, bibliography items, etc. that can be removed from the source article as they are now in the new article.
7. Check Special:WhatLinksHere to see whether some inlinks to the source article (especially any that were to the section that has been split off) can now be changed to point to the new article.
8. (Optionally) Add templates referring to the split to the talk pages:
   • If the new article is not being created from scratch (e.g. there is already a redirect), then go to the new article, click on 'View history' tab, select the edit where the copy was made, open it and copy the diff URL of the edit where the cut was made from the browser URL window.
   • If the new article is being created from scratch, it's a bit more complicated to obtain a diff URL – see Template:Copied.
   • Open the source article talk page to edit in a new tab.
   • Add template {{Copied|from=|from_oldid=|to=|to_diff=}} to source article talk page, and paste the diff URL into it, add the title of the new article and the date, add a descriptive edit summary and save the edit.
   • Open the new (destination) article talk page to edit in a new tab.
   • Add template {{Copied|from=|from_oldid=|to=|to_diff=}} to the new article talk page, and paste the diff into it, add the title of the source page and the date, add a descriptive edit summary and save the edit.
   • On the talk page of the new article, you can put the {{SubArticle}} or {{Summary in}} tag to create a banner that refers back to the main article.
9. (Optionally) Put WikiProject tags on the new article's talk page.
10. (If possible) Connect the new article to any corresponding articles in other Wikipedias – see Interwiki.

If you or another editor split an article without adding the correct attribution, follow the procedure at WP:RIA to add attribution afterwards.

There are a number of templates that can be used on articles and their talk pages as part of splitting articles.

A list of articles that have been tagged for consideration for splitting are at Category:Articles to be split.

• Wikipedia:Proposed article splits
• Wikipedia:Naming conventions (lists) § Long (split) list naming recommendations
• Wikipedia:Summary style
• Wikipedia:Merging
• Wikipedia:Content forks – there are acceptable and unacceptable content forks. Know the difference.
• Lumpers and splitters