If an article becomes too large, or a section of an article has a length that is out of proportion to the rest of the article, it is often appropriate for some or all of the article to be split into new articles

If an article becomes too large, or a section of an article has a length that is out of proportion to the rest of the article, it is often appropriate for some or all of the article to be split into new articles. In some cases, refactoring an article into child or sister articles can allow subtopics to be discussed more fully elsewhere without dominating a general overview article to which they are non-central (but only if the new articles are themselves sufficiently notable to be included in the encyclopedia).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.Large articles may have readability and technical issues. A page of about 30 to 50 kilobytes (kB) of readable prose, which roughly corresponds to 6,000 to 10,000 words, takes between 30 and 40 minutes to read at average speed, which is right on the limit of the average concentration span of 40 to 50 minutes. Also, some users may have technical limitations, such as a low speed service, an unstable connection, a pay per kilobyte service, or they may access Wikipedia through a mobile phone or smartphone, and these mobile browsers may truncate long pages.At 50 kB of readable prose and above 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.Below 50 kB, an article may not need splitting based on size alone, and at 40 kB and below a split would generally only be justified based on content issues.These guidelines apply somewhat less to disambiguation pages and naturally do not apply to redirects. They also apply less strongly to list articles, especially if splitting them would require breaking up a sortable table.Sometimes two or more distinct topics may share the same or similar title, 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 which share the same or similar title 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. Consideration must be given both to notability and to potential neutrality issues before proposing a split. If one or more of the topics is not notable it may be more appropriate to simply remove the material from Wikipedia than to create a new article.If unsure, then use a template, and start a discussion on the article talkpage.If an article meets the criteria for splitting, 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.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.To conform with Wikipedia's licensing requirements, which require that 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]]". It is a requirement of Wikipedia's licensing that attribution be given to the main content author(s). The {{Copied}} template can be placed on the talk page of both articles for this purpose. For further information, refer to the main Copying within Wikipedia guideline.If material is split from an article, consider if a summary section should be created, and if a {{Main}} template should be placed 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.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 the through the whole of this procedure before starting.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.