Citing Online Sources: APA, MLA and Chicago Examples

Three style manuals dominate American colleges, and all three answer the same question about web sources differently. A citation that satisfies your psychology instructor can lose points in a literature seminar down the hall, without a single fact changing.

An online source is cited with the author, the publication date, the title of the page, the name of the site and the URL. APA 7 adds a retrieval date only for unarchived pages that are built to change, MLA 9 treats the access date as optional, and Chicago 18 uses it as a fallback.

📌 Key takeaways

• Every web citation needs author, date, title, site and URL.
• APA 7 requires a retrieval date only in narrow exceptions.
• MLA 9 calls the access date optional but encourages it.
• APA wants the archived Wikipedia version carrying an oldid parameter.
• Purdue OWL runs its Chicago pages on the 18th edition.

What counts as an online source, and when can you cite it?

An online source is a text, image, video or dataset published on the web and reachable through a URL, with no print edition carrying its own page numbers. Finding something online does not by itself make it an online source.

The distinction gets missed constantly, and it produces the first wave of broken citations. A journal article stays a journal article after you download the PDF, so it takes volume, issue, page range and, when one exists, a DOI. An ebook stays a book, as our guide to citing books lays out. Genuine online sources are the items that exist only on the web: blog posts, press releases, agency pages, online encyclopedias, statistics portals, videos, forum threads and social media posts.

Whether a source is worth citing at all is the second question. Preferring print on principle no longer holds, because a great deal of reliable material appears online and nowhere else, from federal statistics to court opinions. Three tests settle it instead: a named person or organization is responsible, a specialist can check the content, and the page can be found again reliably. A Wikipedia article fails the first test, which makes it a starting point rather than evidence.

The six parts of a citation for a web page

A complete citation for a web page has six parts: author, date, title, name of the site, URL and, depending on the style, the date you accessed it. Order and punctuation differ across the three manuals, the six parts do not.

All six sit on the page itself or on its about page. Collecting them in that order before you format anything saves rework. Anyone who formats first and hunts afterward tends to miss the last-updated date, which many content management systems park at the very bottom of the page.

For the author, an organization steps in when no person is named, so a federal agency or a university takes the slot. APA adds a shortcut: when author and site name are identical, the site name drops out. Only when no responsible party exists does the title move to the front.

For the date, the last-updated date beats the original publication date, because the version you read is the version you cite. APA asks for year, month and day where all three appear, and falls back to the year alone.

Where APA, MLA and Chicago disagree about the access date

The three American style manuals answer the access date question in three different ways, and the disagreement is real rather than a matter of emphasis. Carrying the rule of one manual into another produces a formal error that costs points.

APA 7, MLA 9 and Chicago 18 revise on separate schedules, and the access date is where the three timetables collide most visibly.

Status: August 2026, subject to change.

Purdue OWL states the APA rule in one line: retrieval dates are required for unarchived sources that are likely, or intended, to change over time. The same page adds that APA 7 no longer requires the use of Retrieved from before URLs or DOIs, with special exceptions made for resources that are unarchived. Both sentences come from the APA electronic sources guide.

For MLA the wording is markedly softer, and what follows is a paraphrase rather than a quotation. Purdue OWL says MLA uses Accessed to mark the date you reached the page, that doing so is not required and that it is encouraged where no copyright date is listed. The same page then contradicts itself: its section on citing an entire web site states that the phrase Accessed is no longer used. Both passages sit in the MLA electronic sources guide.

⚠️ Watch out

An access date never substitutes for a missing publication date. Where both are gone, mark the entry n.d. in APA and check whether a firmer source carries the same claim.

Citing online sources: worked examples in three styles

Three systems cover almost every American assignment, and each arranges the same six parts differently. All three examples below use one source: the Pew Research Center study on disappearing web content, published on May 17, 2024.

One warning saves a lot of rework, because citation systems are closed. APA puts author and year in parentheses in the running text, MLA puts author and page there, and the notes and bibliography version of Chicago sends the whole citation to the foot of the page. Mixing two systems in one paper is the most common formal error of all. The groundwork is in our guide to correct citing.

Citing a web page in APA 7

APA 7 opens with author and full date, italicizes the title of the page, names the site and closes with the bare URL and no final period. No retrieval date belongs here, because the page carries a fixed publication date. The list at the end of an APA paper is called the Reference List, and its counterpart in Harvard style is covered in our guide to the Harvard citation style.

Reference List: Chapekis, A., Bestvater, S., Remy, E., & Rivero, G. (2024, May 17). When online content disappears. Pew Research Center. https://www.pewresearch.org/data-labs/2024/05/17/when-online-content-disappears/

In-text citation: (Chapekis et al., 2024)

Citing a web page in MLA 9

MLA 9 puts the title of the article in quotation marks, italicizes the name of the site, and follows with the publication date and the location. Purdue OWL contradicts itself on the protocol: one passage says MLA only requires the www. address and that you should eliminate all https:// when citing URLs, while a later table on the same page calls omitting the protocol outdated for work submitted online. The list is called Works Cited.

Works Cited: Chapekis, Athena, et al. “When Online Content Disappears.” Pew Research Center, 17 May 2024, www.pewresearch.org/data-labs/2024/05/17/when-online-content-disappears/. Accessed 27 Aug. 2026.

In-text citation: (Chapekis et al.)

Citing a web page in Chicago 18

Chicago 18 runs two systems, and the notes and bibliography version is the one used in history and the humanities. The note carries the author, then the title in quotation marks, the site name, the date and the URL, while the bibliography entry inverts the name of the first author and lists the remaining three in full. Purdue OWL moved its Chicago pages to the 18th edition, so any guide still labeled 17th describes a superseded manual.

Note: Athena Chapekis et al., “When Online Content Disappears,” Pew Research Center, May 17, 2024, https://www.pewresearch.org/data-labs/2024/05/17/when-online-content-disappears/.

Bibliography: Chapekis, Athena, Sarah Bestvater, Emma Remy, and Gonzalo Rivero. “When Online Content Disappears.” Pew Research Center, May 17, 2024. https://www.pewresearch.org/data-labs/2024/05/17/when-online-content-disappears/.

Special cases: Wikipedia, databases, email, social media, AI chat

Special cases in online citation follow one logic: when a part is missing, the next most important part moves up, and the gap gets marked rather than passed over. Nothing may be invented, including a year that looks right.

Seven cases cover most of what shows up in a term paper or a thesis. Your syllabus overrides each of them where it differs.

• Wikipedia in APA: link the archived version rather than the live page. Open View History, click the date stamp, and take the URL with the oldid parameter.
• Database article without a DOI: APA leaves out the URL and any database information. ERIC and UpToDate are the exceptions.
• Email: personal communications never appear in an APA Reference List and are cited in the text alone, as in (E. Robbins, personal communication, January 4, 2001).
• No author: put the organization in the author slot. Where none is identifiable, the entry starts with the title of the page.
• Video: the uploader is the author, the upload date is the date, and a timestamp pins a specific claim.
• Social media post: profile name and handle, date, the first twenty words as the title, and the permalink of the post.
• Dictionary entry: a continuously updated reference work takes n.d. and a retrieval date, because no fixed version exists.

Output from a language model deserves its own sentence, because the rules have moved every year since 2023. Such output cannot be reproduced or checked by anyone else, so most institutions ask for a disclosure rather than a citation. Whether your program allows a citation, demands a disclosure or bans the tool is set out in your academic integrity policy. What follows a violation is covered in our guide to the plagiarism check.

Is there a binding standard for citing online sources?

No national standard governs citation in the United States, and the three dominant manuals are private publications owned by an association or a university press. Each one revises on its own schedule, which is exactly why the rules drift apart.

Purdue OWL, the most widely used free reference in American higher education, tracks those revisions and shows the drift plainly. Its Chicago section moved to the 18th edition, its APA section runs on the 7th, and its MLA section runs on the 9th, with a separate archive kept for APA 6. Three manuals on three separate clocks produce the access date conflict all by themselves.

The regular case for you is straightforward: the binding rule is whatever your instructor, department or graduate school sets out. The exception is the case where no guidance exists at all, and you then pick one established manual and apply it consistently. Authority to interpret the rule rests with your instructor, never with a guide on the web. This article does not replace academic advising.

Grades follow consistency, not the choice of manual.

Dead links: why the URL alone is not enough

A URL is a state rather than a permanent address. Research by the Pew Research Center from May 2024 found that 38 percent of the web pages that existed in 2013 were unreachable ten years later.

For a thesis the decay is a practical problem: if someone checks your sources a year after submission, the page may be gone. Pew also found that 23 percent of the news pages sampled carried at least one dead link, and that more than half of the Wikipedia articles sampled had at least one dead reference. Three tools help against it, and none of them costs anything.

• DOI: a Digital Object Identifier points at a document permanently, even after the publisher moves the address. Crossref asks for the form https://doi.org/10.xxxx in its display guidelines.
• Version links: many platforms mint an address for one fixed version, and Wikipedia does it through the oldid parameter that APA asks for.
• Web archive: the Wayback Machine of the Internet Archive stores a version of the page at its own dated address, and linking to it is expressly allowed.

💡 Tip

Save every online source on the day you access it with the Save Page Now function of the Wayback Machine, and note the archive address beside your citation. A screenshot in your own files costs nothing and settles arguments later.

Common mistakes when citing online sources

Most points lost on online sources come from haste in the final days before the deadline rather than from ignorance. Four mistakes recur often enough to be worth a targeted check.

The repairs take minutes each. Running the check once across the whole list is faster than working through it entry by entry.

Citing the home page instead of the exact page

A citation has to lead to the page the claim sits on. Giving the home page of the site instead forces the reader to search and defeats the purpose of the entry. Statistics portals and agency sites are the worst offenders, because their front pages change daily. Take the address of the specific page, and prefer the permalink wherever the site offers one.

Breaking a URL with a hyphen

A URL is never broken with a hyphen, because the hyphen might belong to the address and makes the link unusable. Break long addresses after a forward slash instead, or switch off automatic hyphenation for the entry. Shortening services solve nothing either, since they can be switched off and they hide where the source came from.

Using the copyright year in the footer as the publication date

The year in the footer belongs to the site as a whole rather than to the individual page, so it is not a publication date. Taking it over dates a text from 2019 to 2026 by accident. Look for the date on the article itself, check for a last-updated note, and use n.d. when nothing at all can be found.

Splitting online sources into a separate list

A separate list for web sources alone appears in none of the three manuals and makes looking things up harder, because the reader has to search twice. Where your instructor demands one, follow the syllabus. Without such a rule, every source belongs in one alphabetical list, whether your manual calls it a Reference List, Works Cited or a bibliography.

Conclusion

Citing online sources rests less on rule knowledge than on care while collecting the six parts. Settle first which manual your course requires, gather author, date, title, site name and permalink while you read, and archive the page before it disappears. Add the access date only where your manual asks for it, which in APA means a narrow set of unstable pages.

One habit carries the whole job: build the citation while the page is still open in front of you, not in the week of the deadline. APA, MLA and Chicago all reward the same discipline, and each of them punishes a list assembled from browser history.

Where to go next

• Starting from the basics? Correct citing: the full guide
• Citing books and ebooks? How to cite books correctly
• Writing the whole thesis? Bachelor thesis: guide and structure

Do you need your own data instead of somebody else's web pages?

Your own survey is never cited as an online source, because it becomes your own dataset. With empirio.ai, an online survey tool from Germany, you can build one free of charge. How to structure the questions is set out in our guide to creating a questionnaire.