TL;DR

• Chicago style has two systems: Notes-Bibliography and Author-Date.

• Humanities papers typically use footnotes and a bibliography.

• Science and social science papers typically use in-text citations.

• Every source type, books, articles, websites, has its own format.

• Getting citations right protects your credibility as a researcher.

You have finished your research paper. The argument is solid. The evidence is strong. Then you reach the citations section and everything slows down. Which format goes where? Does the author name come first? Does the page number need a comma or a colon? Chicago style trips up even experienced writers because it has two distinct systems, and most guides do not explain clearly which one applies to you.

This guide cuts through that confusion. It covers both Chicago systems, explains when to use each one, and walks through the most common source types step by step. It is written for student researchers who want to get citations right the first time, whether you are submitting to a class, a competition, or a peer-reviewed journal.

Understanding citation format is one part of a larger skill set that academic publishing demands. If you want a broader view of how to write and submit research, the Publication Compass guide to the academic publishing process is a good place to start.

What is Chicago style and when should you use it?

Chicago style is a citation and formatting system published by the University of Chicago Press. It is defined in The Chicago Manual of Style, now in its 17th edition. Researchers in history, literature, philosophy, and the arts most commonly use it, though some social science and science fields use a variation of it as well.

Chicago style is the dominant citation format in historical research. Journals like The Journal of American History and The American Historical Review both require Chicago-style footnotes and bibliographies for submitted manuscripts. If you are writing in the humanities and planning to submit your work for publication, learning Chicago style is not optional. It is a baseline expectation.

The reason Chicago style persists is practical. Footnotes let a writer add context, explain a source, or flag a disagreement without interrupting the main argument. That flexibility suits complex historical and philosophical writing in a way that parenthetical citations often do not.

How to cite sources in Chicago style: the two systems explained

Chicago style offers two citation systems. The Notes-Bibliography system uses footnotes or endnotes plus a bibliography at the end of the paper. The Author-Date system uses short in-text citations plus a reference list. Choosing the wrong system for your field is a common and avoidable mistake.

Use Notes-Bibliography if you are writing in history, literature, art history, music, or most other humanities disciplines. Use Author-Date if you are writing in the social sciences, natural sciences, or any field where your department or target journal specifies it. When in doubt, check the submission guidelines of the journal or program you are writing for. The guidelines will name the system explicitly.

Both systems require the same core information: author name, title of the work, publication details, and a page number where relevant. The difference is in how and where that information appears on the page.

If you are working toward journal submission and want structured support identifying the right format for your target publication, joining the Publication Compass waitlist gives you early access to a platform built specifically for student researchers navigating exactly this kind of decision.

How to format footnotes and bibliography entries in Chicago style

In the Notes-Bibliography system, a footnote appears at the bottom of the page where you cite a source. The bibliography appears at the end of the paper and lists every source you cited. The two entries for the same source look slightly different from each other, which is where many students make errors.

Here is how the format works for the most common source types:

1. Book (single author): Footnote: First name Last name, Title of Book (Place of Publication: Publisher, Year), page number. Bibliography: Last name, First name. Title of Book. Place of Publication: Publisher, Year.

2. Journal article: Footnote: First name Last name, "Article Title," Journal Name volume, no. issue (Year): page number. Bibliography: Last name, First name. "Article Title." Journal Name volume, no. issue (Year): page range.

3. Website: Footnote: First name Last name, "Page Title," Website Name, Month Day, Year, URL. Bibliography: Last name, First name. "Page Title." Website Name. Month Day, Year. URL.

Notice that footnotes use commas between elements and end with a page number. Bibliography entries use periods between elements and list the full page range for articles. That distinction is consistent across every source type in the Notes-Bibliography system.

A practical tip: write your footnotes as you draft, not after. It is far easier to record the author, title, publisher, year, and page number while the source is open in front of you than to reconstruct it later from memory or a browser history.

How to cite sources in Chicago style using the Author-Date system

In the Author-Date system, you place a short citation directly in the text of your paper, inside parentheses, immediately after the relevant sentence. The citation contains the author's last name, the publication year, and a page number if you are quoting directly. A full reference list at the end of the paper provides the complete details.

The in-text citation looks like this: (Smith 2019, 45). The reference list entry for the same source looks like this: Smith, Jane. 2019. Title of Book. Place of Publication: Publisher.

For journal articles in the Author-Date system, the reference list entry follows this order:

1. Author last name, first name.

2. Year of publication.

3. "Article title in quotation marks."

4. Journal Name in italics volume number (issue number): page range.

5. DOI or URL if available.

The Author-Date system is cleaner on the page for papers with many citations, which is why science and social science fields prefer it. If you are submitting to a journal like PLOS ONE, which publishes across scientific disciplines and accepts student research, the Author-Date format will feel more familiar because it resembles the APA (American Psychological Association) format many students already know.

Common Chicago citation mistakes and how to avoid them

Most Chicago citation errors fall into a small number of repeating patterns. Knowing them in advance saves significant revision time.

The first mistake is using the footnote format in the bibliography or vice versa. These are not interchangeable. The footnote is a shortened, comma-separated entry. The bibliography entry is a fully punctuated, period-separated entry with the last name first. Many students copy a footnote directly into their bibliography and lose marks for it.

The second mistake is omitting the place of publication for books. Chicago style requires it. For books published after roughly 2010, many publishers operate across multiple cities, and the manual advises using the city listed on the title page. Do not guess.

The third mistake is mishandling subsequent footnotes. If you cite the same source twice in a row, Chicago style allows you to use "Ibid." followed by a page number if the page differs. If you cite the same source again after citing other sources in between, use a shortened note: Last name, shortened title, page number. Do not repeat the full footnote entry each time.

For student researchers writing their first research paper, understanding citation conventions is closely tied to understanding how academic writing works at a structural level. The Publication Compass blog covers the research writing process from draft to submission in detail.

How to cite digital and online sources in Chicago style

Digital sources follow the same logic as print sources, with two additions: a URL or DOI (Digital Object Identifier), and an access date for sources that may change over time. The University of Chicago Press recommends including a DOI wherever one exists, because DOIs are permanent links while URLs can break.

For an online journal article with a DOI, the bibliography entry in Notes-Bibliography format looks like this: Last name, First name. "Article Title." Journal Name volume, no. issue (Year): page range. https://doi.org/XXXXXXX.

For a webpage with no identified author, begin with the title of the page. For a social media post, include the platform, the username, the date, and the URL. The 17th edition of The Chicago Manual of Style addresses social media citations directly, reflecting how much research now draws on digital primary sources.

One reliable free resource for checking your Chicago format is the official quick guide published by the University of Chicago Press at chicagomanualofstyle.org. It covers the most common source types and is updated to reflect the current edition of the manual.

FAQ: How to cite sources in Chicago style

What is the difference between Chicago style footnotes and endnotes?

Footnotes appear at the bottom of the page where the citation occurs. Endnotes appear in a numbered list at the end of the paper or chapter. Both use the same formatting. Most journals and instructors prefer footnotes because they are easier to read alongside the main text. Check your submission guidelines to confirm which is required.

How do you cite a source with no author in Chicago style?

Begin the citation with the title of the work instead of an author name. In footnotes, use a shortened version of the title after the first full citation. In the bibliography, alphabetise the entry by the first significant word of the title, skipping articles like "A," "An," and "The."

How do you cite sources in Chicago style for a research paper submitted to a journal?

Check the journal's author guidelines first. Most humanities journals specify Notes-Bibliography format. Some require a particular edition of the manual. The guidelines will also tell you whether to use footnotes or endnotes and whether a bibliography is required in addition to notes. Following these instructions exactly is part of the submission process.

Does Chicago style require a bibliography if you use footnotes?

Yes, in most cases. The Notes-Bibliography system uses both. Footnotes give the reader immediate citation information. The bibliography gives a complete, alphabetised list of all sources for reference. Some shorter papers or book chapters may omit the bibliography if the footnotes are comprehensive, but for journal submission, include both unless instructed otherwise.

How do you cite a book chapter in an edited volume in Chicago style?

Cite the chapter author first, then the chapter title in quotation marks, then "in" followed by the book title in italics, the editor's name preceded by "ed.," and the publication details. For example: Last name, First name. "Chapter Title." In Book Title, edited by Editor Name, page range. Place: Publisher, Year.

Getting citations right is worth the effort

Citation format is not a bureaucratic hurdle. It is a signal to editors and readers that you understand how academic knowledge is built and attributed. A paper with clean, consistent Chicago citations reads as more credible before an editor even reaches the argument. That matters when you are submitting to a competitive journal or a selective research program.

Take the time to learn both Chicago systems. Use the official quick guide from the University of Chicago Press to check your work. And if you are navigating the broader process of writing, formatting, and submitting a research paper as a student, the Publication Compass platform is designed to help you move from draft to submission with structured, specific feedback at every stage.