Chicago Style Citations: Format Citations as per the Chicago Manual of Style

Here’s something for the humanities and social science researchers out there! If you’ve used style guides like APA or MLA, you know that they give you one citation style to follow: author-date or author-page number, respectively. But the Chicago Manual of Style [1], one of the most authoritative resources for publishers, editors, and authors, offers authors two citation styles to choose from! Which do you choose? And why? We’ve got some answers for you. 

What is the Chicago Manual of Style 

Changes in Chicago Style Formatting Guidelines (18th Edition) 

Types of Chicago Style Citations 

Chicago Reference List Formatting Guidelines 

General Formatting Guidelines in Chicago: Key Aspects 

What is the Chicago Manual of Style?

But first, the basics. What is the Chicago Manual of Style?  

Introduced in 1906, the Chicago Manual of Style, also called CMOS or simply Chicago Style, provides detailed instructions on preparing manuscripts for journal submissions, book manuscripts, essays, and other academic documents. The style guide includes guidelines for grammar usage, punctuation, formatting, citations, and more. The most recent 18th edition of the Chicago style guide was released in September 2024.  

Changes in Chicago Style Formatting Guidelines (18th Edition)

The 18th edition of the Chicago style guide has brought in several key changes in style and format and also introduced new guidance [2]. For example, you will now find clear instructions on handling artificial intelligence (AI) sources and copyright, citing AI-generated images, and the responsibility of authors to specify whether, and to what extent, AI was used in their work. 

Here are a few key changes to note: 

• You can list up to six authors in a reference list entry. For more than six authors, mention the names of first three authors followed by “et al.” 
• Section subheadings can either be in title case or sentence case; but make sure it stays consistent throughout the manuscript. 
• In any given complete sentence, the first letter of the word after a colon should be capitalized. 
• Use the en dash instead of a hyphen when writing compound names (e.g., Runge–Kutta method). 
• The acknowledgements in books can now be placed in the back matter rather than in the front matter. 
• You need not mention the place of publication for books published after 1900. For books published before 1900, the name of the publisher may be excluded; but the date of publication and the city or state of publication should be mentioned.  
• If you’ve used AI-generated content, disclose its use along with generation dates and versions of the tools/platforms used for generating content. 

Types of Chicago Style Citations

Like mentioned earlier, Chicago offers two citation styles for authors to choose. The purpose is to let authors decide which style suits best for their manuscript depending on the discipline. 

Chicago Citation Style 1: Author-Date Style

  
Social science folks, this is the style for you. Your in-text citation consists of the author last names(s), year of publication, and page numbers if the citation accompanies a direct quote. See examples below: 

• (Al-Bahadur 2013) 
• (Laurence, Shah, and Tupsy 2019) 
• According to Duckworth et al. (2020, 65–66), “the absence of any regulatory mechanisms must necessarily result in …” 

When you’re citing a work with four or more authors, your in-text citation has the name of only the first author, followed by “et al.”  (not in italics). 

Chicago Citation Style 2: Notes and Bibliography

Folks specializing in literature, art history, media studies, etc.—you probably have a pretty long paper to write, with lots of citations. Or maybe you’re writing a monograph or a book. Will your readers find it easy to navigate to a single reference list at the end? That’s why the Chicago Manual of Style gives you the option to use the “notes and bibliography” citation style. 

• In-text citations go into footnotes placed at the bottom of every page. 
• Indicate footnotes using a superscript number. 
• Footnote numbers are placed at the end of the sentence after any punctuation mark. 

And at the end, you create a separate Bibliography. 

Chicago style notes can be of two types: 

1. Full Notes: Used the first time you cite a source 

2. Short Notes: For subsequent citations of a source 

Full Notes in Chicago Style 

Full notes provide complete details of the work being cited. 

Here’s an example: 

Mary Gibberyfish, The Little Dog Laughed: Trials of a Kennel Maid, 2nd ed. (London: Goandfindout Press, 2020), 87–98. 

Short Notes in Chicago Style 

Short notes are used when you’re citing the same work as you did earlier in the text. They’re meant to save you time and effort in providing the same details again and again. 

Example: 

Gibberyfish, Little Dog. 121–122. 

Too much work? Just use “ibid.” (= in the same place) when your footnote repeats that appears immediately prior. Even if the page numbers are different, we can still use “ibid.” followed by a comma and then the new page numbers. 

Chicago Reference List Formatting Guidelines

Just like the two citation styles, Chicago guidelines let you list references in two formats: bibliography and reference list. Bibliography is used when you use footnotes as citations, whereas the author-date citation style should always be accompanied by a reference list.  

In both formats, the works cited in the manuscript are listed at the end of the paper, but the difference lies in the placement of the year of publication in each entry. In the reference list, the publication year is written right after the author’s name to match how the in-text citation is displayed in the author-date style. See below examples. 

Bibliography Entry Format

Reference List Entry Format

General Formatting Guidelines in Chicago: Key Aspects

• Use a legible font type and size (e.g., Times New Roman 12 pt). 
• Keep 1-inch margins on all sides of the page. 
• The main text should be left-aligned and follow double line spacing, with each new paragraph beginning with a half-inch indent. 
• Place page numbers either in the top right corner of the page or at the bottom center of the page.  
• No separate title page is required; center the title at the top of the page and then begin writing the main text. If journals or universities ask for a separate title page, follow those guidelines instead.

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References 

1. Chicago-Style Citation Quick Guide https://www.chicagomanualofstyle.org/tools_citationguide.html 

2. What’s new in the 18th edition https://www.chicagomanualofstyle.org/help-tools/what-s-new.html 

Originally published on August 29, 2024. Revised on March 6, 2026