Citation guides

Chicago Style Citation: Author-Date and Notes, with Examples (18th Edition)

Chicago style in both of its systems: author-date citations and the reference list, and notes and bibliography with full and shortened notes. Worked examples for books, journal articles, chapters and websites, what changed in the 18th edition, and the mistakes students carry over from APA.

Ihsan Hossain27 September 2026 9 min read

Chicago style comes from the Chicago Manual of Style, now in its 18th edition (2024). It is really two citation systems under one name, and the first thing to find out is which one your course wants:

Author-date: a short citation in brackets in your text, (Okafor 2021, 45), and a reference list at the end. Common in the sciences and social sciences.
Notes and bibliography: a numbered footnote for each citation and a bibliography at the end. Common in history, the arts and the humanities.

Both share the same building blocks (author, title, publisher, year), so once you know one system the other is mostly a matter of order and punctuation. This guide covers both, with examples you can copy.

Author-date: citations in the text

Give the author's surname and the year, with no comma between them. That missing comma is the easiest way to tell Chicago apart from APA and Harvard. When you point at a specific passage, add the page after a comma, without "p.":

One author

(Okafor 2021)
(Okafor 2021, 45)

Two authors

(Lindqvist and Mensah 2019, 212)

Three or more authors

(Lindqvist et al. 2019)

Two authors are joined with "and", never an ampersand. From three authors, the 18th edition shortens the citation to the first author and "et al.". If the author's name is already part of your sentence, only the year (and page) goes in brackets:

Name in the sentence

Okafor (2021, 45) argues that salt, not gold, financed the early trade.

Organisation as author

(World Health Organization 2023)

No date

(National Trust n.d.)

Two works cited together

(Okafor 2021; Lindqvist et al. 2019)

Author-date: the reference list

Title the list "References", sort it alphabetically by the first author's surname, and use a hanging indent. The year comes straight after the author, which is what makes author-date references easy to match with the citations in your text.

Book

Reference list entry

Okafor, Maria. 2021. Rivers of Salt: Trade and Empire in West Africa.
    University of Chicago Press.

The book title is italicised and capitalised headline-style (every major word). The 18th edition no longer asks for the city of publication, so the publisher alone is enough.

Journal article

Journal article with a DOI

Lindqvist, Erik, Ama Mensah, and Paul Brandt. 2019. "Salt, Credit, and the
    Atlantic Economy." Journal of African History 60 (2): 211–36.
    https://doi.org/10.1017/S0021853719000123.

The article title goes in quotation marks, the journal name in italics, then volume, issue in brackets, and the page range after a colon. End with the DOI as a full link when there is one. Only the first author's name is inverted.

Chapter in an edited book

Chapter

Mensah, Ama. 2020. "Caravans and Credit." In Networks of Exchange, edited by
    Paul Brandt and Lena Holm. Oxford University Press.

The chapter's page range is now optional in the reference list; add it if your instructor wants it.

Website

Web page with a date

National Archives. 2024. "Records of the Colonial Office." March 3, 2024.
    https://www.example.gov/colonial-office.

Web page with no date

National Trust. n.d. "History of the Estate." Accessed June 12, 2026.
    https://www.example.org/estate-history.

Many authors

Name up to six authors in the reference. With seven or more, list the first three followed by "et al.". This rule is the same in author-date and in notes and bibliography.

Notes and bibliography

In this system a superscript number in your text points to a footnote (or endnote). The first time you cite a source, the note gives it in full; after that a shortened note is enough. The bibliography at the end lists every source once.

Full note, book

1. Maria Okafor, Rivers of Salt: Trade and Empire in West Africa
   (University of Chicago Press, 2021), 45.

Shortened note

2. Okafor, Rivers of Salt, 52.

Full note, article with three authors

3. Erik Lindqvist et al., "Salt, Credit, and the Atlantic Economy,"
   Journal of African History 60, no. 2 (2019): 215.

Bibliography

Lindqvist, Erik, Ama Mensah, and Paul Brandt. "Salt, Credit, and the Atlantic
    Economy." Journal of African History 60, no. 2 (2019): 211–36.
    https://doi.org/10.1017/S0021853719000123.

Okafor, Maria. Rivers of Salt: Trade and Empire in West Africa. University of
    Chicago Press, 2021.

Notice the differences from author-date: in a note the author's name is not inverted and the parts are separated by commas; in the bibliography the year moves to the end, and the journal's issue is written "no. 2" instead of "(2)".

Common mistakes

A comma between author and year. That is APA or Harvard. Chicago author-date is (Okafor 2021), not (Okafor, 2021).
Writing "p." before the page. Chicago gives the bare number: (Okafor 2021, 45).
Mixing the two systems. Footnotes and a reference list with years after the authors do not belong together. Pick the one your course uses.
Using an ampersand. Chicago writes "and" between two authors, in the text and in the list.
Listing every author in the text. From three authors, the in-text citation and the note use the first author and "et al.".

Let the details fill themselves in

Paste a link, DOI or ISBN into CitApp's Chicago citation generator and it looks up the author, title, publisher and year, then writes the author-date citation and the reference list entry for you, with "et al." and the comma rules handled. Choose "Chicago Manual of Style 18th edition (notes and bibliography)" as a project's style for a bibliography in the notes system. See also the guides to APA, MLA and Harvard.

Written by Ihsan Hossain

Founder of CitApp, a citation tool built to make source formatting effortless for students. Guides on this blog are checked against the current official style guides (APA 7, MLA 9, and university Harvard variants).

Frequently asked questions

Which Chicago system should I use: author-date or notes and bibliography?

Whichever your course asks for, because both are correct Chicago. As a rule of thumb, history, art history, philosophy and literature use notes and bibliography, while the sciences and social sciences use author-date. If the assignment brief only says "Chicago", ask your instructor, since the two look nothing alike on the page.

What changed in the 18th edition?

For students, three things matter most. A place of publication is no longer needed for books. In notes and in author-date citations, a work with three or more authors is shortened to the first author and "et al.". And in the bibliography or reference list you name up to six authors; with seven or more you list the first three followed by "et al.".

Is Turabian the same as Chicago?

Nearly. Turabian (A Manual for Writers) is the student version of the Chicago Manual of Style, written for papers, theses and dissertations rather than published books. The citation formats follow Chicago. Where they differ, it is usually in paper formatting such as margins and title pages, so follow whichever one your instructor names.

Do I need an access date for websites?

Only when the page shows no publication or revision date. In that case write "n.d." for the year in author-date, and add the date you accessed it at the end of the reference. For a dated page, the access date can be left out.

Can I still use ibid.?

Chicago discourages it and prefers a shortened note instead, because a shortened note still makes sense if notes are later moved or deleted. Some instructors still accept ibid.; if yours does, use it only for a note that cites exactly the same source as the one right before it.