Chicago Style 18th Edition: Notes-Bibliography and Author-Date

The Chicago Manual of Style (CMOS), published by the University of Chicago Press, is now in its 18th edition (2024). Unlike most guides, it offers two complete citation systems.

The two systems carry nearly the same information; what changes is order and punctuation, above all the position of the year. Your department or journal decides which to use. The reference generator offers both.

1. What changed in the 18th edition

From CMOS's official What's New list, the changes that affect citations most:

• Number of authors: in a bibliography or reference list, give up to six authors; for seven or more, list the first three plus et al. (13.23, 13.107). In notes and author-date text citations, give up to two names; with three or more, use the first author plus et al.
• No place of publication for books (14.30). Books published before 1900 may still cite a place instead of a publisher.
• Repeat the author's name for consecutive entries rather than using a 3-em dash (13.72, 13.113).
• Months and seasons can usually be omitted from journal citations (13.26).
• Chapter page ranges are no longer required in list entries (14.8); journal article ranges still are.
• Newspapers in author-date: when the entry has a month and day, the year is not repeated (14.89): 2023. … New York Times, December 13.
• Terminology: "headline style" is now title case and "sentence style" sentence case; prepositions of five letters or more are capitalized in titles (8.159–60).
• Family-name-first names (Liu Xinwu) are not inverted in a list and take no comma (13.75). This is useful for Korean names.

2. Authors

• In the list: invert only the first author; give names as they appear: Binder, Amy J., and Jeffrey L. Kidder.
• Three to six: list all. Seven or more: Snyder, Carl D., Manuel Bedrossian, Casey Barr, et al.
• In notes: normal order; two names joined by and; three or more as Carl D. Snyder et al.
• Organizations go in the author position (Google; Wikimedia Foundation).
• No author: begin with the title; in author-date, the title takes the author's place before the year.
• Editors: eds. in list entries, ed. in notes, and "edited by" for the book containing a chapter.

3. Dates, titles, DOIs and page ranges

• With no date, use n.d. and add an access date (Accessed March 8, 2022). A public archived copy, such as a Wayback Machine link, may be cited instead.
• Access dates are otherwise not required for dated sources.
• English titles take title case. Books, journals, newspapers and websites are italic; articles, chapters and web pages go in “quotation marks.” In the 18th edition, news sites and other websites that function as books or periodicals are italicized too (8.193–94).
• Give DOIs as URLs beginning https://doi.org/; otherwise give a URL or database name. Chicago ends a URL with a period.
• Join page ranges with an en dash and abbreviate the second number following CMOS 9.64:

The official examples follow it: 471–85, 1818–59, 225–51.

4. Author-date system

In-text citations

• (Author Year, page), with no comma between author and year: (Yu 2020, 45).
• Two authors: (Binder and Kidder 2022, 117–18). Three or more: (Snyder et al. 2025, 9–10).
• Distinguish same-author, same-year works as 2023a, 2023b.

Reference list

• Title it References (or Works Cited); alphabetize by surname, then by year.
• Use hanging indents; line spacing follows your school or publisher. Theses often single-space within entries and add a blank line between them.

These entries come from the CMOS Citation Quick Guide (author-date). A generated table of author-date examples by source type appears below this guide.

Yu, Charles. 2020. Interior Chinatown. Pantheon Books.

Kwon, Hyeyoung. 2022. “Inclusion Work: Children of Immigrants Claiming Membership in Everyday Life.” American Journal of Sociology 127 (6): 1818–59. https://doi.org/10.1086/720277.

Snyder, Carl D., Manuel Bedrossian, Casey Barr, et al. 2025. “Extant Life Detection Using Label-Free Video Microscopy in Analog Aquatic Environments.” PLOS ONE 20 (3): e0318239. https://doi.org/10.1371/journal.pone.0318239.

Blum, Dani. 2023. “Are Flax Seeds All That?” New York Times, December 13. https://www.nytimes.com/2023/12/13/well/eat/flax-seeds-benefits.html.

Yale University. n.d. “About Yale: Yale Facts.” Accessed March 8, 2022. https://www.yale.edu/about-yale/yale-facts.

5. Notes and bibliography system

In NB, a superscript number in the text points to a footnote or endnote, and a Bibliography closes the work.

• First note, full form: names in normal order, elements separated by commas, book publication facts in parentheses, cited page at the end.
• Later notes, short form: surname, short title (up to four words), page. The 18th edition prefers short forms to ibid.; the author-title form is the default (13.37).
• Bibliography entry: first author inverted, elements separated by periods, no parentheses; journal entries give the full page range.

The same book in all three forms, from the CMOS Citation Quick Guide (notes and bibliography):

1. Charles Yu, Interior Chinatown (Pantheon Books, 2020), 45.

3. Yu, Interior Chinatown, 48.

Yu, Charles. Interior Chinatown. Pantheon Books, 2020.

A journal article. The note cites the page used; the bibliography gives the whole range. Volume and issue appear as "127, no. 6 (2022)".

1. Hyeyoung Kwon, “Inclusion Work: Children of Immigrants Claiming Membership in Everyday Life,” American Journal of Sociology 127, no. 6 (2022): 1842–43, https://doi.org/10.1086/720277.

5. Kwon, “Inclusion Work,” 1851.

Kwon, Hyeyoung. “Inclusion Work: Children of Immigrants Claiming Membership in Everyday Life.” American Journal of Sociology 127, no. 6 (2022): 1818–59. https://doi.org/10.1086/720277.

First notes for a chapter in an edited book and for a dissertation:

1. Kathleen Doyle, “The Queen Mary Psalter,” in The Book by Design: The Remarkable Story of the World’s Greatest Invention, ed. P. J. M. Marks and Stephen Parkin (University of Chicago Press, 2023), 64.

1. Yuna Blajer de la Garza, “A House Is Not a Home: Citizenship and Belonging in Contemporary Democracies” (PhD diss., University of Chicago, 2019), 66–67, ProQuest (13865986).

6. Key differences by source type

• Journal article: volume, issue, pages — 127 (6): 1818–59 in author-date; 127, no. 6 (2022): 1818–59 in NB.
• Book: publisher and year; no place. Editions as 2nd ed.
• Chapter: "In Book Title, edited by …"; the chapter's page range is optional in the list.
• Thesis or dissertation: title in quotation marks, then "PhD diss., University" or "Master's thesis, University," plus database and ID.
• Web page: page title in quotation marks, site name roman (italic if it functions as a book or periodical); access date only when undated.
• Report: treat like a book, with the issuing body as publisher and any report number after the title.
• Newspaper or magazine: page numbers may appear in notes or text but are omitted from the list; add a URL or database for online copies.
• Conference paper: title in quotation marks, followed by the meeting name, place and date (e.g., "Paper presented at …"). In notes, the 18th edition no longer puts this information in parentheses (14.115).

7. Mixing Korean and English sources

Korean humanities journals use footnote systems close to Chicago NB, but house rules take priority and differ in detail: 『』 for Korean books and 「」 for articles, page labels such as 쪽 or 면, and repeat citations with 위의 책 or 앞의 글 — unlike Chicago's preference for short forms. When romanizing Korean names written family name first, CMOS 13.75 lets you keep them uninverted. See the Korean journal guide and the in-text citation guide.

8. Common mistakes

• Mixing NB and author-date in one paper — pick one.
• A comma in an author-date citation: (Yu, 2020) should be (Yu 2020).
• Following the 17th edition's ten-author rule — list six, or three plus et al. for seven or more.
• Spelling out three authors in a note — use the first author plus et al.
• Adding a city of publication — no longer needed.
• Using note punctuation in the bibliography — notes use commas and parentheses; the bibliography uses periods.
• Repeating the year in an author-date newspaper entry.
• Writing 1818–1859 — shorten to 1818–59.
• Access dates on dated pages — add them only for undated sources.

Check English titles with the title case tool.

Examples by source type — Chicago 18th (author-date)

These examples are generated by this site's formatting engine from fictional sample data (not real publications).

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Chicago 18th (notes-bibliography)

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