Chicago Citation Style: The Complete Reference Guide for 2026
The Chicago citation style is one of the oldest and most authoritative citation systems in scholarly publishing. Maintained by the University of Chicago Press, the Chicago Manual of Style (CMOS) is now in its 17th edition and underpins citation practice across history, philosophy, theology, the arts, and many social sciences. What makes Chicago distinctive — and sometimes confusing — is that it offers two parallel systems: the Notes-Bibliography (NB) style, preferred in the humanities, and the Author-Date (AD) style, preferred in the natural and social sciences.
This 2026 guide covers both Chicago systems in full, with annotated examples for every major source type, a clear comparison of when to use NB versus AD, and the most common errors to avoid in each system.
Notes-Bibliography vs. Author-Date: When to Use Each
| Feature | Notes-Bibliography (NB) | Author-Date (AD) |
|---|---|---|
| In-text marker | Superscript number¹ | (Author Year, Page) |
| End matter | Bibliography | Reference List |
| Primary disciplines | History, art history, theology, philosophy, literature | Sociology, psychology, economics, political science, natural sciences |
| Flexibility for commentary | High — notes can contain additional discussion | Low — parenthetical only |
| Reading flow impact | Notes interrupt body text minimally | Parenthetical interrupts prose slightly |
When in doubt, check your department’s style guide or ask your supervisor. If the source is ambiguous (e.g., a history of science paper), NB is generally the safer default for humanities-oriented journals.
The Notes-Bibliography System
In the NB system, a superscript number in the body text (¹) directs the reader to a footnote at the bottom of the page or an endnote at the end of the chapter or paper. The note contains the full citation on first mention; subsequent mentions of the same source use a shortened form. A complete Bibliography appears at the end of the paper, listing all sources alphabetically by author’s last name.
Note vs. Bibliography Format
The format of a footnote and a Bibliography entry differs in three key ways:
- Author name order: Notes use first-name-last-name order (John Smith). Bibliography uses last-name-first order (Smith, John).
- Punctuation: Notes use commas between elements; Bibliography entries use periods.
- Page numbers: Notes cite specific pages; Bibliography entries cite the full page range of articles or chapters.
First Note vs. Shortened Note
First (full) footnote — Book:
1. John Smith, The Politics of Memory (Oxford University Press, 2022), 47.
Subsequent (shortened) note:
2. Smith, Politics of Memory, 52.
The abbreviation “Ibid.” (meaning “in the same place”) was standard in older Chicago style. CMOS 17 still permits it but discourages it in favour of shortened titles, which are unambiguous if notes are rearranged during revision.
The Author-Date System
In the Author-Date system, sources are cited parenthetically within the text. The citation includes the author’s last name, the publication year, and (for direct quotes or specific references) a page number: (Williams 2023, 47). The Reference List at the end of the document provides full bibliographic information, identical in content to the NB Bibliography but formatted slightly differently (the year moves to immediately after the author’s name).
Multiple works in one citation are separated by semicolons and listed in chronological order or alphabetically: (Adams 2020; Brown 2023; Chen 2024). When the author is already named in the sentence, only the year and page number appear parenthetically: Williams (2023, 47) argues that…
Citing Books in Chicago Style
NB System — Book
Footnote: Author First Last, Title of Book (Place of Publication: Publisher, Year), page.
Example: Rebecca Solnit, A Field Guide to Getting Lost (New York: Penguin, 2005), 22.
Bibliography: Author Last, First. Title of Book. Place of Publication: Publisher, Year.
Example: Solnit, Rebecca. A Field Guide to Getting Lost. New York: Penguin, 2005.
AD System — Book
In-text: (Solnit 2005, 22)
Reference List: Solnit, Rebecca. 2005. A Field Guide to Getting Lost. New York: Penguin.
Edited Books
NB Bibliography: Last, First, and First Last, eds. Title. Publisher, Year.
Chapter in edited book (NB footnote): Author First Last, “Chapter Title,” in Book Title, ed. Editor First Last (Publisher, Year), pages.
Citing Journal Articles
NB — Journal Article
Footnote: Author First Last, “Article Title,” Journal Title Vol, no. Issue (Year): pages. DOI or URL.
Example: James Mitchell, “Colonial Memory and Postcolonial Identity,” Journal of Historical Sociology 36, no. 2 (2023): 114–130. https://doi.org/10.xxxx/xxxxx.
Bibliography: Mitchell, James. “Colonial Memory and Postcolonial Identity.” Journal of Historical Sociology 36, no. 2 (2023): 114–130. https://doi.org/10.xxxx/xxxxx.
AD — Journal Article
In-text: (Mitchell 2023, 114)
Reference List: Mitchell, James. 2023. “Colonial Memory and Postcolonial Identity.” Journal of Historical Sociology 36 (2): 114–130. https://doi.org/10.xxxx/xxxxx.
Note that in the AD Reference List, the issue number appears in parentheses immediately after the volume number — a distinctive formatting difference from NB.
Citing Websites and Online Sources
NB — Website
Footnote: Author First Last, “Page Title,” Site Name, Month Day, Year, URL.
Example: Emma Thompson, “The Archive in the Age of AI,” British Library, February 14, 2025, https://www.bl.uk/articles/archive-ai.
Bibliography: Thompson, Emma. “The Archive in the Age of AI.” British Library. February 14, 2025. https://www.bl.uk/articles/archive-ai.
AD — Website
In-text: (Thompson 2025)
Reference List: Thompson, Emma. 2025. “The Archive in the Age of AI.” British Library. February 14. https://www.bl.uk/articles/archive-ai.
For websites likely to change or disappear, include an access date: “Accessed March 15, 2026.”
Special Source Types
Theses and Dissertations
NB Footnote: Author First Last, “Title” (PhD diss., University Name, Year), page.
NB Bibliography: Last, First. “Title.” PhD diss., University Name, Year.
Archival Documents
Chicago NB is particularly well-suited to archival research, where sources may be unpublished letters, manuscripts, and institutional records. The general format includes: document description, date, collection name, box/folder numbers, repository name, and location.
Legal and Government Documents
Chicago follows The Bluebook for legal citations. For US legislation: Act Title, Public Law Number, Statutes at Large Citation (Year). For UK legislation: cite the Act name, chapter number, and year as it appears in official publications.
Paper Formatting Rules
- Font: A readable serif or sans-serif font, 12pt (Times New Roman or similar).
- Margins: 1 inch on all sides.
- Spacing: Double-spaced body text; single-spaced footnotes.
- Footnote separator: A short rule separates the text from footnotes at the bottom of each page.
- Headings: Chicago does not prescribe a rigid heading hierarchy for student papers; follow journal or department guidelines.
- Title page: Standard for Chicago-style academic papers — include paper title, author name, course, institution, and date.
Common Chicago Style Errors
- Using the wrong system for your discipline. History = NB. Economics = AD. When unsure, ask.
- Mixing first-note and shortened-note formats. Use the full format on first mention only; use the shortened form every time after.
- Reversing author name order. Footnotes use first-name-last order; Bibliography uses last-name-first.
- Wrong punctuation. Footnotes: comma-separated. Bibliography: period-separated.
- Omitting place of publication. Chicago NB still requires city and publisher for books; APA 7 does not.
- Misusing ibid. If you continue to use it, ensure it refers unambiguously to the immediately preceding note.
- Forgetting the access date for mutable websites. Add “Accessed Day Month Year” for pages that change frequently.
Frequently Asked Questions
What edition of the Chicago Manual of Style should I use?
The current edition is the 17th (2017), which remains the active standard in 2026. The University of Chicago Press updates the online version (CMOS Online) continuously. For most student papers, the 17th edition rules apply. Always check whether your journal, publisher, or institution specifies a particular edition.
What is the difference between a footnote and an endnote in Chicago style?
Both footnotes and endnotes serve the same citation function in the NB system. Footnotes appear at the bottom of the page on which they are referenced; endnotes are collected at the end of the chapter or document. Journals typically prefer footnotes for easy reading; book publishers often require endnotes to keep page layout clean. For student papers, footnotes are more common. The citation format is identical in both cases.
Does Chicago style require a Bibliography if I use footnotes?
In most cases, yes. When using the NB system, a Bibliography at the end of the paper (or chapter) is expected. Some instructors and journals accept footnote-only citations without a separate Bibliography, but this is the exception. Always check submission requirements. A Bibliography provides a complete, alphabetically organised reference list that readers can scan quickly — it serves a different purpose from the note-by-note citations in the text.
How do I cite a source with no author in Chicago style?
For the NB system, begin the footnote and Bibliography entry with the title of the work. In the Bibliography, alphabetize by the first significant word of the title (ignoring A, An, The). For the AD system, use the title (shortened if long) in the in-text citation in place of the author name, followed by the year: (Global Report 2024, 12).
Does Chicago style use “p.” before page numbers?
No. Chicago style does not use “p.” or “pp.” before page numbers in footnotes or reference lists. Simply write the page numbers directly: “Smith, History of Ideas, 47″ or “114–130.” This differs from APA, which uses “p.” for single pages and “pp.” for ranges in certain contexts.
When should I use a Bibliography versus a Reference List in Chicago?
Use a Bibliography with the Notes-Bibliography (NB) system. Use a Reference List with the Author-Date (AD) system. They are functionally similar — both provide full bibliographic details for all cited sources — but their formats differ slightly. A Bibliography may also include sources you consulted but did not directly cite; a Reference List typically includes only sources cited in the text.
Continue Building Your Citation Expertise
Fluency in Chicago citation style takes practice across multiple source types. For broader citation training, explore our guides on APA citation format, MLA format guide, and Harvard referencing. If you are working in a STEM or social science context, the Vancouver citation style guide is also essential reading. Tesify Write supports Chicago NB and AD formatting to keep your citations consistent throughout your thesis or dissertation.
For peer resources in German, visit tesify.io, which offers comprehensive academic writing guidance tailored to German-speaking universities.
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