How to Cite in Chicago Style: Complete 18th Edition Guide

This guide will help you understand how to properly cite sources in Chicago format, the versatile citation style used across history, arts, and publishing, ensuring that your academic work meets the standards outlined in the Chicago Manual of Style's latest edition.

The Official Source

The Chicago Manual of Style, 18th Edition is published by the University of Chicago Press and available in hardcover and online at chicagomanualofstyle.org. The Press announced the edition on April 16, 2024, telling CMOS Online subscribers they would "get the new online edition automatically in September."

The manual itself is behind a subscription, so every example below is taken from the two free resources the Press publishes: the Citation Quick Guide and the CMOS Q&A.

Two Citation Systems

Chicago offers two documentation styles:

• Notes-Bibliography (NB) — preferred in humanities (history, literature, arts)
• Author-Date — preferred in sciences and social sciences

This guide covers the Notes-Bibliography system, which uses footnotes or endnotes plus a bibliography.

Notes-Bibliography: Quick Overview

When you cite a source:

• Place a superscript number after the relevant text¹
• Include the full citation in a footnote or endnote
• List all sources in a bibliography at the end

Footnote vs. Bibliography Format

Footnotes and bibliography entries differ slightly in format. The examples below are the Citation Quick Guide's own, reproduced as the Press publishes them.

Book

Key differences: footnotes use first name first with commas; bibliographies invert the first author's name and use periods. Note that the publisher stands alone — the 18th edition dropped the city of publication.

Common Source Examples

Journal Article

The footnote pinpoints the pages being used; the bibliography gives the article's full range.

Chapter in Edited Book

Note the abbreviation: "ed." in the note, "edited by" spelled out in the bibliography.

Website

One small departure: the Quick Guide's note line for this source reads "effective November 15," with no year, while its bibliography entry gives "Effective November 15, 2023." The year is supplied in the note above, since a reader needs it.

Newspaper Article

Key 18th Edition Changes

The University of Chicago Press listed these changes when it announced the edition:

• No place of publication — "A city or other place of publication will no longer be required when citing books (e.g., Pantheon Books, 2024, not New York: Pantheon Books, 2024)."
• Preposition capitalization — "In titles of works, prepositions of five or more letters will now be capitalized (A Room with a View but Much Ado About Nothing)."
• Generic singular "they" — "will now be considered acceptable even in formal writing—for example, when the antecedent is an indefinite pronoun (someone forgot their coat)."
• Initial "The" retained — kept in running text for periodicals whose title includes it (The New York Times and The American Naturalist but the Chicago Tribune).

Separately, the CMOS Q&A gives a format for citing text generated by an AI tool, on the pattern "Text generated by ChatGPT, OpenAI, January 10, 2026, URL."

Shortened Citations

After citing a source once in full, use a shortened form for subsequent references:

The Quick Guide illustrates repeated citations this way rather than with "ibid." — a sensible default for electronic formats, where notes may not appear in sequence.

Common Mistakes to Avoid

• Commas vs. periods — use commas between elements in footnotes; use periods in bibliography entries
• Author name order — first name first in footnotes; last name first in bibliography (only for the first author)
• Page numbers — include specific pages in footnotes; include full page range in bibliography
• Quotation marks vs. italics — article and chapter titles in quotes; book, journal, and website titles in italics
• Multiple authors — in bibliography, invert only the first author's name

Who Uses Chicago Style?

Chicago is the standard for history, art history, philosophy, religion and theology, some social sciences, and the publishing industry.

Many academic presses and scholarly journals require Chicago style. Students in these fields should master both the Notes-Bibliography and Author-Date systems.

Several disciplinary styles are Chicago author-date with a short house sheet on top, so if your department names one of these, read it alongside this page rather than instead of it: AAA for anthropology, which defers to Chicago for anything its own guide does not specify, and APSA for political science, which follows the Chicago Manual and adds rules for government documents and legal sources. ASA, for sociology, is author-date too but its own standard, with a colon before page numbers.

Chicago vs. Turabian

A Manual for Writers by Kate Turabian presents a simplified version of Chicago style designed for students. Turabian and Chicago are largely compatible, but always check which your instructor requires. Our Turabian guide covers the 9th edition, which aligns with Chicago 17.

Further Resources

• Chicago Manual of Style Online — subscription-based access with Q&A
• CMOS Citation Quick Guide — free quick reference
• Purdue OWL Chicago Guide — free comprehensive resource