Chicago Style Citation Guide: Notes, Bibliography & Author-Date

What Is Chicago Style?

Chicago style is a citation and formatting system published by the University of Chicago Press. The first edition of the Chicago Manual of Style appeared in 1906, making it one of the oldest and most authoritative style guides in English publishing. The current edition — the 17th — was published in 2017 and remains the standard reference for professional publishing, academic journals in the humanities and social sciences, and many university programmes.

Chicago style is most commonly required in history, literature, art history, philosophy, musicology, religion, and some branches of the social sciences. It is also the standard used by many book publishers and journals outside academia. If you are writing a history paper, a thesis in the humanities, or submitting to an academic press, Chicago is the style you need.

Unlike APA or MLA, Chicago style does not have a single citation format. It offers two distinct systems that serve different academic communities, and understanding which one applies to your work is the first step to using Chicago correctly.

Two Systems: Notes-Bibliography vs Author-Date

Chicago's two systems differ fundamentally in how they present source information in the text and in the bibliography.

If your assignment or institution does not specify which system to use, ask. Many professors in history departments default to Notes-Bibliography; social science researchers often prefer Author-Date. This guide covers both systems in depth.

Footnotes and Endnotes

In the Notes-Bibliography system, every source you cite receives a superscript number in the text. The full citation appears either at the bottom of the page (footnote) or at the end of the paper before the bibliography (endnote). Both are acceptable; check your instructor's preference. Most word processors insert footnotes automatically using Ctrl+Alt+F (Word) or Insert → Footnote.

Full (First) Note Format

The first time you cite a source, provide complete bibliographic information in the note:

Notice the formatting differences from bibliography entries: in footnotes, the author's name appears in normal order (First Last); page numbers follow directly; and parentheses enclose publication details for books.

Shortened Subsequent Notes

After the first full note, subsequent references to the same source use a shortened form: author's last name, shortened title, and page number.

Ibid.

Ibid. (from the Latin ibidem, meaning "in the same place") can be used when successive notes cite the same source. Use Ibid. alone if citing the same page, or Ibid., 56 for a different page. Many style guides, including the Chicago Manual, now recommend using shortened notes instead of ibid. to avoid confusion when notes are renumbered during revision — but ibid. remains acceptable.

Chicago Bibliography Formatting

The bibliography in the Notes-Bibliography system lists every source cited in your notes, arranged alphabetically by the author's last name. It differs from footnotes in several important ways:

• Author name is inverted: Last name, First name (opposite of footnotes)
• No parentheses around publication details for books
• Hanging indent: First line flush left; subsequent lines indented 0.5 inches
• No page numbers for journal articles (you give the full page range, not the specific page cited)
• Periods separate the main elements (author, title, publication info) rather than commas

Footnote vs Bibliography: Same Source, Different Format

Citing Books

One Author — Footnote / Bibliography

Multiple Authors

Edited Book

Translated Book

Chapter in an Edited Anthology

Citing Journal Articles

Print Journal Article

Online Article with DOI

Citing Websites

Web Page with Corporate/Organisation Author

Web Page with No Author

Note that access dates are required for websites in Chicago Notes-Bibliography, because web content can change or disappear. Always record the date you viewed a page.

Citing Newspapers and Magazines

Newspapers and magazines follow a similar structure to journal articles, but the volume and issue numbers are typically omitted. The date serves as the primary locator.

Newspaper Article (Print)

Newspaper Article (Online)

Author-Date In-Text Citations

The Author-Date system replaces footnotes with parenthetical citations embedded in the prose. These follow the same author–year format as APA, though the punctuation details differ slightly.

Basic Format

Author Named in Sentence

Multiple Authors

Multiple Works in One Citation

List sources alphabetically by author, separated by semicolons:

Author-Date Reference List

The Author-Date reference list is titled "References" (not "Bibliography") and follows formatting very similar to APA, but with important differences in punctuation and the placement of the publication year.

Book

Journal Article with DOI

Web Page

Chicago vs APA vs MLA: Key Differences

Use Bibloq to Generate Chicago Citations

Chicago's two-format system is genuinely complex: the same source needs different formatting in the footnote and the bibliography, the first full note looks different from subsequent shortened notes, and the Author-Date reference list format differs from the Notes-Bibliography bibliography in subtle but important ways.

Bibloq generates both the footnote entry and the bibliography entry simultaneously for the Notes-Bibliography system. For Author-Date, it produces the in-text citation and the reference list entry together. You will never again need to manually invert an author's name, decide where parentheses should go, or remember whether the year comes before or after the publisher.

Enter a DOI, ISBN, or URL. Select "Chicago Notes-Bibliography" or "Chicago Author-Date." Copy the output directly into your paper or bibliography manager. The formatting is verified against the 17th edition of the Chicago Manual of Style.