Chicago Style: 18th Edition Citation & Format Guide

What is Chicago style?

Chicago style is a broad editorial style system covering much more than citations. The Chicago Manual of Style includes guidance on manuscript preparation, grammar, punctuation, capitalization, numbers, quotations, source citations, indexing, publishing, and other editorial matters.

For students and researchers, however, “Chicago style” often refers specifically to how sources are cited and how a paper is formatted.

The current edition is the 18th edition, published in 2024. Chicago reorganized its citation guidance in this edition and changed several rules that affect authors, books, chapters, journal articles, and bibliographies.

This website focuses primarily on Chicago 18th-edition source citation. For a focused summary of the edition changes, see Chicago 18th Edition: What Changed.

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What are the two Chicago citation systems?

Chicago has two parallel systems for documenting sources:

1. Notes & Bibliography
2. Author-Date

They use many of the same source details, such as author, title, publisher, journal, and publication year, but they place that information differently.

Feature	Notes & Bibliography	Author-Date
Citation in the text	Superscript note number	Parenthetical author + year
Detailed citation	Footnote or endnote	Reference-list entry
Repeated source	Shortened note	Another parenthetical citation
End-of-paper list	Usually bibliography	Reference list
Common use	Humanities	Sciences and social sciences
Typical locator	Page or other locator in note	Page or other locator after year

The official Chicago Citation Quick Guide recommends following the system used in your field or required by your publisher. Students who are unsure should ask their instructor.

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Which Chicago system should I use?

Use the instructions for your assignment or publication first.

A quick way to identify the required system is to look for these signals:

Use Notes & Bibliography if you are asked for:

• footnotes;
• endnotes;
• superscript note numbers;
• full notes and shortened notes;
• a Chicago bibliography.

This system is especially common in history, literature, the arts, and other humanities fields.

Read the complete Chicago Notes & Bibliography guide for the full workflow.

Use Author-Date if you are asked for:

• parenthetical citations;
• author-year citations;
• citations such as (Yu 2020, 45);
• a Chicago reference list.

This system is common in the sciences and social sciences.

See the Chicago Author-Date guide for detailed in-text and reference-list rules.

What if the assignment only says “Chicago style”?

Do not guess based only on the word “Chicago.” Check the assignment sheet, syllabus, journal instructions, or your instructor’s requirements.

If the directions mention footnotes or endnotes, they are pointing toward Notes & Bibliography. If they show author-year citations in parentheses, they are pointing toward Author-Date.

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How does Chicago Notes & Bibliography work?

The Notes & Bibliography system connects a superscript number in the text to a numbered footnote or endnote.

A source may appear in three forms:

1. a full note;
2. a shortened note for a later citation;
3. a bibliography entry.

Example: book in Notes & Bibliography

Full note

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

Shortened note

1. Yu, Interior Chinatown, 48.

Bibliography entry

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

The page number in the note identifies the part of the book being cited. A later citation can point to a different page without changing the source itself.

For detailed rules on full notes, shortened notes, note numbers, footnotes, endnotes, and locators, see Chicago Footnotes.

For bibliography ordering and formatting, see Chicago Bibliography.

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What is the difference between a full note and a shortened note?

A full note gives enough source information to identify the work when it is cited in full. A shortened note reduces that information for later citations of the same source.

The standard Chicago short form is typically based on the author and a shortened title, followed by the relevant locator when needed.

For example:

Full note

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

Shortened note

Yu, Interior Chinatown, 48.

Chicago 18 also clarifies that shortened citations used instead of ibid. may take author-title, author-only, or title-only forms depending on the context. The author-title short form is the regular Chicago form and is the clearest default for most users.

The Chicago Footnotes guide covers shortened notes in more depth.

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How does a Chicago bibliography work?

A Chicago bibliography is the end-of-paper source list normally associated with Notes & Bibliography.

Entries are generally arranged alphabetically by the first author’s surname. The author’s name is normally inverted at the beginning of the entry, and bibliography entries use different punctuation from notes.

For the book above:

Note

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

Bibliography

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

A bibliography entry describes the source as a whole, while the note can identify the particular page, chapter, section, or other location being cited.

See Chicago Bibliography for alphabetical order, hanging indents, multiple authors, repeated authors, and other bibliography mechanics.

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How does Chicago Author-Date work?

The Author-Date system places a short citation directly in the text, normally using the author’s surname and publication year. A corresponding full entry appears in a reference list.

A specific page or other locator can follow the year.

Example: book in Author-Date

In-text citation

(Yu 2020, 45)

Reference-list entry

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

If you cite a different page later, the source record remains the same:

(Yu 2020, 48)

The Chicago Author-Date guide explains multiple authors, missing dates, locators, reference-list order, and other common cases.

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Is a Chicago bibliography the same as an Author-Date reference list?

No. They perform a similar end-of-paper function, but they belong to different Chicago systems and are formatted differently.

A bibliography normally belongs to Notes & Bibliography.

A reference list belongs to Author-Date.

One of the easiest differences to notice is the placement of the year.

Notes & Bibliography bibliography

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

Author-Date reference list

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

Do not mix the punctuation and ordering conventions from the two systems in the same source list.

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How are page numbers and other locators used in Chicago citations?

A locator tells the reader where in a source the cited material appears.

Common locators include:

• page;
• page range;
• chapter;
• section;
• paragraph;
• volume;
• figure;
• line;
• document number;
• timestamp.

The locator belongs to the individual citation, not necessarily to the permanent source record.

For example, the same book might be cited as:

• page 45 in one note;
• page 48 in another note;
• chapter 6 in another citation.

This distinction matters when using a citation generator. The Chicago Citation Generator lets you keep the source details while changing the cited location for the citation you are creating.

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What information does a Chicago citation need?

The required metadata depends on the source type.

Book

Common elements include:

• author or editor;
• book title;
• edition, when relevant;
• publisher;
• publication year;
• URL, database, or ebook format when relevant.

See the Chicago Book Citation guide.

Journal article

Common elements include:

• article author;
• article title;
• journal title;
• volume;
• issue;
• publication year;
• article page range or article number;
• DOI or other appropriate online location.

See the Chicago Journal Article Citation guide.

Website or webpage

Depending on the page, useful details may include:

• author or organization;
• page title;
• website owner or sponsor;
• publication or revision date;
• access date when needed;
• URL.

See the Chicago Website Citation guide.

Chapter in an edited book

Common elements include:

• chapter author;
• chapter title;
• book title;
• editor or editors;
• publisher;
• publication year;
• specific cited page in a note or in-text citation when needed.

See the Chicago Book Chapter Citation guide.

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What changed in Chicago 18th edition citations?

The 18th edition introduced several citation changes that can make older examples misleading.

Author thresholds changed

For a bibliography or reference-list entry:

• list up to six authors;
• with more than six authors, list the first three followed by “et al.”

For a note or an Author-Date text citation:

• list up to two authors;
• with more than two authors, use the first author followed by “et al.”

Publication place is no longer normally required for modern books

A modern book citation generally no longer needs a city before the publisher.

For example:

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

rather than automatically adding a place of publication.

Chapter page ranges changed

Chicago 18 no longer requires the full page range of a chapter or other contribution to an edited book in a standard bibliography or reference-list entry.

A specific page can still be important when you cite a particular passage in a note or Author-Date citation.

Journal month or season can usually be omitted

For journal articles, a month or season can now usually be left out of the citation.

Repeated author names are normally repeated

Chicago now prefers writing the author’s name again in a bibliography or reference list rather than replacing a repeated name with a 3-em dash.

Shortened citations were clarified

Chicago 18 clarifies the available forms for shortened citations and continues to support shortened notes as a practical alternative to repeated full citations.

See the dedicated Chicago 18th Edition guide for the changes that matter most when moving from 17th-edition examples.

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How do Chicago 18 author rules work?

Author handling depends on both the number of authors and the citation system.

Number of authors	Note	Author-Date in-text	Bibliography / reference list
1	List the author	List the author	List the author
2	List both	List both	List both
3–6	First author + et al.	First author + et al.	List all authors
7+	First author + et al.	First author + et al.	First 3 + et al.

These thresholds are especially important because many older Chicago guides still reflect 17th-edition rules.

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How are titles formatted in Chicago style?

Chicago formatting depends on the type of work.

As a general pattern:

• titles of books and journals are italicized;
• titles of journal articles, book chapters, and many shorter works appear in quotation marks.

Capitalization and punctuation can vary by source type and context, so use the relevant source guide rather than applying one template to everything.

For verified examples across several sources, see Chicago Citation Examples.

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Should I include a DOI or URL in a Chicago citation?

For online scholarly articles, a DOI-based URL is generally preferred when one is available. Other online sources may require a URL, database name, or another access description depending on the source.

A DOI is valuable because it identifies the scholarly work rather than only the webpage where you happened to find it.

For journal-specific guidance, see Chicago Journal Article Citation. For webpages, see Chicago Website Citation.

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When does Chicago use an access date?

An access date is particularly useful when a webpage has no publication or revision date and a formal citation is needed.

The official Chicago examples show undated webpage citations using an access date. An archived version of the page may also be cited in appropriate cases.

Do not add an access date automatically to every online source. The need depends on the source and the information available.

The Chicago Website Citation guide covers dates, website owners, URLs, archived pages, and undated content.

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What does Chicago format mean for a student paper?

“Chicago format” can mean two different things:

1. citation format, such as Notes & Bibliography or Author-Date;
2. paper layout, such as margins, page numbers, headings, notes, and the final source list.

The Chicago Manual of Style is primarily an editorial and publishing manual. The official Chicago website provides separate student resources for research-paper setup and points students to Chicago-compatible student guidance.

For a class paper, your instructor, department, university, or dissertation office should take priority if it specifies margins, title-page design, spacing, font, heading levels, page numbering, or other layout requirements.

Do not assume that every document using Chicago citations must have one identical visual layout.

For this site, detailed source-citation rules remain the primary focus. The Chicago Style Citation Examples page shows the citation forms, while the system-specific guides explain how they work.

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What are the most common Chicago citation mistakes?

Mixing the two Chicago systems

A bibliography-style entry should not be combined with Author-Date in-text citations unless your specific publisher or instructor requires an unusual hybrid.

Choose one system and use it consistently.

Copying a 17th-edition template

Older templates may still include a publication city for modern books or use outdated author thresholds.

Check that the guidance is actually based on Chicago 18.

Treating the bibliography and reference list as identical

Their purpose is similar, but the formatting differs, especially around the placement of the year.

Using a full note every time without checking the required workflow

Chicago provides shortened citations for subsequent references. Your assignment or publisher may also specify how notes should be handled.

Saving a page number as permanent source metadata

A page number may describe where you cited something, not the source as a whole. Keep locators separate when you expect to cite the source more than once.

Trusting imported metadata without reviewing it

DOI, ISBN, webpage, and title searches can save time, but external metadata can be incomplete or ambiguous. Review author names, titles, dates, editions, publication details, and identifiers before using the citation.

Adding an access date to every URL

Some online sources need access dates, but not every source does. Check what publication or revision information is available first.

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Chicago citation examples by source type

The exact structure changes with the source.

Use these dedicated guides when you need the full templates and examples:

• Chicago Book Citation
• Chicago Journal Article Citation
• Chicago Website Citation
• Chicago Book Chapter Citation

For side-by-side examples covering both systems, go to Chicago Citation Examples.

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Generate a Chicago 18th-edition citation

If you already have your source, you do not need to format every element manually.

Use the Chicago Citation Generator to:

• search by DOI, URL, ISBN, title, or other supported input;
• review and edit the retrieved metadata;
• choose Notes & Bibliography or Author-Date;
• add a page or another citation-specific locator;
• copy a full note, shortened note, bibliography entry, in-text citation, or reference-list entry;
• save sources to a bibliography or reference list.

The source details remain reviewable so you can correct incomplete or inaccurate metadata before using the result.

For details about lookup sources, CSL formatting, source normalization, duplicate handling, and limitations, read How the Chicago Citation Generator Works.

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Frequently asked questions

Is Chicago style the same as footnotes?

Not always. Chicago Notes & Bibliography uses footnotes or endnotes, but Chicago also has an Author-Date system that uses parenthetical citations instead of notes.

Does Chicago style require a bibliography?

Notes & Bibliography usually includes a bibliography, but the exact requirement can depend on the assignment or publisher. Author-Date uses a reference list rather than a Notes & Bibliography-style bibliography.

Does Chicago use in-text citations?

Author-Date uses parenthetical in-text citations such as (Yu 2020, 45). Notes & Bibliography instead uses superscript note numbers in the text that point to footnotes or endnotes.

Is Chicago 18th edition the current edition?

Yes. The 18th edition of The Chicago Manual of Style was published in 2024.

Do Chicago 18 book citations need the city of publication?

For modern books, a place of publication is no longer normally required. Special cases, including older publications, can be treated differently.

How many authors do I list in Chicago 18?

In a bibliography or reference list, list up to six authors; for more than six, list the first three followed by et al. In a note or Author-Date text citation, list up to two authors; for more than two, use the first author followed by et al.

Should I use “ibid.” in Chicago footnotes?

Chicago 18 discusses ibid., but shortened citations are generally the clearer modern default for repeated references. See the Chicago Footnotes guide for the practical difference.

What should I do if my instructor’s example differs from Chicago 18?

Follow the requirements for your assignment. An instructor, department, dissertation office, journal, or publisher may specify a particular edition or house variation.

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Official Chicago sources

This guide was researched against current 18th-edition material from The Chicago Manual of Style.

• Chicago-Style Citation Quick Guide
• Notes and Bibliography: Sample Citations
• Author-Date: Sample Citations
• What’s New in the 18th Edition
• Chicago Resources for Students

ChicagoReferenceGenerator.com is an independent citation resource and is not affiliated with or endorsed by The University of Chicago or The University of Chicago Press.

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Continue with the guide you need

• Generate a citation with the Chicago Citation Generator
• Learn Chicago Notes & Bibliography
• Learn Chicago Author-Date
• Understand Chicago Footnotes
• Format a Chicago Bibliography
• Browse Chicago Citation Examples
• Review Chicago 18th Edition changes
• Cite a Book
• Cite a Journal Article
• Cite a Website
• Cite a Book Chapter