Chicago citation style is the documentation system published in The Chicago Manual of Style, and it comes in two forms. The notes-bibliography system uses numbered footnotes or endnotes matched to a full bibliography, while the author-date system uses short in-text parentheses matched to an alphabetical reference list. Historians, literature scholars, and art critics generally use notes-bibliography, while researchers in the physical, life, and social sciences generally use author-date. This guide covers paper formatting, both citation systems with worked examples, bibliography entries for the most common source types, and the mistakes that cost students the most points.
What Is Chicago Style?
The style is maintained by the University of Chicago Press and covers everything from manuscript formatting to grammar and documentation. The University of Chicago Press released the 18th edition of the manual, and it is the current standard both citation systems in this guide follow. It is sometimes confused with Turabian style, a simplified version built for student papers, which is covered further down this guide.
| System | How It Works |
|---|---|
| Notes-Bibliography | Sources are cited in numbered footnotes or endnotes, each matched to a full bibliography entry at the end of the paper. Preferred in history, literature, and the arts. |
| Author-Date | Sources are cited in short parentheses in the text, each matched to an alphabetical reference list entry. Preferred in the physical, life, and social sciences. |
How to Format a Chicago-Style Paper
Both systems share the same underlying paper format. Use the table below as a quick reference before you start writing.
| Element | Rule |
|---|---|
| Font and spacing | 12-point Times New Roman (or similar), double-spaced throughout, including block quotes and notes. |
| Margins | 1-inch margins on all sides. |
| Page numbers | Top right corner, starting on the first page of text (the title page is usually unnumbered). |
| Title page | Full title centered about a third of the way down, followed by your name, course, instructor, and date, each on its own line. |
| Headings | Bold or italic, title case, with consistent spacing above each level used. |
| Block quotes | Set off quotes of five or more lines as an indented block, without quotation marks. |
The Purdue OWL’s Chicago Manual of Style overview is a useful second reference for edge cases like appendices and tables of contents.
Chicago In-Text Citations: Notes-Bibliography System
In the notes-bibliography system, every borrowed idea, quote, or paraphrased fact gets a superscript number placed after the punctuation. That number corresponds to a footnote at the bottom of the page or an endnote at the end of the paper. The first note for a source is written in full. A shortened note (author’s last name, short title, page number) is used for repeat citations of the same source.
Footnote (first citation):
1. Jane Smith, Writing History (Chicago: University of Chicago Press, 2025), 42.
Bibliography entry:
Smith, Jane. Writing History. Chicago: University of Chicago Press, 2025.
Follow our guides on introducing quotations and paraphrasing if you are not sure whether a sentence needs a note at all. Notice the footnote uses the author’s first name first and a page number, while the bibliography entry inverts the name for alphabetizing and drops the page number. Titles of books and journals are italicized, and article titles go in quotation marks.
Chicago In-Text Citations: Author-Date System
In the author date system (sometimes written with a hyphen as “author-date”), you cite the source in parentheses right after the borrowed material, using the author’s last name and the year of publication. A page number is added for direct quotes, and the full source information sits in the reference list, not the URL bar of your citation manager. Each in-text citation points to a full entry in the reference list at the end of the paper.
In-text: (Smith 2025, 42)
Reference list: Smith, Jane. 2025. Writing History. Chicago: University of Chicago Press.
The reference list is alphabetized the same way as a notes-bibliography list, but the publication year moves right after the author’s name instead of sitting at the end of the entry.
Chicago Bibliography Examples by Source Type
The exact entry format changes slightly by source type, and each row below reuses the same source cited three ways so you can see how the punctuation and word order shift. The table below shows a bibliography (notes system) entry and a reference list (author-date) entry side by side for the four source types students cite most often.
| Source Type | Bibliography (Notes System) | Reference List (Author-Date) |
|---|---|---|
| Book | Smith, Jane. Writing History. Chicago: University of Chicago Press, 2025. | Smith, Jane. 2025. Writing History. Chicago: University of Chicago Press. |
| Journal article | Lee, Kim. “Rethinking Archives.” Journal of History 12, no. 3 (2025): 200-15. | Lee, Kim. 2025. “Rethinking Archives.” Journal of History 12 (3): 200-15. |
| Website | “Chicago Style Guide.” Purdue OWL. Accessed May 3, 2026. URL: https://owl.purdue.edu. | Purdue OWL. 2026. “Chicago Style Guide.” Accessed May 3, 2026. URL: https://owl.purdue.edu. |
| Newspaper article | Diaz, Mark. “City Council Votes on Budget.” Chicago Tribune, March 4, 2026. | Diaz, Mark. 2026. “City Council Votes on Budget.” Chicago Tribune, March 4. |
For source-specific rules on citing books and journal articles, see our guides on how to cite a book and how to cite a journal article.
Online sources and print articles follow slightly different rules too, and citation managers won’t always fill in every required field for you. Our guides on how to cite a website and how to cite a newspaper article cover the source-specific details this table leaves out, including how to handle missing authors and access dates.
Chicago Style vs. Turabian, MLA, and APA
This is not the only documentation system you will run into. Turabian style, formally titled A Manual for Writers of Research Papers, Theses, and Dissertations, is based directly on Chicago style but trims some of the publishing-industry conventions that do not apply to student papers, such as rules for printers and typesetters. If your instructor says “Turabian,” you can follow this guide’s citation formats with very few adjustments.
Not sure which style your assignment calls for? Compare all three side by side in our full citation styles guide, or jump straight to the MLA style guide or APA style guide if your instructor named one of those instead.
If you would rather generate citations automatically once you know your style, EssayReply’s Chicago citation generator builds both notes-bibliography and author-date entries from a source URL or ISBN.
When to Use Chicago Style
Your instructor or publisher will usually specify a style, but if you are choosing on your own, these fields typically default to Chicago:
- History
- Literature
- Art history
- Classics
- Religious studies
- Philosophy
- Social sciences (author-date)
- Physical and life sciences (author-date)
Common Chicago Citation Mistakes to Avoid
| Mistake | Fix |
|---|---|
| Mixing systems | Pick either notes-bibliography or author-date for the whole paper. Never mix footnotes with parenthetical citations. |
| Placing the superscript before punctuation | The footnote number always comes after the period, comma, or closing quotation mark, not before it. |
| Forgetting the shortened note | After the first full footnote, later citations of the same source use a shortened form, not the full citation again. |
| Wrong name order in the bibliography | Bibliography and reference list entries invert the first author’s name for alphabetizing. Footnotes and in-text citations do not. |
| Skipping the access date online | Chicago style asks for an access date on web sources without a clear publication date. |
Frequently Asked Questions About Chicago Style
Is Chicago style the same as Turabian style?
They are closely related but not identical. Turabian is a simplified version of Chicago style designed for student papers, dropping some publishing-specific rules that do not apply outside of print production.
Should I use notes-bibliography or author-date?
Check your assignment sheet first. Without instructions, use notes-bibliography for history, literature, and the arts, and author-date for the social, physical, and life sciences.
Do I need both footnotes and a bibliography?
In the notes-bibliography system, yes. Many instructors accept notes alone for shorter papers, but a full bibliography is standard for research papers and theses.
How do I cite a source with no author?
Start the entry with the title instead of an author name, and alphabetize it by the first significant word of the title in the bibliography or reference list.
What edition of the Chicago Manual of Style should I use?
Use the current 18th edition unless your instructor or publisher specifically asks for an older one. The core citation rules covered in this guide have stayed consistent across recent editions.
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Terry is a Chicago-based writer and editor who creates practical, student-friendly guides on essay writing, research, and citation styles (APA, MLA, and Chicago). He’s spent 15+ years editing educational content and building clear examples that help readers apply rules without guessing. When he’s not revising drafts, he’s usually turning messy notes into clean outlines and hunting down the one detail everyone skips.