Chicago Style Citation: Notes-Bibliography and Author-Date
Chicago is the style of choice in history, many arts and humanities fields and a lot of publishing. It looks different from APA and MLA because most of its citations live in footnotes, which keeps the text clean and lets you add comments along with sources.
This guide explains Chicago's two systems, shows examples of the most common source types and flags what changed in the latest edition. The examples use invented sources, so replace them with your own details.
Two systems in one manual
The Chicago Manual of Style describes two ways to cite.
| Notes-bibliography | Author-date | |
|---|---|---|
| In the text | A superscript number linking to a footnote or endnote | (Author Year, page) in parentheses |
| At the end | A bibliography | A reference list |
| Typical fields | History, literature, arts, religion | Sciences, social sciences |
| Reading feel | Clean text, citations in notes | Citations in the sentence |
You choose one system and use it consistently. This guide covers notes-bibliography in the most detail, since it is the one most students find new.
The edition question
The 18th edition of The Chicago Manual of Style was published in 2024, with the online edition appearing a little earlier. It is a major revision. Changes include capitalizing prepositions of five or more letters in titles, and no longer requiring the place of publication in book citations. Many courses and style guides still follow the 17th edition, so check which one yours uses. Follow the edition your instructor names. If none is named, be consistent and note which you used.
Notes-bibliography: footnotes
How it works
Put a superscript number after the sentence or clause containing a citation, and after the punctuation mark. The note with the same number appears at the bottom of the page (a footnote) or at the end of the paper (an endnote). Notes are numbered in order through the paper.
First citation of a source: full note
Use the full details the first time you cite a source.
Book:
- Rina Patel, Reading in the Digital Age (Harbor Press, 2020), 45.
Journal article:
- Jordan Lee and Rina Patel, "Practice and Comprehension in First-Year Students," Journal of College Learning 14, no. 2 (2021): 115, https://doi.org/10.0000/example.
Webpage:
- Marta Gomez, "How Students Read Online," Campus Study Guide, October 5, 2023, https://www.example.com/read-online.
In the notes, the author's name appears in normal order (first name first), and elements are separated by commas.
Later citations: shortened notes
For later citations, use a shortened note with the author's last name, a short title and the page.
- Patel, Reading in the Digital Age, 52.
When a note cites the same source as the one directly before it, repeat the shortened form. Some instructors allow "Ibid.", but recent editions of Chicago prefer the shortened note.
Notes-bibliography: the bibliography
At the end, list all sources in a bibliography, in alphabetical order by the first author's last name. Use a hanging indent. Here, authors appear last name first, and elements are separated by periods.
Book:
Patel, Rina. Reading in the Digital Age. Harbor Press, 2020.
Journal article:
Lee, Jordan, and Rina Patel. "Practice and Comprehension in First-Year Students." Journal of College Learning 14, no. 2 (2021): 112-29. https://doi.org/10.0000/example.
Webpage:
Gomez, Marta. "How Students Read Online." Campus Study Guide. October 5, 2023. https://www.example.com/read-online.
Notice the difference between a note (commas, first name first, specific page) and a bibliography entry (periods, last name first, whole page range).
Author-date system
If your instructor requires author-date, the format looks more like APA.
- In text: (Patel 2020, 45) or (Lee and Patel 2021, 115).
- Reference list entry: Patel, Rina. 2020. Reading in the Digital Age. Harbor Press.
In author-date, the year follows the author's name, and the page number comes after the year, separated by a comma. Use the same alphabetical order and hanging indent as in the bibliography.
Titles and capitalization
Chicago uses headline-style capitalization for titles in notes and bibliographies: capitalize the first and last words and all major words. Italicize titles of books, journals and other standalone works. Put titles of articles, chapters and webpages in quotation marks. Under the 18th edition, prepositions of five or more letters are capitalized in titles; under the 17th, they are lowercase. Follow your edition.
Quotations and notes
Short quotations go in quotation marks. Quotations of about five lines or more are set as block quotations, indented, without quotation marks. Notes can also hold short commentary, such as a point that does not fit in the text, along with the citation. Keep notes concise.
Citing common special cases
A few sources come up often enough to learn in advance.
- Several authors. In a note, list up to three authors, and for four or more give the first author followed by "et al." Check your edition and your instructor's preference for the bibliography.
- Editor or translator. Add "ed." or "trans." after the name, and give the original author first.
- Page ranges in notes. Cite the specific page the idea comes from, not the whole range of the article.
- Online sources. Give the URL or DOI at the end, and an access date only if the source has no clear publication date.
- Interviews and personal communication. These usually appear only in notes, not in the bibliography, because readers cannot retrieve them.
When a source does not fit a pattern, copy the closest example in the manual and keep the same order of elements.
Using notes well
Chicago notes are not only for citations. A good note can add a brief clarification, point to related reading or acknowledge a disagreement among scholars without breaking the flow of your argument. Keep notes short, usually one to three sentences, and avoid turning them into a second essay beneath the first. If a note is long enough to need its own paragraph, the material probably belongs in the text.
Formatting a Chicago paper
Many instructors ask for 1-inch margins, 12-point font, double-spaced text, single-spaced notes and bibliography entries with a blank line between entries, and page numbers. A title page is usual, with the title, your name, the course and the date. If the assignment gives different instructions, follow them.
Chicago compared with other styles
| Feature | Chicago notes | APA 7 | MLA 9 |
|---|---|---|---|
| Where citations go | Footnotes or endnotes | In the text | In the text |
| Emphasis | Source details and commentary | Date | Author and page |
| Typical fields | History, arts, humanities | Social sciences, education, nursing | Literature, languages |
| End list | Bibliography | References | Works Cited |
If you are choosing between the two most common in-text styles, see our guide to MLA vs APA, and for the difference between footnotes and endnotes, see footnotes vs endnotes.
Common Chicago mistakes
- Using the bibliography format in a note, or the note format in the bibliography.
- Repeating the full note every time instead of a shortened one.
- Putting the note number before the punctuation.
- Forgetting the bibliography in notes-bibliography papers.
- Mixing edition rules within one paper.
- Numbering notes incorrectly or restarting numbers by mistake.
- Using a citation generator and not checking the output.
Our citation generator can help you start an entry. For notes and a bibliography that must be exactly right, formatting help from an editor can check a graduate history or humanities draft.
A quick Chicago checklist
- Which system and edition does my instructor want?
- Is the superscript number after the punctuation?
- Is the first note full, and later notes shortened?
- Does the bibliography include every cited source, alphabetically?
- Are titles capitalized and styled consistently?
- Are note and bibliography formats not mixed up?
Final thoughts
Chicago's reputation for difficulty comes mostly from the notes. Once you see that a note and a bibliography entry hold the same information in two arrangements, the system becomes manageable. Pick the right edition and system, give each source a full first note, and keep your bibliography tidy.
Frequently asked questions
What is Chicago style?
Chicago style comes from The Chicago Manual of Style, published by the University of Chicago Press. It offers two systems: notes-bibliography, which uses footnotes or endnotes plus a bibliography, and author-date, which uses in-text citations plus a reference list.
Which Chicago system should I use?
Notes-bibliography is common in history, the arts and many humanities. Author-date is common in the sciences and social sciences. Use the one your instructor names. If they do not say, ask.
What is the difference between footnotes and endnotes?
Footnotes appear at the bottom of the page where the citation is made. Endnotes are collected at the end of the paper or chapter. Both use superscript numbers in the text, and your instructor may prefer one.
Which edition of Chicago should I follow?
The 18th edition was published in 2024, but many courses still follow the 17th. Check your syllabus or ask your instructor, since some details, such as title capitalization and place of publication, changed.
Do I still use ibid. in Chicago?
Recent editions discourage ibid. in favor of shortened notes. Some instructors still accept it, so check your course guidance.