Chicago Style Format Guide (With Examples and a Sample Paper)

I have read a lot of good history papers that lost a grade step in the last three pages. Not because the argument fell apart, but because the footnotes ran on periods where they should have run on commas, or the bibliography listed authors first name first, or the paper mixed footnotes and parenthetical citations as if they were interchangeable. Citation formatting is the cheapest mark on the rubric to secure and the most common one to give away.

This guide covers Chicago style the way I teach it in a seminar: two systems, three source types, one table you can keep open while you write. Everything below matches the 18th edition of The Chicago Manual of Style, published in 2024, and I flag the places where it differs from the 17th, since plenty of campus handouts have not caught up yet.

Which system, and who decides

Chicago is unusual among citation styles because it is really two styles under one name.

The first is notes-bibliography. You place a superscript number in the text, that number points to a footnote at the bottom of the page (or an endnote at the back), and a bibliography at the end lists every source alphabetically. This is the system of history, literature, art history, philosophy, religious studies, and most of the humanities. Its appeal is flexibility: a footnote can hold a comment, a translation, or a citation to a letter in an archive box, none of which fit neatly inside parentheses.

The second is author-date. You cite in the running text, in parentheses, with the author’s last name and the year, and a reference list at the end supplies the full details. Sociology, economics, some political science, and the natural sciences use it because it puts the date of the research in front of the reader every time a source is named.

The choice is rarely yours. The assignment sheet names the system, or the department’s style page does, or the journal you are imitating does. When none of those speaks, use the discipline as your guide, and when the discipline is ambiguous, ask. What you must not do is decide mid-draft, because converting a paper from one system to the other means rewriting every citation in it.

	Notes-bibliography	Author-date
In the text	superscript number	(Lepore 2018, 142)
Full details live in	footnotes or endnotes, plus a bibliography	a reference list only
Position of the year	near the end of the entry	right after the author’s name
Repeat citations	shortened note	same parenthetical again
Typical fields	history, literature, arts, philosophy	social sciences, sciences
Room for commentary	yes, inside the note	no

How the notes-bibliography format works

Suppose you quote a sentence from a book. The superscript number goes at the end of your sentence, after the closing punctuation. The first time you cite that book, the footnote gives full details:

1. Jill Lepore, These Truths: A History of the United States (W. W. Norton, 2018), 142.

First name first. Title in italics. Publisher and year in parentheses. Then the exact page you used. Commas hold the parts together, and the whole thing ends with a period.

If you have seen this format with a city in front of the publisher (New York: W. W. Norton, 2018), you were looking at the 17th edition. The 18th dropped the place of publication from book citations entirely. Either version will pass with most instructors this year, but the shorter one is now correct.

When you cite the same book again, you do not repeat all of that. You shorten it:

2. Lepore, These Truths, 209.

Last name, short title, page. The shortened form has been Chicago’s preferred choice for repeat citations since the 17th edition, ahead of the Latin abbreviation ibid., and the 18th keeps that preference. If your instructor still wants ibid., use it, but do not assume it.

At the end of the paper, the bibliography lists the same book once, alphabetized under the author’s last name:

Lepore, Jill. These Truths: A History of the United States. W. W. Norton, 2018.

Same source, and almost the same information, but every joint is different. The name flips to last name first so it can be alphabetized. The commas become periods. The parentheses disappear. The page number disappears too, because the bibliography entry describes the whole book, not the part you used. Students who understand that a footnote and a bibliography entry are two different sentences about the same object stop making the punctuation errors that come from treating one as a copy of the other.

Chicago style format examples: the three sources you will actually cite

Most undergraduate papers cite books, journal articles, and web pages, and almost nothing else. Learn these three in both forms and you have covered most of the ground. The examples below follow the 18th edition’s own citation guide; the article and web page are the ones the Manual itself uses, so you can check them against the source.

Book

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

Shortened note: 2. Yu, Interior Chinatown, 48.

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

Journal article

Note: 3. Hyeyoung Kwon, “Inclusion Work: Children of Immigrants Claiming Membership in Everyday Life,” American Journal of Sociology 127, no. 6 (2022): 1842-43, https://doi.org/10.1086/720277.

Shortened note: 4. Kwon, “Inclusion Work,” 1851.

Bibliography: Kwon, Hyeyoung. “Inclusion Work: Children of Immigrants Claiming Membership in Everyday Life.” American Journal of Sociology 127, no. 6 (2022): 1818-59. https://doi.org/10.1086/720277.

The article title sits in quotation marks and the journal name in italics. The note cites the pages you used; the bibliography gives the article’s full page range. Include the DOI whenever the article has one. Chicago sets page ranges with a slightly longer dash than the plain hyphen shown here; your word processor will usually insert it for you, and no instructor I know has ever docked a mark for the hyphen.

Website

Note: 5. “About Yale: Yale Facts,” Yale University, accessed March 8, 2022, https://www.yale.edu/about-yale/yale-facts.

Bibliography: Yale University. “About Yale: Yale Facts.” Accessed March 8, 2022. https://www.yale.edu/about-yale/yale-facts.

Web pages often have no named author, in which case the organization that owns the site takes that slot in the bibliography. They also often have no publication date. When that happens, give the date you accessed the page instead. If the page does carry a date, use it and drop the access date, unless your instructor asks for both.

Author-date, briefly

The same three sources look like this in the second system. Notice the year moving forward to sit directly after the author, and the citation shrinking to a parenthetical:

Lepore, Jill. 2018. These Truths: A History of the United States. W. W. Norton.

In the text: (Lepore 2018, 142)

Kwon, Hyeyoung. 2022. “Inclusion Work: Children of Immigrants Claiming Membership in Everyday Life.” American Journal of Sociology 127 (6): 1818-59. https://doi.org/10.1086/720277.

In the text: (Kwon 2022, 1851)

Yale University. n.d. “About Yale: Yale Facts.” Accessed March 8, 2022. https://www.yale.edu/about-yale/yale-facts.

In the text: (Yale University, n.d.)

A few things worth knowing about the parenthetical. There is no comma between the author and the year. There is a comma before a page number. When a source has no date, write n.d. in the reference list and put a comma before it in the text, since otherwise it reads as part of the name. Two authors are joined with “and” (Binder and Kidder 2022); four or more are cut to the first author plus “et al.”

The reference list is alphabetized by last name, exactly like a bibliography, and it carries a hanging indent. The parenthetical citation and the reference entry must match on the first word, or the reader cannot find one from the other.

Footnote versus bibliography entry, side by side

Keep this table open while you format. Nearly every error I mark comes from swapping a rule in the left column for one in the right.

Feature	Footnote	Bibliography entry
Author’s name	First Last	Last, First
Separators between parts	commas	periods
Publication details	in parentheses	no parentheses
Page numbers	the page(s) you used	none for a book; full range for an article
Starts with	a number and a period	the author’s last name
Order	in the sequence you cite	alphabetical
Repeat citations	shortened form	listed once only

Sample paper page setup that instructors check

Chicago’s formatting rules for the page are less strict than its citation rules, and Turabian, the student manual built on Chicago, fills in the details most courses expect. The list below is what I check on the first page of a submission.

1. A readable 12 point font, double-spaced body text, one inch margins.
2. Footnotes single-spaced, with a blank line between notes.
3. The bibliography on its own page, titled Bibliography, single-spaced within entries and double-spaced between them, with a hanging indent of half an inch.
4. Page numbers in the header or footer, consistently placed; the title page carries none.
5. Superscript numbers placed after punctuation, never before it, and never repeated: each note gets a new number even when it cites a source you have used before.

The hanging indent trips up more people than it should. Set it in the paragraph settings of your word processor rather than pressing tab, because a tabbed indent breaks the moment an entry rewraps.

The mistakes that cost marks

Over a term I keep a tally of the citation errors I circle. The distribution barely changes from year to year.

Mixing the two systems is the worst of them, and the most avoidable. A paper with footnotes in the first half and parenthetical citations in the second reads as if two different people wrote it, and it tells the grader you did not read the assignment sheet. Second is the punctuation swap: bibliography entries written with commas, or footnotes written with periods and the name reversed. Third is the missing bibliography, usually from a student who assumed the footnotes were enough. Fourth is the full citation repeated in every note, which is not wrong in the strict sense but reads as padding and makes the notes twice as long as they need to be. Fifth is the invented format for an unusual source: a film, a podcast, a tweet, a court case, cited by analogy to a book because the writer did not want to look it up. The Manual has a rule for every one of those, and a librarian can find it in three minutes.

Then there is the citation manager. Zotero and its relatives are genuinely useful, and I recommend them, but they are only as good as the metadata they scrape. A record pulled from a publisher’s page often arrives with the title in the wrong case or the page range missing. The tool produces a draft. You proofread it against the examples above, one part at a time, before it goes in the paper.

Cite one source, check it against the table, move on.

When the Manual and your instructor disagree

They will, occasionally. A professor who learned Chicago on the 15th edition may want the city of publication, or ibid., or access dates on every web source. The rubric wins. The Manual is a reference for when the assignment is silent, not an authority you can cite against the person grading you. Consistency within a single paper matters far more than fidelity to any edition, and every instructor I know would rather see one system applied cleanly than two applied correctly in patches.

For the research process that comes before citation, our guide to writing a research paper covers source selection and note-taking, and the guide to writing plagiarism-free explains what needs a citation in the first place. This one only handles the format, but the format is where the easy marks are.