EdCitation publishes this guide with its view on when to use Chicago author-date and when a paper needs Chicago's other system, notes and bibliography. The view is ours. Each fact under it comes from reading, on 23 September 2026, the Chicago Manual of Style Online's free pages, three university departments' pages and one journal's style sheet. The full Manual is sold by subscription, so a rule found only there is left out.
The short version: author-date suits social science, business and science papers that argue from dated books and articles. Notes and bibliography suits history and the humanities, where sources are letters, manuscripts and documents without a clear author or year. A brief that names one system settles it, and EdCitation's free Check your paper lifts the style a brief names into a checklist beside its word limit and required sections.
One fact first, because it decides what a tool can do for you. EdCitation's Chicago citation generator builds Chicago 18 author-date only, never notes and bibliography, so a course that wants footnotes means setting them out from the Chicago Manual or Turabian. The rules of author-date are in the Chicago author-date referencing guide.
What are Chicago's two systems, and what is each for?
Chicago has two systems, and Chicago itself says which fields lean to each. The University of Chicago Press (n.d.-a) sets them out on its citation quick guide:
- Notes and bibliography cites sources in numbered footnotes or endnotes, usually with a separate bibliography. The press calls it "Chicago's oldest and most flexible" system, the one that handles unusual sources author-date struggles with, and says it is preferred by many in the humanities, literature, history and the arts among them.
- Author-date cites a source in the text, usually in parentheses, by surname and year, each leading to an entry in a reference list. Because it names researchers while "emphasizing the date of each source", many in the sciences and social sciences prefer it.
The two share one style for names, titles and the other parts of a citation; what differs is the note against the parenthesis. Most authors, the page adds, follow their field or publisher, and students should check with their instructor.
What the Turabian pages add
Turabian's A Manual for Writers comes from the same press, and its quick guide sits on the Chicago Manual's site. The University of Chicago Press (n.d.-d) says its two systems are "sometimes referred to as Chicago-style citations" because they match the Manual's, calls notes popular in the humanities and author-date more common in the physical, natural and social sciences, and sends an unsure student to the instructor. So a brief that says "Turabian" has not chosen a system either.
When should I use Chicago author-date?
Use it when the brief or the journal names it. Where the choice is open, these are the papers it suits in our view.
Dated sources in the social sciences, business and the sciences
A sociology essay, a politics paper or a market analysis argues from studies and reports whose age matters. Author-date keeps the year inside the sentence, the reason Chicago gives for the sciences' preference, so a reader sees which of two findings is newer without turning to the list. It works best when every source is a book or article with a printed author and year: then a parenthesis does the whole job and nothing needs a note at the foot of the page.
Economic history, where a journal sets it
Some history is written in author-date. Cambridge University Press (2019) publishes the Journal of Economic History's style sheet, which asks for the "Harvard" or author-date system in the text and footnotes, as in (Persson 1993, p. 105), and a reference list that generally follows the bibliography style of the Manual's 14th edition, of 1993.
That journal's Chicago is its own. It writes "p." before the page, which Chicago's own samples never do: University of Chicago Press (n.d.-e) examples read (Yu 2020, 45). And it ordinarily cites a single archive item only in a footnote, listing the archive itself when the notes cite it more than once. Even an author-date journal sends archive material to a note. For a manuscript, the journal's sheet outranks this guide.
We tried to read a second example, the instructions for authors of a journal on the history of the philosophy of science; the page sat behind a bot check, so we name none.
When do I need Chicago notes and bibliography instead?
When the course asks for footnotes, and, in our view, whenever the sources are ones that a name and a year cannot pin down.
Archives, manuscripts and undated sources
A letter in a family collection has a writer and a date, but a reader who wants it also needs the folder, the box, the collection and the archive. The history department at Hanover College (2026) lists those parts for a manuscript note, from the single item out to the archive, and tells students to follow the archivist's advice when in doubt. A footnote carries all of that beside the claim; a parenthesis carries a surname and a year.
The 18th edition touches the same ground: University of Chicago Press (n.d.-b) guidance says an unpublished manuscript that others cannot consult may be mentioned in the text or a note but is not usually listed. Author-date can cite such sources, but each needs a workaround. Notes take them in their stride, as Chicago's own description of the system says.
Courses that set footnotes
Three departments read today set notes and bibliography in their own words.
- History, Hanover College. Its footnote guide, updated for the 18th edition, says leading publishers of historical scholarship, naming the American Historical Review and the Journal of American History, require Chicago footnotes. That is the department's statement; we did not read those journals' pages.
- Art history, UA Little Rock. The School of Art and Design calls Chicago the "department standard", required in every art history course, with footnotes or endnotes and a bibliography (University of Arkansas at Little Rock, 2024). Its examples still give a place of publication, which the 18th edition no longer asks for.
- Religious studies, UNC Charlotte. The University of North Carolina at Charlotte (2025) says every professor in the department requires its majors and graduate students to follow Turabian, with "only the footnote and bibliography format" and a list headed Bibliography, not Works Cited. It names Turabian's 7th edition, of 2007, and describes content footnotes: asides that sit beside the argument, not in it.
We read no classics or theology department's page today, so we say nothing about those subjects.
When does another style serve better than either Chicago?
When the course names it, and, in our view, in four kinds of work.
- Research on people, where the course names APA or Harvard. Both are author-date styles too. See when to use APA style and when to use Harvard referencing.
- Close reading. An essay on the wording of a poem needs the line or page more than the year, which is MLA's strength (when to use MLA style).
- Engineering and computing. IEEE's bracketed numbers suit prose full of equations (when to use IEEE style).
- Medicine. Vancouver is the numbered style of the medical journals (Vancouver referencing guide).
Which Chicago, or which style, suits which situation?
Our summary. A brief or journal that names a style overrides every row.
| Situation | What suits it | Why, in short | Built by EdCitation? |
|---|---|---|---|
| Sociology or business paper, brief says Chicago | Chicago author-date | The year stays in the sentence | Yes |
| Economic history journal article | The journal's own sheet | Its house rules outrank the Manual | References yes, footnotes no |
| History essay from letters and record offices | Chicago notes and bibliography | Box and folder fit in a note | No |
| Art history or religious studies, footnotes set | Notes and bibliography | The department requires it | No |
| Brief says only "Turabian" | Ask which system | Turabian has both | Author-date only |
| Brief says only "Chicago" | The course guide's examples | A numbered note or a parenthesis settles it | Author-date only; Check your paper reads the brief |
| Psychology or nursing, APA named | APA 7 | Named by the course | Yes |
| Poem or novel read closely | MLA 9 | Points to the line or page | Yes |
What did the 18th edition change that touches the choice?
Nothing about which fields should use which system: the list of changes names none (University of Chicago Press, n.d.-b). What it changed brings the two systems closer.
Changes that reach both systems
- Et al. A note and an author-date citation both give up to two authors, then the first author and "et al."; a bibliography or reference list gives up to six, or the first three and "et al." (13.23, 13.107).
- Books and chapters. No place of publication is required for books (14.30), and no chapter page range in the list (14.8).
- Repeated names. Chicago now prefers repeating an author's name to a 3-em dash (13.72, 13.113).
Changes for one system only
- Notes. A shortened citation used instead of "ibid." may give author and title, author alone or title alone (13.37). Elements named in the text can often be dropped from a footnote but not usually from an endnote (13.47).
- Author-date. An entry with a month and day, as for a newspaper article, need not repeat the year with them (14.89).
Department pages lag. Hanover's is updated for the 18th edition; UA Little Rock's keeps the place of publication and UNC Charlotte's names a Turabian from 2007. Check which edition your course marks against.
How do I work out which Chicago my brief means?
Take these steps in order; the first one that settles it is your answer.
- Read the exact words. "Author-date", "parenthetical" or "reference list" mean author-date. "Footnotes", "endnotes", "notes and bibliography" or a Bibliography heading mean notes. On a long brief, EdCitation's Check your paper finds the style line for you and lists it with the other requirements.
- If it says only "Chicago", open the course or department guide and look at its examples: a numbered note means notes and bibliography, a surname and year in parentheses mean author-date.
- If it says "Turabian", ask which system. Turabian has both, and one department's notes-only rule is not yours.
- Check the edition. The Manual is in its 18th edition and the Turabian site covers its 9th.
- Writing for a journal? Use its own sheet, which may differ from the Manual.
- Still unsure? Ask the instructor, as both of Chicago's quick guides advise, and meanwhile record every source in full, with pages, so either system can be set.
- Keep one system throughout, from your first citation to the last entry in the list.
How does EdCitation help with Chicago author-date?
EdCitation is the best tool for a Chicago author-date reference, because Cite a source builds each entry out of what the publisher recorded, never out of guesswork, which is more than any chatbot can say. Enter the source's DOI, PubMed ID, ISBN or title and the Chicago 18 author-date entry follows, with a retraction screen, free and without an account. The record matters because Chicago's rules turn on facts a record holds: where an article's online year and its issue's year differ, Cite a source gives the issue's, as the University of Chicago Press (n.d.-c) Q&A directs. An article number goes where the pages would, as in "13 (1): 14045". Titles keep the capitals the publisher deposited, so one deposited in sentence case needs Chicago's title case put back by hand.
The same record gives every style: the style menu re-sets one source in any of the six styles (APA 7, MLA 9, Harvard, IEEE and Vancouver as well as Chicago) without a new search. With a free account, the dashboard keeps a reference list whose own style menu re-sets every entry, so a tutor who answers "APA, not Chicago" costs a menu choice, not a retyped list. The Chicago page states the limit: "If your course asks for footnotes, it wants Chicago notes-bibliography instead."
Verify references, also free, checks the finished list against the same records. Its verdicts are verified, "check this" and not found, with retractions flagged; a reference that could not be checked is shown that way and is not counted as not found. Upload the whole paper and each (Author Year) is matched to an entry, and each entry to the text.
Paying $8 a month for Pro adds References from a file, plagiarism and AI checks, and Mechanics QA, though that last one tests a paper only against the APA 7 student format, never Chicago's. Max, at $24 a month, adds Theoretics QA, which judges a paper against its assignment's own instructions and never rewrites it, and the Library. Both are on the pricing page.
What it does not do: it builds no notes and bibliography and no footnotes, so a footnoted paper is set out by hand from the Chicago Manual or Turabian. It does not choose your style; the brief does. And no part of your paper is ever written by EdCitation.
Quick questions
Is Turabian the same as Chicago?
Turabian's citation systems are Chicago's, and it offers both notes and author-date. A brief that says only "Turabian" still leaves the system to be chosen.
Can I write a history essay in Chicago author-date?
Yes, if the course allows it; the Journal of Economic History publishes economic history in author-date. The history department guide read for this article sets footnotes, so the brief decides.
Does EdCitation make Chicago footnotes?
No. EdCitation's free Chicago citation generator builds Chicago 18 author-date references only, so footnotes are set out from the Chicago Manual or Turabian.
Did the 18th edition change which Chicago system to use?
No. Chicago's list of 18th edition changes says nothing about which fields use which system, and it gave notes and author-date citations the same "et al." rule.
What if my brief just says "Chicago"?
Look at the examples in the course guide: numbered notes mean notes and bibliography, a surname and year in parentheses mean author-date. If there are none, ask the instructor, as Chicago's quick guide advises; EdCitation's free Check your paper puts any style the brief names into its checklist.
References
- Cambridge University Press. (2019, July). The Journal of Economic History style sheet. Cambridge Core. https://www.cambridge.org/core/journals/journal-of-economic-history/information/instructions-contributors/style-sheet
- Hanover College. (2026). Style guide for Chicago Manual footnotes. History Department. https://history.hanover.edu/footnotes.php
- University of Arkansas at Little Rock. (2024, December 3). Guidelines for writing art history research papers. School of Art and Design. https://ualr.edu/art/art-history-resources/guidelines-for-writing-art-history-research-papers/
- University of Chicago Press. (n.d.-a). Chicago-style citation quick guide. The Chicago Manual of Style Online. https://www.chicagomanualofstyle.org/tools_citationguide.html
- University of Chicago Press. (n.d.-b). What's new in the 18th edition. The Chicago Manual of Style Online. https://www.chicagomanualofstyle.org/help-tools/what-s-new.html
- University of Chicago Press. (n.d.-c). Citation, documentation of sources (Q&A No. 387). The Chicago Manual of Style Online. https://www.chicagomanualofstyle.org/qanda/data/faq/topics/Documentation/faq0387.html
- University of Chicago Press. (n.d.-d). Turabian citation quick guide. The Chicago Manual of Style Online. https://www.chicagomanualofstyle.org/turabian/citation-guide.html
- University of Chicago Press. (n.d.-e). Author-date: Sample citations. The Chicago Manual of Style Online. https://www.chicagomanualofstyle.org/tools_citationguide/citation-guide-2.html
- University of North Carolina at Charlotte. (2025, May 6). Formats for footnotes and bibliography. Department of Religious Studies. https://religiousstudies.charlotte.edu/formats-footnotes-and-bibliography/