Citations tower · floor
Chicago style citation: two systems, not one
The first thing to know about chicago style citation is that there is no single Chicago style of citing. The Chicago Manual of Style publishes two systems, and they look nothing alike. Picking the one your department does not use is the error that costs marks, and no generator will catch it for you.
System one Chicago: sources are cited “in numbered footnotes or endnotes”, and the system is “preferred by
many working in the humanities, including literature, history, and the arts”. This is the one
with the little raised numbers. System two Chicago: sources are “briefly cited in the text, usually in parentheses, by author’s last name
and year of publication”, and it is “preferred by many in the sciences and social sciences”.
Closer to what APA looks like.Notes and bibliography
Author-date
So the honest first step is not “how do I format this” but “which of the two am I being marked against”. A history essay and a psychology paper can both be in Chicago and share almost nothing on the page.
Chicago’s own sample for a book by one author, notes-bibliography system, read 21 August 2026. Read down the three lines and the pattern is visible without any rule being quoted. The note keeps
the author’s name in normal order; the bibliography turns it round to put the family name first.
The note wraps the publication details in brackets; the bibliography separates them with full stops.
The note carries a page number; the bibliography does not. Nothing else moves.The same book, three times
Both systems are set out in the manual’s free Citation Quick Guide, which reflects the 18th edition. Chicago itself points beyond that guide: “For a more comprehensive overview of Chicago’s two systems of source citation, see chapter 13 of The Chicago Manual of Style. For many more examples organized by type of source, consult chapter 14.” Those chapters are in the manual, which is not free — the same gate that sits in front of MLA’s handbook.
The searches around this one show the same two-systems confusion. Chicago citation and chicago style format are people who have not yet been told there is a choice. Footnote citation is somebody already inside the first system, wanting the mechanics. Chicago manual of style is often someone looking for the book itself. And turabian is the student adaptation of the same manual, which is a floor of its own below.
One more thing worth saying before the floors, because it explains why this subject feels harder than it is. Almost nobody meets Chicago by choosing it. It arrives in a course handbook, usually as a single line, sometimes without naming which of the two systems is meant, and often alongside a sample essay that was formatted under an earlier edition. So the reader arriving here is rarely trying to learn a style — they are trying to match something they have been shown, without being able to see the rule behind it. Every floor below is written for that person: it shows the form first, says where the form comes from, and marks clearly the point at which the free guide stops and the book begins.
Where to start
Four ways in.
- “I do not know which system I need.”
- Start at choosing a system
- “Notes and bibliography.”
- Go to notes and bibliography
- “Author-date.”
- Go to author date
- “My course says Turabian.”
- That is turabian and editions
Choosing a system
The decision that comes before any formatting. Made once, at the start, it removes most of the work later.
Notes and bibliography
The footnote system: full note, shortened note, and the list at the end. The mechanics people search for most.
Author-date
The parenthetical system, and the reference list that goes with it. Nearer to APA than to the footnote version of Chicago.
Turabian and editions
The student edition, the current numbering, and the awkward fact that the full rules are behind a paywall.
What this tower will not do
It will not tell you which system to use. Your department does that, and any page that answers it for you is guessing about your course.
It will not quote a rule from an edition it has not read. The Quick Guide is free and current; much of what circulates online is a paraphrase of an older edition, and the difference is not always visible.
And it will not rank the citation tools yet. That needs the awkward sources — an archive box, a podcast, a translated work — put through each of them in both systems, with the mistakes published. What holds instead is simple: every sample on this page is Chicago’s own, from the free Citation Quick Guide.
Where this page got its facts
- The Chicago Manual of Style Online, Citation Quick Guide — the two systems and which disciplines use each — www.chicagomanualofstyle.org, read 21 August 2026.
- Citation Quick Guide, notes-bibliography samples — the full note, shortened note and bibliography entry quoted here — www.chicagomanualofstyle.org, read 21 August 2026.
Written by Alberto Gulotta
Founder and editor of AI Tools Primer, writing from Palermo, Italy. Thirty-five years of taking computers apart, starting with a Commodore 64 — the long version is on the about page.
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