"Chicago style" isn't one format — it's two, and the Chicago Manual of Style leaves it up to your instructor or field to say which one applies. Notes-bibliography uses footnotes; author-date uses in-text parentheses. On top of that, the Manual's 18th edition, published in 2024, changed several of the rules a generator needs to get right. Here's how both systems work, and what's actually different now.
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Notes-bibliography is the version built around footnotes or endnotes, most common in history, literature, and the arts. The first time you cite a source, you write a full note with complete publication details — for example: Virginia Woolf, "Modern Fiction," in Selected Essays, ed. David Bradshaw (Oxford: Oxford University Press, 2008), 11. Every citation after that first one gets a short note instead — just the author's last name, a shortened title, and the page: Woolf, "Modern Fiction," 11.
Author-date is the version used more in the sciences and social sciences, and it works like APA: a parenthetical author-and-year in the text, matched to a full reference list entry at the end. The two systems aren't mixed within one paper — you (or your instructor, or your target journal) pick one and use it consistently throughout.
The Chicago Manual of Style's 18th edition, published in 2024, made several concrete changes that affect how a citation gets formatted, not just style advice. For notes and in-text citations, up to two authors are now named before switching to the first author plus "et al."; for bibliography or reference-list entries, that cutoff moved to six authors before switching to "et al." for the rest. Under the older 17th edition, that cutoff was set differently, so a citation formatted under the old rule can look wrong under the new one.
A handful of other 18th-edition changes worth knowing: a place of publication is no longer required for books published since 1900, page ranges are no longer mandatory in bibliography entries for individual book chapters, DOIs must now be formatted as a full URL (https://doi.org/10.1086/718629) rather than the older "doi:" prefix, and the month or season can usually be dropped from journal-article citations. The 18th edition also added new guidance for citing AI-generated content and chatbot output directly, which wasn't addressed in earlier editions.
A citation generator handles the mechanical, easy-to-get-wrong parts reliably: full note vs. short note formatting, correct punctuation and italics, and applying the right author cutoff for whichever edition you're citing under. StudyPilot's citation generator supports Chicago directly, alongside APA, MLA, Harvard, IEEE, and Vancouver.
What it can't do for you is pick the right system in the first place — notes-bibliography or author-date — since that depends on your instructor's or field's convention, not on the source itself. It's also worth confirming which edition your course or publisher expects: a paper citing sources under 17th-edition author-cutoff rules when your instructor expects the 18th edition (or vice versa) is a real, easy-to-miss mismatch.
Enter your source details and get a properly formatted Chicago citation — notes-bibliography or author-date, your call.
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