Chicago referencing is widely used in history, the arts and some social sciences, and it is unusual in offering two different systems. This UK guide explains both, shows you how footnotes and author–date citations work, gives clear examples for common sources, and points out the mistakes that most often cost marks.
The Two Chicago Systems Explained
Chicago style comes in two forms. The notes-bibliography system uses numbered footnotes or endnotes plus a bibliography, and is favoured in history and the humanities. The author-date system uses in-text citations with a reference list, much like Harvard, and is common in the sciences and social sciences. Your department will specify which to use, so check your handbook before you start — never mix the two in one piece of work.
Chicago Notes-Bibliography: Footnotes and Bibliography
In the notes system, a superscript number in your text points to a footnote giving full source details the first time, and a shortened form thereafter. A first footnote for a book reads: Author First Last, Title (Place: Publisher, Year), page. The matching bibliography entry inverts the author’s name and ends with a full stop rather than page-specific detail: Last, First. Title. Place: Publisher, Year. Footnotes use commas; bibliography entries use full stops.
Chicago Author-Date: In-Text and Reference List
The author-date system places the author and year in brackets in your text, for example (Smith 2024, 15), with the page number after a comma. The reference-list entry reads: Last, First. Year. Title. Place: Publisher. This system is quicker to read and is preferred where you cite many sources, which is why the sciences tend to favour it.
Chicago Reference Examples
Here are quick author-date reference-list templates for the sources students cite most. Book: Last, First. Year. Title. Place: Publisher. Journal article: Last, First. Year. “Article Title.” Journal Name Volume (Issue): pages. Website: Last, First. Year. “Page Title.” Site Name. Month Day, Year. URL. Adjust the punctuation if your department uses the notes-bibliography system instead.
Common Chicago Referencing Mistakes
The usual errors are mixing the two systems, using commas where full stops belong (and vice versa), forgetting to shorten repeated footnotes, and omitting page numbers in footnote citations. Students also frequently misplace the year — remember it sits differently in each system. Keeping a style guide open as you write, and being ruthlessly consistent, is the simplest way to avoid losing marks on presentation.
Frequently Asked Questions
Which Chicago system should I use?
It depends on your subject. History and the humanities usually use notes-bibliography, while the sciences and social sciences often use author-date. Always confirm with your module handbook or tutor.
Is Chicago style the same as Turabian?
They are closely related. Turabian is a student-focused version of Chicago style with minor simplifications, so if your course asks for Turabian, the principles in this guide still apply.
Do I need both footnotes and a bibliography?
In the notes-bibliography system, yes — footnotes cite sources as you go and the bibliography lists them all at the end. The author-date system uses in-text citations with a reference list instead.
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