Chicago style has two citation systems, and the first step is knowing which one you are using. The notes and bibliography system uses numbered footnotes or endnotes alongside a bibliography. The author-date system uses short in-text citations alongside a reference list. This guide covers notes and bibliography, the version used most in history, literature and the arts. The citation generator builds either format for you, but it helps to understand the structure first.
The two Chicago systems and who uses them
Both systems come from the same Chicago Manual of Style, and they cite the same sources with the same details. They differ only in how the citation appears in your text.
- Notes and bibliography. Each reference gets a numbered footnote or endnote, and full source details sit at the bottom of the page or in an endnotes list. A bibliography at the end lists every source. History, art history, literature, theology and similar fields use this system.
- Author-date. A short citation in parentheses, such as (Tufte 2001, 92), appears in the running text. Full details go in a reference list at the end. The sciences and many social sciences use this system.
If you are not told which to use, notes and bibliography is the usual default for humanities coursework. The rest of this guide stays with it.
Bibliography entry for a book
A bibliography lists every source once, alphabetised by author surname, with a hanging indent. The basic book format is:
Last, First. Title. City: Publisher, Year.
A worked example:
Tufte, Edward R. The Visual Display of Quantitative Information. Cheshire, CT: Graphics Press, 2001.
The author name is inverted (surname first) so the list sorts alphabetically. The title is in italics, the place of publication comes before the publisher, and the entry ends with the year and a full stop. For two or more authors, only the first name is inverted: Last, First, and First Last.
Footnote or endnote format
A note is the citation tied to a specific number in your text. The first time you cite a source, give the full note. The format reorders the same details and uses commas instead of full stops:
First Last, Title (City: Publisher, Year), page.
The same book as a first full note:
- Edward R. Tufte, The Visual Display of Quantitative Information (Cheshire, CT: Graphics Press, 2001), 92.
The differences from the bibliography entry are worth noting: the author name is in normal order, the publication facts sit in parentheses, the separators are commas, and the note points to a specific page.
Shortened notes for repeat citations
You only give the full note once. Every later citation of the same source uses a shortened note: the author surname, a short form of the title, and the page.
- Tufte, Visual Display, 92.
The short title keeps the first few key words and stays in italics for a book. This is the current Chicago practice for repeat references. The older ibid. form for consecutive citations of the same source is no longer recommended, so use a shortened note even when two notes in a row cite the same work.
Citing a website
Online sources follow the same logic, with a URL and an access or publication date when no clear date is given. The bibliography entry:
Author Last, First. “Page Title.” Site Name. Month Day, Year. URL.
A note for the same page:
- First Last, “Page Title,” Site Name, Month Day, Year, URL.
If the page has no listed author, start with the page title. If it has no date, add an access date before the URL, written as “accessed Month Day, Year.” Keep the URL as the last element.
Putting it together
The pattern repeats across source types: the bibliography inverts the author name and separates details with full stops, the first note uses normal name order with commas and a page number, and repeat citations shrink to a shortened note. Get those three forms right and most of Chicago falls into place.
To compare this against other styles, see APA vs MLA vs Chicago, or read the Harvard referencing guide for an author-date approach. When you are ready, the Chicago citation tool formats notes and bibliography entries for you.