Last updated: March 2026
Notes-Bibliography vs Author-Date Systems
The Chicago Manual of Style offers two distinct citation systems, each suited to different academic disciplines. The Notes-Bibliography system uses superscript numbers in the text that correspond to footnotes or endnotes, with a comprehensive bibliography at the end. This system is preferred in history, the arts, and many humanities fields because it allows for discursive notes that add context beyond simple source attribution.
The Author-Date system uses parenthetical in-text citations similar to APA, with a reference list at the end. This system is common in the sciences and social sciences. Our generator produces citations in both the Author-Date reference list format and the bibliography format, so you can use the output for either system. The key structural difference is that the Author-Date reference list entry places the year immediately after the author name.
Frequently Asked Questions
What is Chicago citation style?
The Chicago Manual of Style (CMOS) 17th edition is a comprehensive style guide used primarily in history, the arts, and some social sciences. It offers two citation systems: Notes-Bibliography (footnotes with a bibliography) and Author-Date (parenthetical citations with a reference list). Our generator uses the Author-Date system.
What is the difference between Notes-Bibliography and Author-Date?
Notes-Bibliography uses superscript numbers in the text that correspond to footnotes at the bottom of the page, plus a bibliography at the end. Author-Date uses parenthetical citations like (Smith 2024) with a reference list. Notes-Bibliography is common in humanities; Author-Date is used in sciences and social sciences.
How do I cite a website in Chicago style?
In Chicago Author-Date: Author Last, First. "Title of Page." Site Name. Month Day, Year. URL. In Notes-Bibliography, the footnote version inverts: First Last, "Title of Page," Site Name, Month Day, Year, URL.
Does Chicago style require a bibliography?
In Notes-Bibliography style, a bibliography is expected but sometimes optional if footnotes contain complete information. In Author-Date style, a reference list is always required. The bibliography lists all sources alphabetically by author last name.
How do I format footnotes in Chicago style?
Footnotes appear at the bottom of the page, numbered sequentially. The first citation of a source uses the full footnote form. Subsequent citations use a shortened form: Author Last Name, Shortened Title, page number. The abbreviation 'Ibid.' can be used for consecutive references to the same source.
When should I use Chicago vs APA or MLA?
Use Chicago for history, philosophy, religion, and some arts and humanities courses. Use APA for psychology, education, nursing, and social sciences. Use MLA for English literature, foreign languages, and cultural studies. Always check with your instructor or publisher for their preferred style.