Chicago Footnotes
Updated October 2026
In Chicago's notes-bibliography system, you cite with a superscript number that points to a footnote at the bottom of the page. The first note for a source is full; later notes are shortened. The bibliography entry at the end holds the same information in a different shape.
Full note vs. short note
Full (first time): 1. First Last, Title of Book (City: Publisher, Year), 45. Short (after that): 2. Last, Short Title, 78.
The first time you cite a source, the footnote gives full details and the specific page. Every time after, use the short form: author's last name, a shortened title, and the page. Note that footnotes use commas and parentheses and are not inverted — unlike the bibliography entry, which inverts the author and uses periods.
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Citation style
The Chicago Manual of Style, 18th edition (2024), notes and bibliography. The 18th dropped the place of publication that the 17th required.
Note vs. bibliography entry
They contain the same facts in different forms. The note reads like a sentence: 1. Björn Rasch and Jan Born, "About Sleep's Role in Memory," Physiological Reviews 93, no. 2 (2013): 685. The bibliography entry inverts the first author and uses periods: Rasch, Björn, and Jan Born. "About Sleep's Role…". Generate the bibliography entry here and you have everything the first note needs.
Ibid. and consecutive citations
- Short note is preferred for repeat citations — Chicago has de-emphasized ibid. since the 17th edition, and the 18th keeps that preference.
- Ibid. may still be used for a citation immediately following the same source — it means "in the same place."
- Footnotes vs. endnotes — same content; footnotes sit at the page bottom, endnotes collect at the chapter/document end. Your instructor or publisher chooses.
- Superscript numbers go after the punctuation in your text, numbered consecutively.
When to use this system
Notes-bibliography is the Chicago variant for history and the humanities. The sciences use Chicago author-date (parenthetical, like APA). If your instructor mentions footnotes, you want this system. More in the Chicago Citation Generator and References vs Bibliography.
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Go Premium — $5/monthFrequently asked questions
- What's the difference between a full and short footnote?
- The first note for a source is full (author, title, publication details, page). Every later note is shortened to last name, short title, and page.
- How is a footnote different from the bibliography entry?
- The footnote is sentence-style with commas and a non-inverted name; the bibliography entry inverts the first author and uses periods. Same facts, different shape.
- Should I still use 'ibid.'?
- Chicago 18th prefers the shortened note over ibid., though ibid. is still acceptable for a source cited immediately again.
- Footnotes or endnotes?
- Either — same content. Footnotes appear at the bottom of the page, endnotes at the end of the chapter or document. Follow your instructor's or publisher's preference.