While the rules regarding footnotes vary according to the citation style used, there are two distinct purposes for footnotes:
- To provide necessary information to text in the form of a citation.
- To provide supplementary information to text, such as clarifying an idea or expounding on it for further inquiry.
Regardless of their purpose, a footnote is usually added to text as a superscript, starting at 1, and with a corresponding number at the bottom of the page (known as the footer) where the citation or additional information is included.
See the example below, which shows the superscripted footnote numbers, along with the footnotes and the way they are formatted on the paper. Keep in mind that the gray line is the bottom of the paper, so your footnotes will be printed that close to the end of the page.
Why are footnotes used?
Footnotes are the least intrusive way for an author to provide citations or supplemental information about a topic. In some cases, such as when using Chicago Style, footnotes are often used instead of in-text citations with a bibliography at the end of the paper. Footnotes allow an author to guide his or her reader to additional information or further study, without disrupting the flow of the sentence.
Another great use of footnotes is to define or explain a word or idea that might require further explanation to a general audience. A definition or explanation can be provided within the footnote without any visual or logical disruption in the text.
Style guides and footnotes
The Chicago Manual of Style (CMS) requires the use of footnotes instead of in-text citations. Other styles, such as the Modern Language Association (MLA) and the American Psychological Association (APA) also allow the use of footnotes. However, while CMS requires footnotes for citations and supplemental information, APA and MLA suggest footnote use for supplemental information only.
Modern Language Association's (MLA) rules regarding footnote use
Below are the rules regarding footnote use in MLA style, taken from the Purdue Online Writing Lab.
- MLA discourages extensive use of explanatory or digressive notes.
- MLA Style does, however, allow you to use endnotes or footnotes for bibliographic notes, which refer to other publications your readers may consult.
Following are some examples:
- See Blackmur, especially chapters 3 and 4, for an insightful analysis of this trend.
- On the problems related to repressed memory recovery, see Wollens 120-35; for a contrasting view, see Pyle 43; Johnson, Hull, Snyder 21-35; Krieg 78-91.
- Several other studies point to this same conclusion. See Johnson and Hull 45-79, Kather 23-31, Krieg 50-57.
Or, you can also use endnotes/footnotes for occasional explanatory notes (also known as content notes), which refers to brief additional information that might be too digressive for the main text:
- In a 1998 interview, she reiterated this point even more strongly: "I am an artist, not a politician!" (Weller 124).
MLA style has a few additional rules concerning footnote use:
- For footnotes placed in dependent clauses, such as this one,1 add the number after the comma.
- Footnotes should follow the period at the end of a sentence.2
- The only exception to a footnote following the punctuation would be this one3—the dash. When a dash is used as punctuation following a word, the footnote connected to that word should come before it.
American Psychological Association's (APA) rules regarding footnote use
APA style discourages the use of footnotes and endnotes, according to the Purdue Online Writing Lab, as detailed below.
- APA does not recommend the use of footnotes and endnotes because they are often expensive for publishers to reproduce. However, if explanatory notes still prove necessary to your document, APA details the use of two types of footnotes: content and copyright. When using either type of footnote, insert a number formatted in superscript following almost any punctuation mark.
- Footnote numbers should not follow dashes ( — ), and if they appear in a sentence in parentheses, the footnote number should be inserted within the parentheses.
- Scientists examined—over several years1—the fossilized remains of the wooly-wooly yak.2
- (These have now been transferred to the Chauan Museum.3).
Also keep in mind, when using the footnote function in a word-processing program like Microsoft Word®, place all footnotes at the bottom of the page on which they appear. Footnotes may also appear on the final page of your document (usually this is after the References page). Center the word "Footnotes" at the top of the page. Indent five spaces on the first line of each footnote. Then, follow normal paragraph spacing rules. Double-space throughout:
1 While the method of examination for the wooly-wooly yak provides important insights to this research, this document does not focus on this particular species.
Chicago Manual of Style rules regarding footnote use
The Chicago Manual of Style (CMS) uses footnotes as the primary way to cite sources. While in-text citations can be used, footnotes are most typical for this style. As with MLA, the footnotes should follow the punctuation unless the punctuation is a dash. There are more specific rules regarding footnote placement and numbering for this style that can be found the Purdue Online Writing Lab.
Footnote examples for all style guides
Scientists have discovered varied lifeforms in this habitat.6
I'm allergic to shellfish,7 so let's not order the shrimp.
For years, scholars have studied the book carefully8—a fact that suggests there has been much effort put into understanding it.