Chicago style is the standard citation system in history and widely used across the humanities, as well as in some social science and publishing contexts.
It is also the style students most often find difficult, because the notes-bibliography system involves footnotes that change form after the first citation, a bibliography that uses a different punctuation pattern from the notes, and rules for dozens of source types, from archival letters to websites.
This guide explains how Chicago style works, the main points of the 18th edition of The Chicago Manual of Style (published in 2024), how Turabian relates to Chicago, the errors that most often cost marks, and what a Chicago style edit checks. Examples are included for the most common source types.
Chicago's two citation systems
Chicago style has two citation systems. Notes-bibliography, used mostly in history and the humanities, puts citations in numbered footnotes or endnotes with a bibliography at the end; the first note for a source is full, later notes are shortened. Author-date, used more in the sciences and social sciences, puts brief citations such as (Lepore 2018, 45) in the text with a reference list. A Chicago edit checks that every note and entry follows the right pattern, notes match the bibliography, shortened notes are used correctly, and headings, quotations and numbers follow Chicago conventions.
Notes-Bibliography vs Author-Date
| Feature | Notes-bibliography | Author-date |
|---|---|---|
| Typical fields | History, literature, arts, philosophy, theology | Physical, natural and social sciences |
| In the text | Superscript note number | Author, year and page in parentheses |
| Detail | In footnotes or endnotes | In the reference list |
| End list | Bibliography | References |
| Position of year in end list | Near the end of the entry | Directly after the author's name |
| Commentary notes | Common, alongside citations | Possible but used sparingly |
Your instructor or department decides which system you use. Mixing the two in one paper is one of the most common errors an editor corrects.
How Notes Work
In notes-bibliography style, a superscript number in the text points to a note. The first time you cite a source, the note gives the full details. Later citations of the same source use a shortened note: the author's surname, a short form of the title and the page.
First note (book): 1. Jill Lepore, These Truths: A History of the United States (W. W. Norton, 2018), 45.
Shortened note: 4. Lepore, These Truths, 112.
Bibliography entry: Lepore, Jill. These Truths: A History of the United States. W. W. Norton, 2018.
Notice the differences. The note gives the author's name in normal order and separates elements with commas, with publication details in parentheses. The bibliography inverts the first author's name and separates elements with full stops. The note includes the specific page; the bibliography entry for a book does not.
Journal Articles
Note: 2. First Author, "Title of the Article," Journal Name 12, no. 3 (2021): 58, https://doi.org/xxxxx.
Bibliography: Author, First. "Title of the Article." Journal Name 12, no. 3 (2021): 45–67. https://doi.org/xxxxx.
The note cites the page you used; the bibliography gives the full page range of the article. Article titles go in quotation marks, journal titles in italics.
What the 18th Edition Changed
The 18th edition of The Chicago Manual of Style appeared in 2024. Most of the system is unchanged, but a few points affect student papers. If your instructor still asks for the 17th edition, follow that instead; the differences are small.
- Place of publication is no longer required in book citations, so notes and entries can give just the publisher and year.
- Ibid. remains discouraged in favor of shortened notes, which are clearer when notes are read out of order.
- Digital sources receive expanded guidance, including social media, podcasts and other newer formats.
- Author-date citations and notes follow largely the same principles as before, so a paper correct under the 17th edition needs only minor adjustment.
Chicago and Turabian
Turabian is the student version of Chicago, based on Kate L. Turabian's A Manual for Writers of Research Papers, Theses, and Dissertations. It follows Chicago's citation systems but adds guidance specific to student papers, such as title pages, margins, page numbers and the layout of theses.
When an instructor says "Chicago style" for a class paper, they often mean Turabian conventions in practice. If you are unsure which edition or manual applies, ask, and tell your editor.
Chicago Errors That Cost Marks
| Error | Correct practice |
|---|---|
| Repeating the full note every time a source is cited | Full note first, shortened notes afterwards |
| Bibliography punctuation used in notes (or the reverse) | Commas and parentheses in notes; full stops in the bibliography |
| First author's name not inverted in the bibliography | Surname first for the first author only |
| Bibliography not alphabetized | Alphabetical by first author's surname |
| Note numbers placed before punctuation | Note numbers normally follow punctuation, except a dash |
| Sources in notes missing from the bibliography | Every source cited in notes appears in the bibliography (unless your instructor allows notes only) |
| Page ranges missing for articles and chapters | Full range in the bibliography, specific page in the note |
| Inconsistent capitalization of titles | Headline-style capitalization for English titles |
| Mixing author-date and notes | One system throughout |
Chicago Conventions Beyond Citations
A Chicago edit is not only about notes. The Chicago Manual of Style is a full style guide, and instructors in history and the humanities often expect its conventions in the text itself.
- Numbers: in general writing, Chicago spells out whole numbers from zero to one hundred and round numbers, and uses numerals for others (with exceptions for percentages, dates and measurements).
- Block quotations: longer quotations (around five lines or 100 words or more) are set off as indented blocks without quotation marks.
- Serial comma: Chicago uses it ("archives, letters, and diaries").
- Titles in the text: books and journals in italics; articles, chapters and poems in quotation marks.
- Dates and centuries: spelled-out centuries ("the nineteenth century") and consistent date formats.
- Headings: consistent levels, usually in headline-style capitalization.
Tricky Source Types in History and Humanities Papers
Students writing in history and the humanities often cite sources that standard examples do not cover. These are where most time goes in a Chicago edit.
| Source | Key elements to include |
|---|---|
| Archival document or letter | Writer, recipient, date, collection name, box or folder, archive and location |
| Primary source in an edited collection | Original author and title, then the editor, collection title and page |
| Chapter in an edited book | Chapter author and title, "in" book title, editor, publisher, year, page range |
| Classical or religious texts | Traditional divisions (book, chapter, verse or line) rather than page numbers, with the edition or translation noted |
| Newspaper article | Author, headline, newspaper name, date, and URL if consulted online |
| Website or online source | Author or owner, page title, site name, date of publication or revision, URL |
| Source quoted in another source | Cite the original if possible; otherwise note "quoted in" with both sources |
Author-Date Examples
If your department uses the author-date system, the in-text citation is brief and the detail moves to the reference list. The year comes straight after the author's name in the reference list, so readers can match the two quickly.
In text: (Lepore 2018, 45)
Reference list: Lepore, Jill. 2018. These Truths: A History of the United States. W. W. Norton.
Two works by the same author in one year: add letters (2018a, 2018b) in both the text and the reference list.
Worked Example: A Note Sequence Before and After Editing
Before:
1 Lepore, Jill. These Truths. New York: W. W. Norton, 2018. p. 45
2 Ibid.
3 Jill Lepore, These Truths: A History of the United States (New York: W. W. Norton, 2018), 112.
Problems: note 1 uses bibliography punctuation, an inverted name, no italics and "p." before the page; note 2 relies on ibid.; note 3 repeats a full note for a source already cited.
After:
1. Jill Lepore, These Truths: A History of the United States (W. W. Norton, 2018), 45.
2. Lepore, These Truths, 45.
3. Lepore, These Truths, 112.
Across a paper with 60 or 80 notes, small inconsistencies like these add up quickly, which is why markers in history often treat note formatting as evidence of care with sources.
What a Chicago Style Edit Checks
- Which system is used, and that it is used consistently.
- Every first note is complete and correctly punctuated for its source type.
- Shortened notes are used for later citations and match the full note.
- Note numbers run in sequence and sit in the right place relative to punctuation.
- Every cited source appears in the bibliography, alphabetized and correctly formatted.
- Page numbers appear in notes, and page ranges in bibliography entries where needed.
- DOIs or URLs are included for online sources.
- Numbers, quotations, titles and headings follow Chicago conventions.
- Title page, margins and page numbers follow Turabian or your instructor's template.
How GradeEssays Helps
Send your paper, tell us which Chicago system and edition (or Turabian) you use, and include your instructor's instructions or template. An editor familiar with Chicago returns tracked changes on every note, shortened note and bibliography entry, along with corrections to numbers, quotations and headings.
Where a citation is missing information we cannot verify, such as an archive box number, we flag it for you to fill in rather than guess. Revisions within the scope of your original request are free, and your identity is never shared with the editor.
Get Every Note and Entry Right
Send your paper, your style (Chicago or Turabian, notes or author-date) and your instructor's requirements. An editor checks every citation with tracked changes.
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Frequently Asked Questions
Notes-bibliography uses numbered footnotes or endnotes with a bibliography and is common in history and the humanities. Author-date uses parenthetical citations with a reference list and is common in the sciences.
The 18th edition of The Chicago Manual of Style, published in 2024. Follow the edition your instructor specifies.
Chicago discourages ibid. in favor of shortened notes, though it is not forbidden. Follow your instructor's preference.
Turabian follows Chicago's citation systems but adds guidance for student papers, such as title pages, margins and thesis layout.
Usually yes. Most instructors expect a bibliography with notes-bibliography style, although Chicago allows notes alone when full notes are given. Check your assignment instructions.
After the punctuation of the clause or sentence they refer to, except before a dash, and normally at the end of a sentence or clause.
Yes. We edit Chicago and Turabian theses and dissertations, including notes, bibliography and graduate school formatting.
We flag it with a comment so you can add the missing information. We never invent publication details.
Either is correct in Chicago. Footnotes are more common in student papers because readers see the source on the same page; follow your instructor's preference and use one type consistently.
Not under the 18th edition, which allows notes and bibliography entries to give only the publisher and year. If your instructor requires the 17th edition, include the city.
A short paper with a few dozen notes can often be checked within a day. Long theses with archival sources need several days. Deadlines run from 3 hours to 20 days.