Before you format a Chicago citation, settle which citation system your assignment requires. Chicago offers notes and bibliography and author-date, and the choice shapes both the citations in your paper and the full entries that accompany them. You can approach the task in a clear order: confirm the system, collect the source details, consult a matching example, and check that the reader can connect each citation to the right source.
The Manual and Its 18th Edition
The University of Chicago Press describes The Chicago Manual of Style as now in its 18th edition, with text copyright 2024. The first edition appeared in 1906. The Press describes the 18th edition as an extensive revision covering publishing technologies, accessibility, inclusive language, and source citations, with changes across every chapter.
For your assignment, confirm which edition your instructor expects before choosing examples. Keep a note of that requirement beside your source records so you can use it throughout drafting and revision. When you encounter differing guidance, identify the edition and citation system behind each example rather than choosing whichever format looks easiest.
Two Systems, One Style
The Chicago-Style Citation Quick Guide explains both systems. In notes and bibliography, a raised number in the text points to a numbered footnote or endnote. Sources are usually also listed in a separate bibliography. Many writers in the humanities, including history, literature, and the arts, prefer this system because it can accommodate varied and unusual sources.
In author-date, the brief citation usually appears in parentheses and gives the author's last name and the publication year. Each in-text citation corresponds to an entry in a reference list with full bibliographic details. Many writers in the sciences and social sciences prefer this system, which emphasizes both the researcher's name and the source's date.
Think about the connection the reader follows. With notes and bibliography, the text points to a note; with author-date, the name and year point to a reference-list entry. Keep that connection clear as you draft. Before polishing punctuation, make sure you have identified the source correctly and can find the full information needed for its entry.
Choosing Between Them
Chicago advises students to check with their instructor before deciding which system to use. A preference common in your field is useful context, but your assignment's directions should guide the choice. Look for a named system in the prompt or course materials. If the instruction says only Chicago, ask whether notes and bibliography or author-date is expected.
Once you have the answer, write it at the top of your working notes. Use examples for that system throughout your paper. A useful question when comparing examples is: am I looking at a note, a bibliography entry, an in-text citation, or a reference-list entry? Identify its role before treating it as a model. That habit keeps you focused on the format your paper actually needs.
Where to Look in the Manual
The quick guide points to chapter 13 for a comprehensive overview of Chicago's two source-citation systems and chapter 14 for further examples organized by source type. Begin with the overview if you are unsure how your citations should connect. Turn to the examples when you know the system and need to format a particular source.
Keep the source open while consulting an example. Identify what you actually read and record its details rather than guessing from an incomplete note. If a source does not fit the example you found, consult further guidance or ask your instructor or library for help. Leave a clear reminder of the unresolved question in your draft so you can return to it before submitting.
Habits That Keep Chicago Citations Clean
Record author, title, publication details, date, and relevant page locations while reading. Keep quotations clearly marked and separate from your own notes. When you paraphrase, retain the connection to the source so that an idea does not lose its attribution as you revise. Our guide to avoiding plagiarism explains that everyday citation discipline.
Review the paper from the reader's point of view. Follow each citation to the note or full entry it points toward, compare the details with the source, and resolve any mismatch. Keep your chosen system consistent from beginning to end, and check your instructor's requirements before the final proofread. Correct formatting should make your evidence easy to trace while leaving room for your own argument.