Direct comparison
APA vs Chicago vs MLA: Key Differences
APA vs Chicago vs MLA compared side by side. Explore in-text citations, bibliography layouts, title capitalization rules, and which style fits your field.
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How do APA (7th ed.), Chicago (18th ed.), MLA (9th ed.) compare side by side?
The table below compares APA (7th ed.), Chicago (18th ed.), MLA (9th ed.) across 12 procurement-relevant dimensions, from primary discipline focus through source.
Side-by-side comparison
| Dimension | APA (7th ed.) | Chicago (18th ed.) | MLA (9th ed.) |
|---|---|---|---|
| Primary discipline focus | Social and behavioral sciences: psychology, sociology, education, nursing, health sciences, and business. | Humanities (history, art history, philosophy, religion) via Notes-Bib; physical, natural, and social sciences via Author-Date. | Humanities: English literature, comparative literature, modern languages, cultural studies, theater, and arts. |
| Citation systems offered | Single Author-Date parenthetical system paired with a comprehensive References list. | Dual systems: Notes & Bibliography (numbered notes + bibliography) and Author-Date (parenthetical + references). | Single Author-Page parenthetical system paired with a Works Cited list built on core container elements. |
| In-text citation format | Author-Date: (Smith, 2023) or narrative Smith (2023). Direct quotations require page numbers: (Smith, 2023, p. 45). | Notes-Bib: Superscript numbers¹ keyed to footnotes/endnotes. Author-Date: (Smith 2023, 45) without a comma before the year. | Author-Page: (Smith 45) without a comma or publication year. Direct narrative: Smith notes that... (45). |
| Multiple authors in text (et al.) | 1-2 authors: spell out both (Smith & Doe, 2023). 3+ authors: shorten to first author + et al. from the very first citation. | 1-2 authors: spell out both. 3+ authors: shorten to first author + et al. (CMOS 18th 13.23). Notes system uses shortened notes on subsequent citations. | 1-2 authors: join with "and" (Smith and Doe 45). 3+ authors: shorten to first author + et al. in parenthetical citations. |
| Name of final source list | References (centered, bold at top of new page). | Bibliography (Notes & Bibliography system) or References (Author-Date system), centered at top of new page. | Works Cited (centered, non-bold, non-italicized at top of new page). |
| Author name formatting in list | Inverted names with initials only: Smith, J. A., & Doe, B. R. Up to 20 authors listed before using ellipses. | First author inverted with full first name: Smith, Jane A., and John Doe. Up to 6 authors listed; >6 authors use first 3 + et al. | First author inverted with full first name: Smith, Jane A., and John Doe. 3+ authors list first author + et al. |
| Year placement in reference entry | Placed immediately after author name in parentheses: Smith, J. A. (2023). Article title. | Notes-Bib: Placed near the end within publication details. Author-Date: Placed immediately after author without parentheses: Smith, Jane A. 2023. | Placed near the end of the container entry following volume, issue, or publisher details: ...vol. 12, no. 3, 2023, pp. 45-58. |
| Title capitalization rules | Sentence case for article and book titles (capitalize only first word, first word after colon, and proper nouns). Periodical titles in Title Case. | Headline / Title Case for all titles: books, journals, book chapters, and periodical articles. | Headline / Title Case for all source titles and container names. |
| Block quotation thresholds | 40 words or more: indented 0.5 in from left margin, double-spaced, no quotation marks; parenthetical citation follows final punctuation. | Prose of 5+ lines or 100+ words (poetry 2+ lines): indented 0.5 in, typically single-spaced, no quotation marks. | Prose of more than 4 lines (poetry 4+ lines): indented 0.5 in from left margin, double-spaced, no quotation marks; citation follows period. |
| Title page and layout standards | Title page required (distinct student vs professional standards; professional requires running head <= 50 characters). 1-inch margins, double-spaced. | Formal title page required for academic theses and book manuscripts. 1-inch margins; double-spaced text with single-spaced footnotes. | No separate title page required by default; four-line header block on page 1 (name, instructor, course, date); last name + page number top right. |
| When to pick each | Pick when writing in behavioral or social sciences where empirical methodology, study currency, and quantitative findings are prioritized. | Pick Notes-Bib for history, religion, or philosophy requiring discursive footnote analysis; pick Author-Date when target journal specifies CMOS. | Pick for literature, languages, and humanities papers requiring close textual analysis, direct line quotations, and container-based media tracking. |
| Source | APA Publication Manual 7th ed. (2020); APA Style Instructional Aids (read 2026-10-28 and 2026-11-11). | The Chicago Manual of Style 18th ed. (2024), CMOS What's New §13.23, §14.30 (read 2026-10-28 and 2026-11-11). | MLA Handbook 9th ed. (2021); Modern Language Association Style Center & Purdue OWL (read 2026-10-28 and 2026-11-11). |
Common questions
Common questions about APA (7th ed.) vs Chicago (18th ed.) vs MLA (9th ed.)
What is the primary difference between APA, Chicago, and MLA styles?
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The primary difference lies in disciplinary focus and citation mechanics. APA (social sciences) uses an author-date format (Smith, 2023) emphasizing research recency; Chicago Notes-Bibliography (history and arts) uses numerical footnotes and a bibliography for detailed source commentary; and MLA (humanities and literature) uses an author-page format (Smith 45) focusing on exact textual locations within modular containers.
How do in-text citations differ across APA, Chicago, and MLA?
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APA uses parenthetical author and year separated by a comma (Smith, 2023), adding 'p.' for page numbers (Smith, 2023, p. 45). Chicago Notes-Bibliography uses superscript footnote numbers corresponding to citations at the bottom of the page, while Chicago Author-Date uses (Smith 2023, 45) without a comma between author and year. MLA uses author and page number with no comma and no year (Smith 45).
What are the reference list names in APA, Chicago, and MLA?
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At the end of a paper, APA titles its list References, Chicago Notes-Bibliography uses Bibliography (while Chicago Author-Date uses References), and MLA titles its list Works Cited. Each list follows strict alphabetical ordering with a 0.5-inch hanging indent.
Do APA, Chicago, and MLA all require a title page?
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No. APA requires a title page for both student and professional papers (with distinct header rules). Chicago typically requires a dedicated title page for formal research papers and theses. MLA does not require a separate title page by default; instead, it uses a four-line header block placed on the first page above the paper title.
Going deeper
