The difference comes down to discipline and what each style emphasises. APA (author–date) is used in psychology, education, nursing, and the social and natural sciences. MLA (author–page) is used in literature, languages, and the humanities. Chicago offers two systems — notes-bibliography for history and the arts, and author–date for the sciences. Your instructor, journal, or publisher normally decides which one you use; when nobody specifies, follow your discipline's convention and apply it consistently.
Choosing wrongly means reformatting an entire manuscript later. This guide compares all three styles side by side in-text citations, reference lists, page setup, and current editions so you can pick correctly the first time.
Quick comparison table
| APA 7th | MLA 9th | Chicago 18th | |
|---|---|---|---|
| Current edition | 7th (2019) | 9th (2021) | 18th (2024) |
| Main disciplines | Psychology, education, nursing, business, social & natural sciences | Literature, languages, philosophy, cultural studies, humanities | History, art history, religion, publishing (NB); sciences (author–date) |
| In-text format | (Smith, 2023) | (Smith 45) | Footnote/endnote number, or (Smith 2023, 45) |
| Source list title | References | Works Cited | Bibliography (NB) or References (author–date) |
| Emphasises | Recency of research | Location in the text | Flexibility and detailed source notes |
| Title page | Required | Not usually — header block on page 1 | Varies by publisher |
| Hanging indent | Yes | Yes | Yes |
The pattern is logical once you see it. Sciences care when a study was published, so APA puts the date up front. Humanities scholars analyse specific passages, so MLA puts the page number in the citation. Historians cite archives, letters, and unusual sources, so Chicago gives them footnotes with room to comment.
APA 7th edition
APA style is published by the American Psychological Association and dominates the social and health sciences. Its author–date system signals how current the evidence is — critical when you're citing clinical or empirical research.
- In-text: (Smith, 2023) — add a page number for direct quotations: (Smith, 2023, p. 45)
- Source list: headed References, on a new page, alphabetical, double-spaced, hanging indent
- Reference example: Smith, J. A. (2023). Title of the article. Journal of Academic Writing, 12(3), 45–58. https://doi.org/10.xxxx
Note the APA-specific conventions: article titles use sentence case, journal names use title case and italics, and DOIs appear as full links. For a complete walkthrough of margins, headings, and title pages, see our APA 7th edition formatting checklist or the official APA Style paper format guidance.
MLA 9th edition
MLA style comes from the Modern Language Association and is standard across literature and the humanities — fields where you quote and analyse specific passages rather than report data. Its author–page system exists so readers can find the exact line you're discussing.
- In-text: (Smith 45) — no comma, no date
- Source list: headed Works Cited, alphabetical, double-spaced, hanging indent
- Reference example: Smith, Jane A. "Title of the Article." Journal of Academic Writing, vol. 12, no. 3, 2023, pp. 45–58.
The 9th edition builds entries from a template of core elements — author, title of source, title of container, and so on — rather than a rigid list of rules per source type. The "container" concept matters: a short story sits inside an anthology, an article inside a journal, so you document the source and then the larger whole that holds it. The official MLA Style Center and its works-cited quick guide explain the template in full.
MLA also differs on page setup: instead of a separate title page, you typically place a four-line header block (name, instructor, course, date) on the first page.
Chicago 18th edition (and Turabian)
Chicago is the most flexible of the three — and the most misunderstood, because it contains two complete citation systems. The 18th edition was released in 2024 and is the version to apply unless your publisher specifies otherwise.
1. Notes-Bibliography (NB) — used in history, art history, philosophy, and publishing. You place a superscript number in the text, and the citation goes in a footnote or endnote, with a Bibliography at the end.
- Jane A. Smith, "Title of the Article," Journal of Academic Writing 12, no. 3 (2023): 45.
Bibliography entry:
Smith, Jane A. "Title of the Article." Journal of Academic Writing 12, no. 3 (2023): 45–58.
The advantage is room to comment: a footnote can add context or a caveat without interrupting your argument.
2. Author–Date — used in the sciences and social sciences. It works much like APA: (Smith 2023, 45), with a References list at the end.
What about Turabian? Turabian (currently the 9th edition) is the student-focused adaptation of Chicago, designed for coursework, theses, and dissertations. It follows the same two systems with minor simplifications. If your university asks for Turabian, you are essentially using Chicago with student conventions.
For details on what changed in the latest edition, see the publisher's what's new in CMOS 18 or Purdue OWL's Chicago 18th edition guide.
The same source in all three styles
Seeing one article formatted three ways makes the differences concrete:
APA 7:
Smith, J. A. (2023). Title of the article. Journal of Academic Writing, 12(3), 45–58. https://doi.org/10.xxxx
MLA 9:
Smith, Jane A. "Title of the Article." Journal of Academic Writing, vol. 12, no. 3, 2023, pp. 45–58.
Chicago 18 (bibliography):
Smith, Jane A. "Title of the Article." Journal of Academic Writing 12, no. 3 (2023): 45–58.
Look at what changes: whether the author's first name is spelled out, where the year sits, whether volume and issue are labelled or numbered, and the punctuation between elements. These small differences are exactly where manuscripts lose marks and where journal editors notice inconsistency.
How to choose the right style
Work through this in order:
- Check your assignment brief, journal, or publisher guidelines. If a style is specified, that decision is made — follow it exactly, including the edition.
- If nothing is specified, follow your discipline. Sciences and social sciences → APA. Literature and languages → MLA. History and the arts → Chicago NB.
- Ask which edition. Some departments still require an older edition; using the wrong one creates avoidable errors.
- Apply it consistently. One style, one edition, throughout the whole document.
If you're targeting a journal rather than a course, its author guidelines override every general rule above — and many journals use their own house style (Harvard, IEEE, AMA, Vancouver) rather than any of these three.
Common mistakes to avoid
- Mixing styles — APA in-text citations with an MLA works-cited list is the most frequent error we see.
- Using an outdated edition, such as APA 6th or Chicago 17th, when the current one is required.
- Trusting citation generators blindly. Many tools still produce outdated or malformed entries; always check the output against the official style guide.
- Inconsistent formatting within one list — a hanging indent on some entries but not others.
- Getting
et al.rules wrong, since each style handles multiple authors differently. Our guide on when to use "et al." in citations covers the differences. - Ignoring the surrounding page setup — margins, spacing, and headings also differ by style; see our academic paper formatting rules guide.
Frequently asked questions
What is the main difference between APA, MLA, and Chicago? APA uses author–date in-text citations (Smith, 2023) with a References list and is used in the sciences. MLA uses author–page (Smith 45) with a Works Cited list and is used in the humanities. Chicago offers two systems: footnotes with a Bibliography, or author–date with a References list.
Which citation style should I use? Follow your instructor, journal, or publisher's requirement first. If none is specified, use your discipline's convention: APA for psychology, education, nursing, and the sciences; MLA for literature and languages; Chicago for history and the arts.
Is Chicago the same as Turabian? They are closely related. Turabian is the student-focused adaptation of Chicago style, designed for coursework, theses, and dissertations. It follows the same two citation systems with minor simplifications for student writing.
What is the difference between a Works Cited page and a References page? They serve the same purpose but belong to different styles. MLA calls it Works Cited, APA and Chicago author–date call it References, and Chicago notes-bibliography calls it a Bibliography. All three are alphabetical, double-spaced, and use a hanging indent.
Can I mix citation styles in one paper? No. Mixing styles is one of the most common formatting errors and signals carelessness to markers and editors. Choose one style and one edition, and apply it consistently throughout the document.
What are the current editions of each style? APA is in its 7th edition (2019), MLA in its 9th edition (2021), and Chicago in its 18th edition (2024). Confirm which edition your instructor or publisher expects before you start.
Conclusion
Citation styles are not interchangeable, but choosing between them is simpler than it looks. APA for the sciences, MLA for the humanities, Chicago for history and the art and whatever your journal or instructor specifies over all of it. Pick one, use the current edition, and apply it consistently from the first citation to the last.
If reformatting an entire reference list sounds like a poor use of your time, PaperEdit's formatting services handle APA, MLA, Chicago, Harvard, IEEE, and AMA including journal-specific house styles and our proofreading services can polish the writing at the same time.