Citation Styles Compared
APA, MLA, Chicago, Turabian, Harvard and IEEE side by side: who uses each one, how in-text citations work, and the author rules that catch people out.
The styles at a glance
| APA | MLA | Chicago | Harvard | IEEE | |
|---|---|---|---|---|---|
| Used in | Psychology, education, social sciences, nursing | Literature, languages, humanities | History, arts, philosophy | UK & Australian universities, business | Engineering, computer science |
| In-text | (Nguyen, 2021, p. 4) | (Nguyen 4) | Footnote¹ | (Nguyen, 2021, p. 4) | [1] |
| List title | References | Works Cited | Bibliography | Reference list | References |
| List order | Alphabetical | Alphabetical | Alphabetical | Alphabetical | Order of citation |
| Author names | Nguyen, T. L. | Nguyen, Thi Lan | Nguyen, Thi Lan | Nguyen, T.L. | T. L. Nguyen |
| “et al.” from | 3 authors (in text) | 3 authors | 4 (notes) | 4 authors | 7 authors |
| Date position | After author | Near the end | End of publication facts | After author | Near the end |
| Title case | Sentence case | Title Case | Title Case | Sentence case | Sentence case (articles) |
| Manual | APA Publication Manual, 7th ed. | MLA Handbook, 9th ed. | Chicago Manual of Style, 17th ed. | Cite Them Right, 12th ed. | IEEE Reference Guide |
Turabian follows Chicago’s citation formats; it adds student-paper layout rules.
How many authors before “et al.”?
The rule people get wrong most often, and it’s different in every style. Move the slider and watch each style’s author list change.
Watch where each style switches to “et al.”: 3 authors (APA and MLA in text), 4 (Harvard and Chicago notes), 7 (IEEE), and 21 (the APA reference list).
| Style | Reference list author part | In text / note |
|---|---|---|
| APA 7Every author is named in text. | Okafor, A. | (Okafor, 2023, p. 104) |
| MLA 9One author, name inverted. | Okafor, Ada | (Okafor 104) |
| Chicago 17All names in the note. | Okafor, Ada | Ada Okafor, … |
| HarvardUp to three authors are all named. | Okafor, A. | (Okafor, 2023, p. 104) |
| IEEEUp to six authors, initials first. | A. Okafor | [1, p. 104] |
APA vs MLA: the short answer
Both are the styles students meet first, and they look similar enough to mix up. The difference comes from what each field values. APA (social sciences) puts the year up front because research ages; its in-text citations read (Nguyen, 2021). MLA (humanities) puts the page up front because you quote texts closely; its in-text citations read (Nguyen 4).
Other differences follow from that: APA titles use sentence case, MLA uses title case; APA uses initials, MLA full first names; APA writes “&” between authors, MLA writes “and”.
Which style should you use?
Always use the style your assignment brief, department handbook or journal specifies. That overrides everything else. If you get to choose, match the field:
- Psychology, education, nursing, business, sociology: APA
- English, literature, languages, cultural studies: MLA
- History, art history, theology, philosophy: Chicago or Turabian
- Most subjects at UK and Australian universities: Harvard
- Electrical engineering, computer science, IT: IEEE
Why cite sources at all?
Citations let a reader find exactly what you read, give credit to the people whose work you build on, and show which ideas are yours. Leaving them out, even by accident, can count as plagiarism under most universities’ academic integrity policies. Cite whenever you quote, paraphrase, summarise, or use someone’s data, images or distinctive ideas. Common knowledge, such as the fact that water boils at 100 °C at sea level, doesn’t need a citation.