Ask five instructors which citation style to use and you’ll sometimes get five different answers. Then a returned draft covered in red ink, because the version you used wasn’t quite the one they meant. APA, MLA, and Harvard aren’t interchangeable, and the differences aren’t cosmetic. Get them wrong and a reader who knows the format will notice before they’ve read your first paragraph.
Start with who’s grading it, not what you prefer
Citation style is rarely your choice to make. Check your assignment brief, your department’s style guide, or the target journal’s author guidelines first; that single check saves more rework than anything else in this article. If nothing is specified, the discipline usually decides for you. Psychology, education, and the social sciences default to APA. Literature, languages, and the humanities lean MLA. Harvard (or a close variant of it) shows up constantly in UK, Australian, and business-school writing.
APA (7th edition): built for the sciences
APA in-text citations use an author-date format, like (Smith, 2021), because in scientific writing, how recent a finding is usually matters as much as who found it. The reference list is alphabetical by author surname, and APA is strict about things a lot of writers skip: a DOI or URL for anything found online, sentence-case (not title-case) for article titles, and a hanging indent on every entry. A common mistake is treating APA and MLA reference-list formatting as interchangeable. They aren’t, right down to how italics and punctuation are used.
MLA (9th edition): built for close reading
MLA also uses an in-text system, but by author and page number, like (Smith 42), because in literary analysis, the reader usually wants to find the exact line you’re quoting, not just confirm when it was published. The “Works Cited” page (not “References,” which is an APA-ism that shows up in MLA papers more often than you’d think) uses a container system: a poem inside a collection, an article inside a journal, an episode inside a series. Once you learn the container logic, most MLA citations become a fill-in-the-blank exercise.
Harvard: the flexible one, which is also the trap
“Harvard” isn’t a single fixed standard the way APA and MLA are. It’s a family of author-date styles, and your university almost certainly has its own house variant with its own quirks around punctuation, capitalization, and how to handle secondary sources. This is exactly why Harvard citations cause more inconsistent-formatting feedback than the other two styles: writers assume “Harvard” means one thing, follow a generic online guide, and then get marked down against their specific institution’s actual style sheet. Always pull your university’s own Harvard referencing guide before you start, not a general one from a search engine.
The habit that matters more than memorizing any style
Pick your style before you start drafting, not after. Reformatting fifty sources from MLA to APA the night before a deadline is a miserable way to spend an evening, and it’s when small errors (a missing issue number, an inconsistent date format) slip through. A reference manager (Zotero and Mendeley are both free) will save you hours over a long paper, but it won’t catch a citation style that’s simply wrong for your discipline. That judgment call is still yours.
If you’d rather have someone check your citations and formatting line by line before submission, that’s exactly what our Language Refinement service covers, alongside broader manuscript polish. In the meantime, our free citation generator and citation cross-checker can catch some of the mechanical issues yourself before you send anything over. And if you’re at the stage of structuring a longer document around your sources, see how our process works from first draft to final submission.