APA vs MLA vs Chicago: Clear Rules with Side-by-Side Examples

APA, MLA, and Chicago are the three most-used academic citation styles. APA uses author–date in-text citations and a References list, MLA uses author–page and a Works Cited, while Chicago offers Notes & Bibliography (footnotes) or Author–Date. Choose by discipline or your instructor’s guide, then format consistently across the paper.

Table of contents:

1. When to use each style

2. Core formatting at a glance

3. In-text citations: how they differ

4. Reference entries compared

5. Practical workflow for 2025

When to use each style

Most instructors and journals signal their preferred style. When they don’t, use the rule of thumb: APA for social sciences and STEM-adjacent fields, MLA for the humanities and language arts, and Chicago for history, arts, and interdisciplinary projects. Chicago uniquely offers two systems: Notes & Bibliography (NB)—footnotes plus a bibliography—and Author–Date (AD), which resembles APA’s in-text approach.

If your course spans multiple disciplines—say, digital humanities or science communication—prioritize the audience and publishing venue. A policy memo for a public administration class usually reads best in APA; a literature analysis belongs in MLA; a museum catalog essay or archival study often sits comfortably in Chicago NB. When in doubt, mirror the style used in your syllabus readings and confirm with your instructor.

Two more practical signals:

• Quotation density. Projects with many primary-source quotations (poems, archival letters, historical documents) tend to benefit from Chicago NB, because footnotes preserve a clean reading flow while keeping citations precise.

• Currency of research. Empirical work that emphasizes recency—health, psychology, policy, business—usually picks APA, because the year is visible in every in-text citation.

Core formatting at a glance

Across all three, keep 1-inch margins, double spacing, readable 11–12 pt fonts, and page numbers. The rest differs in small but important ways.

Title page and headers

• APA (student papers): separate title page with paper title, author, affiliation, course, instructor, and due date. Page numbers in the top right; no running head is required for most student papers.

• MLA: usually no separate title page; student name, instructor, course, and date appear as a block at top left of the first page, with a centered title on the next line. The header shows the LastName page in the top right.

• Chicago: many instructors prefer a separate title page. In NB, use superscript numbers for notes; in AD, prepare a references list similar to APA.

Headings

• APA: structured headings in levels; Level 1 is bold, centered, Title Case.

• MLA: headings are optional and less formal; use Title Case, same font, no bold by default unless your instructor allows it.

• Chicago: flexible; follow your instructor or publisher’s house style.

Quick comparison table

Key takeaway: APA foregrounds the year, MLA foregrounds page numbers, and Chicago NB foregrounds provenance via notes. Whichever you choose, consistency beats perfection—mixed rules are the most common grading deduction.

In-text citations: how they differ

The first place style shows up to your reader is inside the paragraph. Here’s what changes—and what stays the same.

APA (Author–Date)
APA in-text citations provide author and year, with page or paragraph numbers for direct quotes. For three or more authors, use et al. from the first citation. Narrative and parenthetical styles are both correct.

• Paraphrase: (Lopez et al., 2023) or Lopez et al. (2023) argue that…

• Direct quote: (Lopez et al., 2023, p. 58)

• Group author: (World Health Organization, 2024)

• No author: Use the title in Title Case and the year: (“Global Learning Report,” 2025)

MLA (Author–Page)
MLA emphasizes page location rather than publication year. If a work has three or more authors, cite the first author + et al. Include line or paragraph numbers for poetry or web texts when relevant.

• Paraphrase: (Lopez et al. 58) or Lopez et al. argue that… (58)

• Poetry: (O’Hara, line 12)

• No author: Use a shortened title in quotation marks: (“Global Learning Report” 12)

Chicago NB (Footnotes) and AD (Author–Date)
With Notes & Bibliography, place a superscript number at the end of the sentence. The corresponding footnote (or endnote) holds the full citation the first time, and a shortened form thereafter. With Author–Date, Chicago looks similar to APA but keeps its own punctuation rules.

• NB footnote marker: …as demonstrated in recent fieldwork.^1

• AD paraphrase: (Lopez 2023, 58)

Quotations, block quotes, and paraphrases discipline
All three styles require a distinct block format for longer quotations (length thresholds vary, but ~40 words in APA and prose of four lines in MLA are common). Quote sparingly and paraphrase accurately; for statistics or contested claims, retain page numbers even in paraphrases, because it speeds up verification for graders.

Multiple works and repeated citations

• APA: (Lopez, 2023; Kim, 2021; Patel, 2019) sorted by year; same author, different years: (Lopez, 2021, 2023).

• MLA: separate with semicolons: (Lopez 58; Kim 14–15); add letters for same-year sources in the Works Cited (2023a, 2023b) but the letters do not show in in-text MLA—only authors and pages do.

• Chicago NB: the short note (Author, Short Title, page) keeps reading smooth after the first full note.

Reference entries compared (books, journal articles, web pages)

Formatting the final list is where small punctuation differences matter. Below, each example uses the same fictional sources so you can compare structure at a glance. Replace the placeholders with your real data.

Books

APA — References
Lopez, A., Kim, R. J., & Patel, N. (2023). Learning in complex systems: A practical introduction (2nd ed.). Northbridge Press.

MLA — Works Cited
Lopez, Adriana, et al. Learning in Complex Systems: A Practical Introduction. 2nd ed., Northbridge Press, 2023.

Chicago — Bibliography (NB)
Lopez, Adriana, Rebecca J. Kim, and Nikhil Patel. Learning in Complex Systems: A Practical Introduction. 2nd ed. Northbridge Press, 2023.

Chicago — References (AD)
Lopez, Adriana, Rebecca J. Kim, and Nikhil Patel. 2023. Learning in Complex Systems: A Practical Introduction. 2nd ed. Northbridge Press.

Journal articles

APA
Kim, R. J., & Lopez, A. (2024). Rethinking instructional feedback loops. Journal of Applied Pedagogy, 19(3), 211–234. https://doi.org/10.1234/jap.2024.5678

MLA
Kim, Rebecca J., and Adriana Lopez. “Rethinking Instructional Feedback Loops.” Journal of Applied Pedagogy, vol. 19, no. 3, 2024, pp. 211–234. https://doi.org/10.1234/jap.2024.5678.

Chicago — Bibliography (NB)
Kim, Rebecca J., and Adriana Lopez. “Rethinking Instructional Feedback Loops.” Journal of Applied Pedagogy 19, no. 3 (2024): 211–234. https://doi.org/10.1234/jap.2024.5678.

Chicago — References (AD)
Kim, Rebecca J., and Adriana Lopez. 2024. “Rethinking Instructional Feedback Loops.” Journal of Applied Pedagogy 19 (3): 211–234. https://doi.org/10.1234/jap.2024.5678.

Web pages

APA
Patel, N. (2025, April 2). Designing dashboards students actually use. EdTech Studio. https://example.com/dashboards

MLA
Patel, Nikhil. “Designing Dashboards Students Actually Use.” EdTech Studio, 2 Apr. 2025, https://example.com/dashboards.

Chicago — Bibliography (NB)
Patel, Nikhil. “Designing Dashboards Students Actually Use.” EdTech Studio. April 2, 2025. https://example.com/dashboards.

Formatting cues to watch: APA capitalizes sentence case for article and chapter titles; MLA and Chicago use Title Case. APA prefers DOI links; MLA is comfortable with DOI or URL; Chicago NB often adds an access date for unstable pages if your instructor requests it.

Common edge cases, resolved

• Multiple authors: APA switches to et al. at three+ authors in-text from the first mention; MLA uses et al. for three+ as well; Chicago NB uses a condensed short note after the first full note.

• Corporate authors: Write the organization as the author. In APA, repeat the organization in the in-text citation if it is the author; in MLA, treat it like a named author; in Chicago NB, do the same in notes.

• No date: Use n.d. in APA; omit the date in MLA if unpredictable, or include it if visible; Chicago often writes n.d. in AD and specifies “n.d.” or no date in NB with context.

Practical workflow for 2025

The quickest way to get this right is to decide style first, then lock your document to that style’s “muscle memory.” Start a new file or template with margins, header, font, and heading rules set up. Add placeholder text for your title block (APA title page or MLA header) so you never mix elements mid-draft.

As you research, record full citation metadata immediately: authors, year (or date), page range, edition, DOI/URL. Don’t trust your memory; the cost of hunting for missing page numbers rises steeply at the end. If you’re using a reference manager, map it to the exact style and fix capitalization rules (APA sentence case vs Title Case) manually for titles—it’s the most common automated error.

When paraphrasing, keep your source on the left and your draft on the right. Write the idea in your own words without looking at the original sentence structure, then glance back to confirm accuracy. If a statistic or wording is distinctive, quote briefly and add the precise locator (page or paragraph). For statistics that recur, place a short parenthetical right after the figure; graders often scan for numbers and verify them immediately.

Before submission, walk through three passes. First, a formatting pass: title/page setup, heading levels, line spacing, paragraph indents, figure/table captions. Second, a citations pass: every in-text mention must have a matching entry, and every entry must be cited at least once. Third, a semantics pass: check capitalization by style, punctuation (periods before/after parentheses differ), and the et al. and ampersand rules (APA uses & inside parentheticals but and in narrative; MLA always uses and).

If you use assistive tools or drafting software, preserve your writing trail—early outlines, dated drafts, and note files. That archive helps you explain your process and avoid false positives in automated checks. Keep a final references audit page: paste each in-text citation and its final entry beneath it; mismatches pop out visually.

Finally, remember the purpose: citations are a reader service. The point is to let a curious reader trace your ideas in minutes. If you’re debating a tiny punctuation detail vs. clarity, choose clarity and follow the spirit of the style—then keep it consistent across the whole document.