How to Format References in APA, MLA, Chicago, and Harvard

How to format references depends on which style you are writing in, but every style splits the job into the same two halves: the rules for each entry (element order, capitalization, punctuation) and the rules for the list as a page (its title, its order, its spacing, its indentation). Most lost marks come from the second half, because it is the half nobody looks up. This guide covers the page rules for APA 7, MLA 9, Chicago 18, and Harvard, shows one real book formatted in all four, then covers the numbered styles and the Word mechanics that make the list hold its shape.

One book, four styles

Seeing the same source formatted four ways is the fastest route to understanding what each style actually asks for. The book is Susan Cain's Quiet, published by Crown Publishers in 2012. In every style below, the book title is italicized in your document.

APA 7th edition:

Cain, S. (2012). Quiet: The power of introverts in a world that can't stop talking. Crown Publishers.

MLA 9th edition:

Cain, Susan. Quiet: The Power of Introverts in a World That Can't Stop Talking. Crown Publishers, 2012.

Chicago 18th edition (bibliography entry):

Cain, Susan. Quiet: The Power of Introverts in a World That Can't Stop Talking. Crown Publishers, 2012.

Harvard (Cite Them Right):

Cain, S. (2012) Quiet: the power of introverts in a world that can't stop talking. New York: Crown Publishers.

Four details do most of the differentiating work:

• The author's given name. APA and Harvard reduce it to initials. MLA and Chicago spell it out as it appears on the title page.
• The year's position and punctuation. APA and Harvard put the year right after the author, because their in-text citations are author-date pairs and the reference list mirrors that. APA wraps the year in parentheses with a period after; Harvard uses parentheses with no period. MLA and Chicago hold the year until the end of the entry.
• Title capitalization. APA and Harvard use sentence case for book titles (capitalize the first word, the first word after a colon, and proper nouns). MLA and Chicago use title case.
• The place of publication. Harvard, in the Cite Them Right version, still asks for it before the publisher. Chicago dropped it in the 18th edition for books published since 1900, which is why the Chicago and MLA entries above look identical for this particular book. They diverge again on sources with more elements, and Chicago pairs the entry with numbered footnotes where MLA uses parenthetical citations.

The in-text forms differ just as much: APA writes (Cain, 2012), MLA writes (Cain 24) with a page number and no comma, Harvard writes (Cain, 2012), and Chicago notes-bibliography puts a superscript number in the text that points to a footnote. Our complete guide to in-text citations covers those pairings in detail; the rest of this guide stays on the list itself.

APA 7: the References page

The Publication Manual of the American Psychological Association (7th ed.) sets out the page rules in Chapter 9. The list starts on a new page after the body text, under the heading References in bold, centered. The whole page is double-spaced, with no extra blank lines between entries, and every entry carries a 0.5-inch hanging indent: first line flush left, every following line indented.

Order is alphabetical by the first word of each entry, compared letter by letter (Section 9.44). Two refinements decide the cases that trip people up. Nothing precedes something, so Anders, Y. J. files before Anderson, E. L. And spaces and punctuation are ignored, so De Long files as "delong," after Dean. Several works by the same author sort chronologically, works with no date first and works in press last, and the author's name is repeated in full for every entry. APA has no dash convention for repeated names.

Those ordering rules run deeper than one paragraph can cover (same author and year, Mc and Mac surnames, titles that start with numbers). The worked cases live in our guide to APA reference list order.

MLA 9: the Works Cited page

The MLA Handbook (9th ed.) calls the list Works Cited, centered at the top of a new page in plain type: no bold, no italics, no quotation marks, same font and size as the paper. Double-space everything, use 1-inch margins, and give every entry the same 0.5-inch hanging indent APA uses.

The name of the page is a rule in itself. Works Cited lists the works you cited. A source you read for background and never cited belongs in a separately labeled list (Works Consulted) if your instructor wants one at all. Every entry on the page needs a matching in-text citation, and every in-text citation needs a matching entry.

Order is alphabetical by author, or by title when there is no author, ignoring an initial A, An, or The. When one author has several works, the works sort alphabetically by title, the first entry gets the author's name, and each later entry replaces the name with three hyphens and a period (---.). The three hyphens stand for exactly the same name, so a book Gladwell wrote alone and a book he co-wrote cannot share them. Page setup, sample pages, and a full checklist are in our guide to formatting a Works Cited page in MLA 9.

Chicago 18: the Bibliography

Chicago's notes-bibliography system pairs footnotes in the text with a Bibliography at the end, centered heading, new page, entries in alphabetical order with a 0.5-inch hanging indent (Chicago Manual of Style, 18th ed., Chapter 13). Turabian, the student version of Chicago, single-spaces each entry and puts a blank line between entries, which is the setting most course guidelines mean when they say "Chicago format." Departments differ on spacing, so a style sheet from your instructor outranks anything in this paragraph.

The 18th edition (2024) changed two things worth knowing even if you learned Chicago recently:

• Repeated authors. Earlier editions replaced a repeated author's name with a 3-em dash. The 18th edition prefers repeating the name (Section 13.113). You will still see the dashes in published books and older guides; new papers should repeat the name.
• Place of publication. Books published since 1900 no longer need a city before the publisher. "New York: Crown Publishers, 2012" becomes "Crown Publishers, 2012."

The bibliography entry is only half the system. The footnote for the same book reads differently (first name first, commas instead of periods, a page number), and shortened notes take over after the first citation. The full pairing is in our guide to Chicago notes-bibliography style. Chicago's other system, author-date, swaps the footnotes for (Cain 2012) citations and retitles the list "References."

Harvard: the reference list

Harvard is an umbrella term for a family of author-date styles, with no single governing manual. UK and Australian universities each publish their own variant, most based on Cite Them Right or an in-house guide such as Leeds Harvard. The core is stable across variants: the heading is Reference list, the order is alphabetical by first author's surname, and the year sits in parentheses after the author.

The page details are where variants disagree. Cite Them Right includes the place of publication; some university guides drop it. Most ask for a hanging indent, some for a blank line between entries instead. There is no wrong answer in the abstract, only your university's answer, so download your department's guide and match it exactly rather than following a generic Harvard example from the web. If the local guide is silent on a detail, pick the common form (hanging indent, place included) and apply it consistently. Note the naming: in most Harvard guides a reference list holds what you cited, and "bibliography" means a longer list that also includes background reading.

IEEE and Vancouver: numbered lists sort themselves

Two major styles skip alphabetical order entirely. IEEE (engineering and computer science) assigns each source a bracketed number, [1], [2], [3], in the order it first appears in the text, and the reference list at the end runs in citation order. Vancouver (medicine and health sciences) works the same way, with the numbers set as superscripts or brackets depending on the journal.

The formatting consequence: never alphabetize a numbered reference list. Sorting it A to Z breaks the link between every number in your text and the entry it points to, which silently miscredits every source in the paper. If a source is cited again later, it keeps its original number. The entry-level rules for each system are in our IEEE guide and Vancouver guide.

How to format references in Word and Google Docs

The three mechanical settings behind every well-formatted list are sorting, the hanging indent, and line spacing. All three should be applied to the finished list in one pass, since each is a paragraph setting that new text inherits unevenly.

Alphabetize. In Word, select the whole list and click the A-Z sort button on the Home tab, then OK. In Google Docs, install a sorting add-on or paste the list through a sorted column in Sheets. Then check the result by eye: a machine sort handles surnames well but knows nothing about APA's refinements, so same-author stacks (chronological, no-date first, in press last) and letter-suffixed years (2020a before 2020b) may need hand-fixing afterward.

Hanging indent. In Word, select the list and press Ctrl+T (Cmd+T on a Mac), or open the paragraph dialog and set Special to Hanging at 0.5". Google Docs hides the same setting under Format > Align & indent > Indentation options. Never build the indent out of Tab presses and manual line breaks; it collapses the moment an entry gets longer or shorter, and it exports badly. The step-by-step versions, including what to do when the shortcut does nothing, are in our guides for Word and Google Docs.

Spacing. For APA and MLA, select the list and set line spacing to 2.0 with no extra space between paragraphs. For a Turabian-style Chicago paper, set single spacing and add the blank line between entries.

Why your reference list looks inconsistent

"My citations are inconsistent" is one of the most common formatting complaints from students, and it almost never comes from ignorance of a rule. It comes from assembly. A typical reference list is built over weeks from different sources: two entries copied from a database's Cite button, three from a generator, one from a journal's own "cite this article" box, one written by hand, and lately several produced by an AI chatbot. Each source has its own defaults, and some have errors, so the list ends up speaking four dialects at once.

AI-formatted references deserve their own warning, because their errors are formatted well enough to look finished. A chatbot's output can carry the wrong capitalization or author order for the style you asked for, splice together rules from two different styles, attach a DOI that belongs to a different paper, or pair the right author with the wrong year. A generator that pulls metadata from the actual source can still inherit sloppy publisher metadata. Either way the fix is the same: check every entry against the source itself, and against one style guide, before you submit.

The efficient repair for an inconsistent list is an element-by-element audit rather than an entry-by-entry one. Read only the authors down the whole list and fix them, then only the years, then only the titles, then the punctuation. Scanning one element at a time makes a stray full first name or a title-cased APA article jump out in a way that rereading whole entries does not. The full audit procedure, with a checklist per style, is in our guide to fixing citation errors.

Common mistakes and how to avoid them

• Alphabetizing an IEEE or Vancouver list. Numbered styles run in citation order; sorting them breaks every citation in the text. If the numbers in your text no longer match your list, this is the first thing to check.
• Faking the hanging indent with tabs and manual line breaks. It survives until the first edit. Use Ctrl+T or the indentation dialog so the indent recalculates itself.
• Carrying one style's capitalization into another. The most common crossover is title-casing an article title in APA, because databases and publishers display titles in title case. APA and Harvard want sentence case; MLA and Chicago want title case.
• Titling the page from the wrong style. "Works Cited" on an APA paper or "References" on an MLA paper signals a template mismatch before the reader reaches a single entry. Match the title, and its formatting, to the style: References in bold for APA, Works Cited in plain type for MLA.
• Listing sources you never cited. In APA, MLA, and most Harvard variants, the list holds cited works only. Chicago is the exception whose bibliography may include background reading.
• Reordering authors within an entry to make sorting easier. Author order on the source records who contributed most, and every style preserves it. Alphabetization happens between entries only.
• Submitting machine-formatted entries unchecked. Generators and chatbots produce plausible formatting around wrong details. The entries most worth checking by hand are the ones you did not type.

Quick-reference table