writing style for research paper

How to Format a Research Paper: APA, MLA, and Chicago Styles

The rules for academic writing go beyond citing sources and using proper research methods. You also have to adhere to the right research paper format and the technical rules for structuring and writing your paper. The problem is the three main research paper formats—APA, MLA, and Chicago—all have different rules.

Below, we explain all the essential formatting guidelines you need to know when writing your research paper. We’ll cover the formatting guidelines for all three styles and even share some examples of academic citations so you can write yours to match.

Table of Contents

What is a research paper format?

Style guide comparison: which formatting guidelines to use, common rules for all research paper formats, apa style guide, mla style guide, chicago style guide.

A research paper format is a set of rules and style suggestions for writing in academic research. These formats each have their own preferences about how a paper should be, such as how to write in-text citations or structure the bibliography , and style choices like when to spell out numbers.

Although there are a few other styles, modern academic writing typically uses three main ones: APA, MLA, and Chicago.

The first step in how to write a research paper is choosing your format. It’s smart to know which style you’ll use for academic citations and writing choices before you begin; otherwise, you’ll have a lot more editing to do at the end.

Which format to use is generally related to the subject of the research paper. Professors may state which style they prefer for papers in their class, but this is not always the case. If you’re unsure of which style to use, here are the traditional guidelines for which subjects use which formats:

• APA: social sciences (psychology, sociology, anthropology, education, and some business topics)
• MLA: humanities (languages, philosophy, literature, religion, ethics, and the arts)
• Chicago: history and unique topics

While these styles have different preferences for paper structure and other formatting guidelines, the most distinct differences are in how they write academic citations.

You can see the differences yourself in our article on citation examples , which explains the differences in detail and how to create them yourself.

If you’re having trouble writing academic citations, use our free citation generator , which automatically creates citations for APA, MLA, and Chicago.

Before we get into the differences between these three research paper formats, let’s talk about what’s the same. Some rules are universal for academic writing, so you follow them no matter your format. Here are the key formatting guidelines every style adheres to:

• Double-spaced
• Paragraph indentations are 0.5 inches
• Printed on 8½-by-11-inch paper
• One-inch margin on all sides (except running heads)
• Use the Oxford comma , a.k.a. the serial comma.
• Spell out numbers that begin a sentence, heading, or title.
• Entries in the bibliography use a hanging indent (every line except the first is indented).

The APA format comes from the American Psychological Association, which explains its connection to the social sciences. Compared to other styles, the APA style guide emphasizes formality and clarity, in keeping with the association’s scientific orientation. Likewise, APA citations tend to value dates and years of publication.

APA paper structure

• Title page creation. Title pages, also called cover pages , are necessary in APA and must include the paper’s title and the names of each author. Student papers also require the school, course number, instructor name, and assignment due date on the title page, while professional papers need the authors’ affiliations and a note on the authors.
• Running head . Every page in APA requires a running head, which is a line of text at the top of the page. The running head for student papers has only the page number, flush right, but professional papers also include the paper’s title abbreviated to under 50 characters, flush left.
• Abstract . Although not always necessary, some APA papers include an abstract , a page that goes immediately after the title page and contains a brief summary of the paper in under 250 words. Place the title “Abstract” at the top of the page, centered and in bold, and use no indentation for the text. Abstracts can be written in paragraph style or categorized by Objective, Method , Results , and Conclusion .
• First page. In addition to the title page, the first page of text also has the paper’s title with title case capitalization, centered and in bold.

APA rules for style

• Formality . Do not use contractions or colloquialisms . Avoid using the editorial we in the sense of everyone . Instead, say something more specific, such as “people” or “the average person” or similar.
• Capitalization . Use title case capitalization for all headings, tables, and figure titles. However, for the titles of works in the reference list, use sentence capitalization (only capitalize the first letter of the first word).
• Fractions . Differing from other number rules, fractions are spelled out if they are simple and/or common ( one-third , a half ).
• numbers with units of measurement ( 9 in. )
• numbers in a series after a noun ( Chapter 4 )
• times and dates ( 4:17 p.m., 7/20/69 )
• ages ( 5 years old )
• scores and points ( 7–1 )
• money ( $3.50 )
• numbers themselves ( the number 8 )
• statistical or mathematical functions: ratios, decimals, percentages, etc. ( 10:1, 3 times as many )

APA citation formats

For in-text citations where the source information is not presented in the text, use parenthetical citations with the author’s last name and the year of publication , separated with a comma. If you are using a direct quote, you must also include the page number (with the abbreviation p. ), a timestamp, or another location indicator, also separated with a comma.

(Sobol, 2021)

(Sobol, 2021, p. 455)

APA bibliography formatting

Each source used in your paper requires a full citation in the bibliography, which in APA is referred to as the reference page . The reference page uses the title “References” centered and in bold at the top, and itself comes at the end of the research paper text, but before tables and appendices.

Generally, each source entry contains the full name of the author or authors (each should be listed with the last name first), title, date of publication, and sometimes the type of source.

Sobol, M., Przepiórka, A., Meisner, M., & Kuppens, P. (2021). Destiny or control of one’s future? Fatalistic time perspective and self-esteem in extroverts and introverts. The Journal of General Psychology, 149 (4), 443–455.

Each type of source has its own formula, so refer to our APA guide for how to write full citations for books, online articles, videos, etc.

The MLA format comes from the Modern Language Association and applies to research papers in the arts and humanities. The MLA style guide is one of the most used formats, in particular for high school and undergraduate students. Because it deals with human interest and artwork, MLA emphasizes creators and authorship in citations.

MLA paper structure

• Block quotes . Set direct quotations in block quotes if they are four lines or longer (with poetry, three lines or longer). Block quotes are indented 0.5 inches on each side and set apart from other text. Do not use quotation marks; place the parenthetical citation after the ending punctuation.
• Author’s name
• Instructor’s name
• Course number
• Running head . Each page must include a running head with the author’s last name and page number, flush right.

MLA rules for style

• Abbreviations . Do not use periods with abbreviations ( UK , not U.K. ).
• Numbers . If a number or fraction can be written in one or two words, spell it out ( ninety-nine , twenty million , one-fifth ). For other numbers, use numerals. Additionally, use numerals for items in a series ( Chapter 4 ) and when numbers are mixed or discussed frequently ( between 50 and 150 people ).
• Dates . Do not abbreviate dates. Use the full month-day-year or day-month-year format.
• Names . Use a person’s full name the first time they are mentioned, and only surname (last name) for subsequent mentions. Surnames include particles like de , O’ , or von .

MLA citation formats

In-text citations in MLA use parenthetical citations with the author’s last name and preferably also the page number , a timestamp, or another location indicator. Do not use commas or abbreviations for the page number.

MLA bibliography formatting

In MLA, the bibliography is called the works cited page . It comes at the end of the paper with the title “Works Cited” centered at the top. Entries are organized alphabetically by the first word, usually the author’s last name.

Camus, Albert. The Myth of Sisyphus and Other Essays. Translated by Justin O’Brien, New York, Random House, 1955.

You can read about the specific details for formatting a works cited page in our guide here . To learn how to write full citations in MLA, see our MLA guide .

The Chicago format is a little different from APA and MLA because it encourages personalization. Rather than offering a specific way of formatting your paper, Chicago offers rules for a few different methods, which allows the author to choose the most apt one for them.

This flexibility is most evident in the choice between two citation systems: Author-Date and Notes-Bibliography . The Author-Date system follows similar guidelines to the parenthetical citations in APA and MLA, while the Notes-Bibliography system utilizes footnotes or endnotes to reference sources, rather than interrupting the text.

Chicago paper structure

• Page numbers . Each page should include a page number, either in the top right or bottom center.
• Block quotes. Use block quotes for direct quotations five lines or longer. Indent each line 0.5 inches, and do not use quotation marks.
• Capitalization . Headings are capitalized using the title case.

Chicago rules for style

• Abbreviations . Use periods for abbreviations that end in lowercase letters and initials in names (unless the entire name is initialized, like MLK ). Do not use periods for abbreviations with all capital letters.
• numbers with symbols or measurements ( 3 km )
• percentages ( 7% )
• decimals ( 0.333 )

Chicago citation formats

Author-date:

Chicago’s author-date system for academic citations follows similar rules as the APA and MLA style guides. It uses a parenthetical citation with the author’s last name and the year of publication , as well as an optional location indicator like a page number with no abbreviation. The author’s name and year of publication are not separated by a comma, but the page number or other location is.

(Maalouf 1984)

(Maalouf 1984, 215)

Notes-bibliography:

As an alternative to the author-date system, you can instead use the notes-bibliography system, which utilizes footnotes (bottom of the page) and endnotes (end of the chapter or section). This is advisable if you use a lot of citations so that they do not disrupt the reading flow with constant interruptions.

Both footnotes and endnotes are marked in-text with a superscript number corresponding to the same number in the note section. If you include a bibliography at the end of the paper, your notes use a short form , which only covers the basic information like the author’s name, an abbreviated title, and page number.

1. Maalouf, Crusades , 210.

If you are not including a bibliography, you must include the full citation in the first note that references the source.

1. Amin Maalouf, The Crusades through Arab Eyes. London: Al Saqi Books, 1984.

However, all references to the same source after the first can use the short form.

Chicago bibliography formatting

The bibliography in Chicago is understandably flexible. In fact, even the title at the top changes: “Bibliography” for the notes-bibliography system and “References” or “Works Cited” for the author-date system.

In terms of formatting, names are inverted so that the surname comes first, and titles are capitalized in the title case.

Maalouf, Amin. 1984. The Crusades through Arab Eyes . London: Al Saqi Books.

For details on how to cite specific types of sources, see our Chicago guide .

Key takeaways

• Most research papers use either the APA, MLA, or Chicago format, depending on the subject or the professor’s preference. In general, APA is for social sciences, MLA is for arts and humanities, and Chicago is for history and unique subjects.
• Each style has its own rules for how to format papers, such as when to spell out numbers, and how to write academic citations.
• You can see the basics for each format above, or read more in-depth instructions in our dedicated guides: APA , MLA , or Chicago .
• To help with academic citations, use our free citation generator , which creates citations automatically for all three styles.

Research paper format FAQs

What are the differences between apa, mla, and chicago reference styles.

The three main research paper formats—APA, MLA, and Chicago—all have their own rules for paper structure and academic citations. Aside from the preferences of the course professor, the formats are generally categorized by subject: APA for social sciences, MLA for arts and humanities, and Chicago for history and unique subjects.

Can I use more than one citation style in my research paper?

No, you must use only one research paper format consistently. Each style has overlapping rules that contradict each other, so keep to only one at a time.

What are some common mistakes to avoid in research paper formatting?

Be sure to check the formatting guidelines on how to identify each type of source. Citing a book uses a different format than citing an online article, even if you’re using the same style guide.