My sophomore year, I handed in what I thought was a solid research paper. My professor handed it back with three words circled in red at the top: wrong citation style. I had used MLA for a psychology class. The content was fine. The format sank me.
That moment taught me something no syllabus spells out clearly: essay formatting rules aren’t optional extras. They’re the language each academic discipline speaks. Mess up APA, MLA, or Chicago, and you’re not just losing points — you’re showing you don’t understand the field’s conventions. Here’s what I’ve learned using all three styles across years of academic and professional writing.
Why These Three Styles Exist — and Why It Matters Which One You Use
When I first encountered all three formats in the same semester, I thought they were interchangeable with minor tweaks. They’re not. Each one was built around what a specific academic community values most.
APA (American Psychological Association) prioritises the date. In science and education, research ages fast. A 2009 study on social media behaviour is practically prehistoric. So APA puts the year front and center in every citation — it’s the first thing a reader sees.
MLA (Modern Language Association) prioritises the author. In the humanities, you’re engaging with someone’s interpretation, and the person behind the argument matters. That’s why MLA leads with the name.
Chicago style, which I use most in my writing work now, was built for historians and publishers. Its footnote system keeps citations out of the prose so the writing breathes — you can chase a source at the bottom of the page without losing the thread of the argument.
Once I understood the logic, the rules stopped feeling arbitrary.
APA Formatting Rules (7th Edition)
Title Page and Running Head
APA requires a full title page: your paper’s title in bold and centered, followed by your name, institution, course, instructor, and submission date. For student papers, the header only needs a page number.
If you’re submitting a professional manuscript, you also need a running head — a shortened title in ALL CAPS, under 50 characters, on the left side of every page header.
I’ve seen students skip the running head on professional papers because they assumed the student version applied to everything. It doesn’t.
Abstract
Most APA papers include an Abstract — a 150 to 250 word standalone summary that lives on page two, before your body text begins. The mistake I made early on was treating it like an introduction. It isn’t.
An abstract is a compressed version of your entire paper: the research question, the method, the finding, and the implication. Write it last, even though it appears first.
Citations and References
In-text: (Author, Year). With a direct quote: (Smith, 2023, p. 14).
Your final page is titled References. For a website, the entry looks like:
Smith, J. (2023, May 15). Climate change facts. NASA.
The webpage title is italicised. The site name (NASA) is not. That specific distinction used to trip me up constantly before I committed it to memory.
MLA Formatting Rules (9th Edition)
Header Instead of Title Page
MLA skips the title page for standard essays. Instead, a four-line block sits at the top-left of your first page: your name, instructor’s name, course name, and date. Your essay title is centered on the line right below — no bold, no italics, no underlining. Just your words.
Some instructors request a title page anyway. I always check the assignment sheet before I assume.
Page Numbers
Every page gets your last name and the page number in the top-right header — e.g., Smith 4. Set it in your word processor’s header tool so it auto-populates. Don’t type it manually on each page.
Citations and Works Cited
In-text: (Author Page#). No comma, no year. For a website with no page numbers: just (Smith).
The final list is Works Cited. For a website:
Smith, John. “Climate Change Facts.” NASA, 15 May 2023,
The website name is italicised — MLA calls it the “container.” The article title goes in quotation marks. Note the date format: day-month-year, not month-day-year like in APA. Small difference, real consequence if your professor notices.
Chicago Formatting Rules (17th Edition)
Two Systems — Pick the Right One
Chicago gives you two options.
Notes and Bibliography is for humanities — history, literature, fine arts.
Author-Date is for sciences and social sciences and functions a lot like APA. If you’re in a humanities course and your instructor says “Chicago,” they almost certainly mean Notes and Bibliography.
Title Page
Chicago requires a separate title page. The title is centered about one-third down the page. Your name, course, and date go near the bottom. The title page is unnumbered — your body text begins at page 1.
Footnotes and Bibliography
This is where Chicago feels genuinely different. Instead of parenthetical citations interrupting your prose, you drop a superscript number at the end of the sentence. That number connects to a footnote at the bottom of the page.
A website footnote looks like:
¹ John Smith, “Climate Change Facts,” NASA, May 15, 2023,
The bibliography entry at the end of the paper inverts the name:
Smith, John. “Climate Change Facts.” NASA. May 15, 2023.
The first time I wrote a Chicago paper, I listed footnotes and bibliography entries identically. They’re not. Footnotes use natural name order (First Last). The bibliography flips it (Last, First). One structural difference, marked wrong.
Quick Comparison: APA vs MLA vs Chicago
| Feature | APA (7th Ed.) | MLA (9th Ed.) | Chicago (N&B) |
| Title Page | Required | Not standard | Required |
| In-Text Citation | (Author, Year) | (Author Page#) | Superscript number |
| Final List Name | References | Works Cited | Bibliography |
| Date Format | Year, Month Day | Day Month Year | Month Day, Year |
| Best For | Sciences, Education | Humanities | History, Fine Arts |
What to Do When There’s No Author
All three styles handle this the same way: move the page title into the author position.
In APA specifically, if the page belongs to a corporate or government organisation, you can use the org name as the author. A NASA page with no byline cites as (NASA, 2023) in-text, and the reference list entry starts with “NASA.”
In MLA and Chicago, the page title leads, formatted according to that style’s rules.
The Error That Actually Hurts Your Grade
The most damaging mistake isn’t a misplaced comma. It’s using the wrong format for the wrong discipline — submitting MLA to a science professor or APA to a history department. I’ve done both, early on.
Professors in specialised fields recognise their citation conventions the way you’d recognise your own handwriting. A mismatch reads as unfamiliarity with the field, not just a formatting slip. Ask your instructor at the start of the semester. Do not assume.
Once your citations and structure are solid, your conclusion deserves the same care. Knowing how to conclude an essay effectively keeps your argument landing — not just trailing off.
Format Right, Then Get Out of Your Own Way
Formatting is not the point of your essay. Your argument is. But a correctly formatted paper removes friction — it lets your reader focus on what you’re saying instead of what you got wrong on the cover page.
Print this guide. Check the comparison table before you start each new paper. And if you’re juggling multiple styles across different courses this semester, label your document templates. Future you will be grateful.
FAQs: Essay Formatting Rules
1. What is the difference between APA and MLA formatting?
APA is standard in sciences and leads citations with the year. MLA is used in humanities and leads with the author’s name. They differ in title page requirements, in-text citation format, and how the final source list is structured and named.
2. Do I always need a title page?
APA and Chicago require one. Standard MLA does not — it uses a four-line header at the top of the first page instead. Always confirm with your instructor before assuming either way.
3. What font and spacing should I use?
All three styles default to 12-point Times New Roman, double-spaced, with one-inch margins. APA 7th edition also accepts Calibri 11pt and Georgia 11pt for student papers.
