If you’re sitting in front of a blank document wondering whether to use APA, MLA, Chicago, IEEE, or ICONTEC citation style, you’re not alone. Thousands of students face this confusion every semester—and it shouldn’t be this complicated.
Here’s the good news: this guide will clear it up in 5 minutes. We’ll show you exactly which citation style you need, why it matters, and how to use it correctly. Better yet, we’ll show you the same source cited in all five styles so you can see the differences side-by-side.
Unlike surface-level comparison articles that just say «APA uses author-date,» we go deep with practical examples and include IEEE and ICONTEC—standards most other sites ignore entirely.
The Quick Decision Flowchart: Find Your Style in 30 Seconds
Before diving into the technical details, let’s answer the most important question: Which style do you actually need?
Is your paper in Psychology, Education, Nursing, or Social Sciences?
→ Use APA (American Psychological Association). This is the dominant standard in social and behavioral sciences.
Are you studying Humanities, Literature, Languages, or Cultural Studies?
→ Use MLA (Modern Language Association). Nearly universal in English departments and language studies.
Is your focus History, Arts, or certain Social Sciences?
→ Use Chicago (Chicago Manual of Style). Historians love Chicago for its flexibility with notes and bibliography systems.
Are you writing in Engineering, Computer Science, or Electrical Engineering?
→ Use IEEE (Institute of Electrical and Electronics Engineers). The technical standard for STEM fields.
Are you a Colombian student at a university requiring the national standard?
→ Use ICONTEC NTC 5613 (Instituto Colombiano de Normas Técnicas). Colombia’s official citation and formatting standard.
The Big Comparison Table: All 5 Styles at a Glance
| Feature | APA 7th | MLA 9th | Chicago 17th | IEEE | ICONTEC |
|---|---|---|---|---|---|
| In-text Citation | (Author, Year) | (Author Page) | Superscript¹ | [#] | Superscript or (Author, Year) |
| Reference List | References | Works Cited | Bibliography | References | Referencias Bibliográficas |
| List Order | Alphabetical | Alphabetical | Alphabetical | By citation order | Alphabetical |
| Title Page | Required | Not required | Optional | Not typical | Required |
| Running Head | Required (50 char max) | No | No | No | Sometimes |
| Font | 12pt serif preferred | 12pt readable | 12pt readable | 10pt Times New Roman | 12pt Times New Roman |
| Line Spacing | Double | Double | Double | Single or double | Double |
| Margins | 1 inch all sides | 1 inch all sides | 1 inch all sides | 1 inch all sides | 2.5cm all sides |
| Abstract | Required for research | Not used | Not used | Often required | Optional |
APA 7th Edition: The Social Science Standard
APA (American Psychological Association) is the citation style of choice for psychology, education, nursing, social work, and most social sciences. The 7th edition introduced several modernizations including more font flexibility and inclusive language guidelines.
What makes APA unique: Its author-date format makes it easy to see how current a source is—critical in fields where research moves fast. You’ll recognize APA by its (Author, Year) in-text citations, alphabetically-ordered References page, mandatory title page, and running head.
MLA 9th Edition: The Humanities Standard
MLA (Modern Language Association) dominates English departments, literature programs, and language studies worldwide. The 9th edition simplified many rules from earlier versions.
What makes MLA unique: Its simplicity and flexibility. The (Author Page) in-text citation is straightforward, and MLA doesn’t require running heads or abstracts. You’ll recognize MLA by its minimal header (name, professor, course, date), parenthetical author-page citations, and Works Cited page.
Chicago 17th Edition: The Historian’s Choice
Chicago offers two systems: Notes-Bibliography (preferred by historians) and Author-Date (similar to APA). The 17th edition remains the gold standard for historical research.
What makes Chicago unique: Its sophisticated notes system. Instead of parenthetical citations, Chicago uses superscript numbers that link to footnotes or endnotes with full citations. This allows explanatory notes alongside citations—crucial for historical work where you need to explain a source’s significance.
IEEE Style: The Engineering Standard
IEEE (Institute of Electrical and Electronics Engineers) is the citation system for electrical engineering, computer science, and most technical fields.
What makes IEEE unique: Its numbered citation system. Instead of citing by author name, IEEE uses [1], [2], [3] with a sequentially-numbered References list ordered by citation appearance, not alphabetically. This was designed for technical papers where readers care more about information sequence than author identity. For a comprehensive guide, see our IEEE Citation Format Guide.
ICONTEC NTC 5613: Colombia’s National Standard
ICONTEC (Instituto Colombiano de Normas Técnicas y Certificación) is Colombia’s official standards body. NTC 5613 is the national standard for bibliographic references and citations, required by many Colombian universities.
What makes ICONTEC unique: It’s designed specifically for Colombian academic contexts while incorporating elements from international standards. ICONTEC requires wider margins (2.5cm), mandatory title pages, and strict formatting rules. The reference page is titled «Referencias Bibliográficas.» For a full guide, see our hub de Normas ICONTEC.
The Same Source in 5 Styles: See the Differences
Here’s how to cite the same book in all five styles:
Thinking, Fast and Slow by Daniel Kahneman (2011, Farrar, Straus and Giroux)
APA 7th:
In-text: (Kahneman, 2011, p. 45)
Reference: Kahneman, D. (2011). Thinking, fast and slow. Farrar, Straus and Giroux.
MLA 9th:
In-text: (Kahneman 45)
Works Cited: Kahneman, Daniel. Thinking, Fast and Slow. Farrar, Straus and Giroux, 2011.
Chicago 17th (N-B):
In-text: ¹
Note: 1. Daniel Kahneman, Thinking, Fast and Slow (New York: Farrar, Straus and Giroux, 2011), 45.
Bibliography: Kahneman, Daniel. Thinking, Fast and Slow. New York: Farrar, Straus and Giroux, 2011.
IEEE:
In-text: [1]
Reference: [1] D. Kahneman, Thinking, fast and slow. Farrar, Straus and Giroux, 2011.
ICONTEC NTC 5613:
In-text: ¹ o (Kahneman, 2011)
Referencia: KAHNEMAN, Daniel. Thinking, fast and slow. New York: Farrar, Straus and Giroux, 2011.
Which Style for Your Field? Complete Guide
| Field of Study | Style | Why? |
|---|---|---|
| Psychology, Education, Nursing | APA | Emphasizes recent research via publication dates |
| English, Literature, Languages | MLA | Flexible formatting for writing-focused disciplines |
| History, Arts, Music, Theology | Chicago | Footnotes allow nuanced source discussion |
| Engineering, CS, Telecom | IEEE | Numbered system suits technical papers |
| Business, Economics | APA (or varies) | Growing standard in business research |
| Physics, Chemistry, Biology | IEEE or varies | IEEE common in research journals |
| Colombian Universities | ICONTEC (or APA) | National standard; APA increasingly accepted |
Common Confusion Points: Myths Debunked
«Bibliography,» «Works Cited,» and «References» Mean the Same Thing
The truth: They’re slightly different. References (APA, IEEE) and Works Cited (MLA) list only sources you cited. Bibliography (Chicago) can include sources consulted but not cited. Use the correct term for your style.
IEEE Numbers Are Assigned Randomly
The truth: IEEE numbers follow the order sources appear in your paper. The first source cited is [1], the second is [2]. Your References list is organized numerically, not alphabetically—fundamentally different from APA/MLA/Chicago.
MLA and APA Papers Look Completely Different
The truth: Both use double spacing, 1-inch margins, and 12pt fonts. The real differences are in citation format and running head requirements. Your documents look nearly identical; citations and reference pages are what differ.
Chicago Requires Footnotes (Not Endnotes)
The truth: Chicago accepts both. Footnotes appear at the bottom of the page; endnotes at the end. The choice is up to your professor—just be consistent.
Free Citation Tools
- Our Free Citation Generator — Supports APA, IEEE, and ICONTEC. Paste source details, get formatted citations.
- Zotero (Free) — Browser extension that captures and formats citations in any style.
- Mendeley (Free) — Organize research and auto-generate reference lists.
- Google Scholar — Click «Cite» under any result for quick citations (verify formatting).
Download Templates for Every Style
- APA Format Template — Free Download
- MLA Format Template — Free Download
- Chicago Style Template — Free Download
- IEEE Format Template — Free Download
- IEEE Citation Format Guide: Examples & Rules