IEEE Style Guide: A Complete Overview of Formatting Rules for Research Papers

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June 30, 2026
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Key Takeaways

IEEE style uses four distinct heading levels, each with its own capitalization, numbering, and indentation rules; getting these consistent matters as much as the content itself.
The first footnote on page one is unique to IEEE style and must contain submission dates, funding information, author affiliations, and the DOI, all without a footnote number.
Numbers, equations, and units follow precise formatting conventions, including thin spaces for digit grouping, italicized variables, and multidots for compound units.
Lists in IEEE manuscripts follow a fixed three tier numbering pattern: 1), 2), 3), then a), b), c), then i), ii), iii).

Contents

What Is IEEE Style?
IEEE Style Title Formatting Rules
What Goes in the First Footnote of an IEEE Paper?
Formatting the Abstract and Index Terms
How Are Section Headings Structured in IEEE Style?
Formatting Equations in IEEE Style
Footnote Numbering and Placement Rules
How Do You Number Lists in IEEE Style?
Formatting Numbers and Mathematical Data
Citations in IEEE Style
References in IEEE Style
Common IEEE Formatting Mistakes to Avoid
IEEE Style Compared with APA and MLA
Frequently Asked Questions about IEEE Style

What Is IEEE Style?

IEEE style is a formatting and citation system created by the Institute of Electrical and Electronics Engineers for technical and scientific writing, primarily in engineering, computer science, and physics. It governs everything from title capitalization to equation numbering.

IEEE is the world’s largest technical professional association, made up of more than 35 technical societies and councils active in over 300 countries. The organization maintains seven offices worldwide and is associated with more than 2,000 conferences a year; IEEE Day is celebrated globally every October 1.

IEEE publishes a large number of high-quality journals, transactions, and conference proceedings, and its style guide is one of the most widely used formatting standards in the physical sciences. Researchers submitting to IEEE venues are expected to follow it precisely, since formatting errors can slow down peer review and editorial processing.

IEEE Style Title Formatting Rules

Article titles in IEEE style follow a specific capitalization pattern rather than standard sentence or title case rules used elsewhere.

The first and last words of the title are always capitalized, regardless of their part of speech.
All nouns, pronouns, verbs, adjectives, and adverbs are capitalized.
Long prepositions, such as before, between, and through, are capitalized.
Long conjunctions, such as because and although, are capitalized.
Short prepositions and conjunctions, such as in, of, and, and the, are generally left lowercase unless they begin or end the title.

This rule set differs from APA and Chicago title case in subtle ways, so it is worth checking your title against these rules even if you are confident with other style guides.

What Goes in the First Footnote of an IEEE Paper?

The first footnote of an IEEE paper contains three unnumbered paragraphs covering submission dates and funding, author affiliations, and the DOI; it is the only footnote in the paper that is never numbered.

This is one of the clearest differences between IEEE style and other common style guides such as AMA and APA, which do not use this kind of structured opening footnote. The three paragraphs are organized as follows:

Paragraph	Content	Formatting Notes
Paragraph 1	Received and revised dates of the paper; all financial support or funding for the research	No footnote number is used anywhere in this footnote
Paragraph 2	Author affiliations, with each author starting a new paragraph	Names are presented as initials plus surname; authors sharing an affiliation can be grouped together
Paragraph 3	The DOI assigned by IEEE to the published article	Added once the DOI is issued, typically at the production stage

Formatting the Abstract and Index Terms

The abstract of an IEEE paper is presented in boldface text and should not contain references or mathematical equations, since it needs to stand alone for indexing and search purposes.

Index Terms appear directly after the abstract and serve the same purpose as keywords in other style guides. IEEE authors have a useful resource here: they can request a list of IEEE approved keywords by emailing the IEEE keywords mailbox directly, which helps ensure the terms used match the organization’s indexing system.

The main text of an IEEE paper is set in two columns using 10 point Times New Roman font. Times New Roman is also the required font for all headings, which is covered in detail in the next section.

How Are Section Headings Structured in IEEE Style?

IEEE style uses four heading levels, each with a distinct capitalization style, numbering format, and placement on the page, ranging from fully capitalized centered headings down to run in subheadings.

Level	Capitalization	Numbering	Placement
Level 1	All capitals	Roman numeral (I, II, III)	Centered
Level 2	Significant words capitalized	Capital letter and period (A., B.)	Flush left
Level 3	Significant words capitalized, italicized	Arabic numeral and parenthesis	Indented one em space, run into text, followed by a colon
Level 4	First word and proper nouns only	Lowercase letter	Indented two em spaces, run into text, followed by a colon

References, Appendix, and Acknowledgment headings are never numbered, but they otherwise follow Level 1 formatting rules. Appendixes can be labeled Appendix I, Appendix II, and so on, or alternatively Appendix A, Appendix B; if a paper has only one appendix, simply label it Appendix.

Formatting Equations in IEEE Style

Equations in IEEE papers are usually numbered consecutively throughout the manuscript, though some IEEE journals permit numbering by section instead, such as (1.1) or (2.1).

Place the equation number in parentheses, flush with the right margin of the column.
Refer to equations by number in the text rather than repeating the full expression.
Keep equation numbering consistent throughout the entire manuscript, including any appendixes.

Footnote Numbering and Placement Rules

Aside from the unnumbered first footnote described earlier, every other footnote in an IEEE paper must be numbered consecutively using superscript Arabic numbers.

Place footnote numbers after periods, commas, and parentheses.
Place footnote numbers before colons, dashes, semicolons, or quotation marks.
Position footnotes at the bottom of the column where the reference occurs, not at the bottom of the page or the end of the document.

One practical tip: be careful when a footnote number falls close to an equation or numerical data, since a superscript number can be mistaken for an exponent. If this risk exists, reword the sentence to separate the two.

How Do You Number Lists in IEEE Style?

IEEE style numbers lists in three tiers: first with 1), 2), 3); then with a), b), c) for sub items; then with i), ii), iii) for any further nested items within those.

For example, a sentence might read: favorite summer activities are 1) hiking a local trail, 2) reading outdoors, and 3) running small experiments using a) basic household items, b) a notebook for observations, and c) a simple data log.

This tiered numbering applies specifically to lists embedded in the main text, not to numbered references or numbered equations, which follow their own separate conventions described elsewhere in this guide.

Formatting Numbers and Mathematical Data

Because precise number presentation matters so much in engineering and the physical sciences, the IEEE style guide devotes an entire section to formatting numbers, variables, and units correctly.

Use a thin space instead of a comma in numbers such as 10 000; in Microsoft Word, this is created using the quarter em space option under Special Characters in the Insert menu.
Always add a zero before a decimal point, so a value is written as 0.5 rather than .5.
Italicize variables, and use bold italics for vectors and matrices.
Spell out the word Equation only when it starts a sentence; in the middle of a sentence, use just the number, for example, this condition is not fulfilled in (3).
If an equation concludes a sentence, end it with a period, just as you would any other sentence.
Use a multidot, such as V·s, to join compound units rather than a space or hyphen.

Citations in IEEE Style

IEEE uses a numbered, bracketed citation system: each source gets a number in square brackets, such as [1], based on the order in which it first appears in the text, not alphabetically by author.

Place the bracketed number directly after the relevant text, before any punctuation in most cases, for example, “as shown in [3].”
Reuse the same number every time you cite that same source again later in the paper; do not assign it a new number.
For multiple sources cited together, separate the numbers with commas, such as [2], [5], [9], or use a range with a dash for consecutive sources, such as [4] to [7].
You can also cite a source as part of a sentence, such as “the results in [6] confirm this trend,” rather than only at the end of a sentence.
Page numbers are not typically required in the in text citation itself; if needed for a direct quotation, they can be added inside the brackets, such as [8, p. 12].

This numbered approach is one of the biggest differences between IEEE style and author-date systems like APA, since readers must check the numbered reference list to identify the actual source rather than seeing the author name in the text itself.

References in IEEE Style

The reference list in IEEE style appears at the end of the paper under the heading References, follows Level 1 heading rules, and is never numbered as a section itself; the entries inside it, however, are listed in numerical order matching their first citation in the text.

List references in the order they were first cited in the text, not alphabetically by author surname.
Number each entry to match its in-text citation number, formatted as [1], [2], and so on, flush left at the start of the entry.
Use author initials followed by surname, rather than full first names, for each listed author.
Include the title of the article in quotation marks and the title of the journal or publication in italics.
Provide volume, issue, page range, and year of publication for journal articles; for conference papers, include the conference name and location.
Abbreviate journal titles using standard IEEE abbreviations where they exist, rather than spelling out the full publication name.
For online sources, include the DOI when available instead of a full URL where possible.

Because every in-text citation number must correspond exactly to its reference list entry, double-checking that the numbering stays aligned after any edits is one of the most important final checks before submission.

Sample References in IEEE Style

Source Type	Sample IEEE Reference
Journal Article	[1] A. B. Smith and C. D. Jones, “Deep learning approaches for signal classification,” IEEE Trans. Signal Process., vol. 68, no. 4, pp. 1023-1035, Apr. 2020.
Book	[2] R. K. Patel, Principles of Digital Communication, 3rd ed. New York, NY, USA: Wiley, 2019.
Book Chapter	[3] M. L. Chen, “Wireless sensor network architectures,” in Advances in Embedded Systems, J. R. Lee, Ed. Boston, MA, USA: Springer, 2018, pp. 145-167.
Conference Paper	[4] S. T. Nguyen and P. A. Ortiz, “Energy efficient routing for IoT networks,” in Proc. IEEE Int. Conf. Commun. (ICC), Dublin, Ireland, 2021, pp. 1-6.
Published Dissertation	[5] E. W. Park, “Adaptive control strategies for robotic manipulators,” Ph.D. dissertation, Dept. Elect. Eng., Stanford Univ., Stanford, CA, USA, 2022.
Preprint	[6] H. J. Müller and L. F. Costa, “Transformer based models for time series forecasting,” arXiv:2301.04567, 2023.
Patent	[7] D. N. Walsh, “Method and apparatus for low power signal transmission,” U.S. Patent 10 987 654, Jan. 12, 2021.

Common IEEE Formatting Mistakes to Avoid

Treating the first footnote like a numbered reference instead of leaving it unnumbered.
Using commas instead of thin spaces in long numbers.
Skipping italics for variables in equations or in the body text.
Mixing up the heading levels, such as using Level 2 capitalization rules on a Level 1 heading.
Forgetting to add Index Terms directly after the abstract.
Numbering footnotes out of order or placing them at the bottom of the wrong column.

IEEE Style Compared with APA and MLA

IEEE style differs from APA and MLA in several structural ways, particularly in how it handles citations, headings, and the first page of a manuscript.

Feature	IEEE Style	APA Style	MLA Style
Citation format	Numbered, in brackets	Author and date	Author and page number
Reference list order	Order of first citation	Alphabetical	Alphabetical
Abstract formatting	Boldface, no references	Plain text, separate page	Not typically required
First page footnote	Required, unnumbered, three paragraphs	Not used	Not used

Frequently Asked Questions about IEEE Style

What font and font size does IEEE style require?

IEEE style requires Times New Roman font throughout the manuscript, including the main text and all heading levels. The main body text is typically set in 10 point type within a two column layout.

How do you cite sources in IEEE style?

IEEE uses numbered, bracketed in text citations, such as [1] or [2], that correspond to a numbered reference list ordered by first appearance in the text rather than alphabetically. Each unique source keeps the same number throughout the paper.

Does IEEE style use a separate title page?

Most IEEE journals do not require a separate title page; the title, authors, and affiliations appear at the top of the first page, followed directly by the abstract, Index Terms, and the unnumbered first footnote.

How many heading levels does IEEE style allow?

IEEE style defines four heading levels, each with its own capitalization, numbering, and indentation pattern, ranging from fully capitalized centered Level 1 headings to run in Level 4 subheadings.

What is the correct way to format an abstract in IEEE style?

An IEEE abstract must be written in boldface and must not include references or mathematical equations, since it is meant to function as a self contained summary for indexing and search engines.

Can you use commas in large numbers under IEEE style?

No, IEEE style replaces commas in large numbers with a thin space, so a number such as 10,000 is written as 10 000 using the quarter em space character available in most word processors.

How do you label multiple appendixes in an IEEE paper?

Multiple appendixes are labeled either as Appendix I, Appendix II, and so on, or as Appendix A, Appendix B, and so on; if a manuscript has only a single appendix, it is simply labeled Appendix.

Where should footnotes be placed in an IEEE manuscript?

Footnotes belong at the bottom of the column in which the reference mark appears, not at the bottom of the full page or at the end of the document, and every footnote except the first must carry a superscript number.

This article was originally published on August 8, 2024, and updated on June 30, 2026.

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