Writing
How long is an abstract? Word limits for APA, journals, theses and conferences
Most abstracts are 150 to 350 words, and the limit belongs to whoever receives the paper. APA Style (7th edition) says to limit an abstract to 250 words; IEEE journals allow up to 250, PLOS ONE 300 and JAMA 350 for original research. University thesis rules run from 150 to 600 words, and many conferences count characters instead.
Abstract limits, quoted from each source
An abstract is as long as the journal, university or conference receiving it says, and the published limits run from 150 words to 600. The tables below quote each rule from the source's own page, as read on 4 November 2026. Journals and style guides first:
| Source | Limit | Counted in | What else the rule says |
|---|---|---|---|
| APA Style, 7th edition | 250 words | Words | "Limit your abstract to 250 words"; one paragraph; three to five keywords |
| Nature, Articles | Ideally 200 words; up to 300 if the editor agrees | Words | "Fully referenced summary paragraph", unlike most abstracts |
| PLOS ONE | 300 words | Words | "Do not include citations in abstracts" |
| IEEE journals | Up to 250 words | Words | Single paragraph; no abbreviations, footnotes, references or equations |
| JAMA, reports of original data | 350 words | Words | Structured, under up to ten set headings |
| JAMA, systematic review | 350 words | Words | Five headings, Importance to Conclusions and Relevance |
| JAMA, narrative review | 400 words | Words | Three headings: Importance, Observations, Conclusions and Relevance |
University thesis rules vary more than journal rules, though the ranking pages give a single "150 to 350 words" without naming one university:
| University | Limit | Source |
|---|---|---|
| North Dakota State University, master's thesis | 150 words | Disquisition formatting requirements |
| University of Warwick, research degrees | 300 words | Guide to examinations for higher degrees by research, 2.9 |
| Newcastle University, research degrees | 300 words | Rules for the form of theses, 2026-27 |
| North Dakota State University, doctoral dissertation | 350 words | Same page as above |
| MIT | Generally 500 words, single-spaced | Specifications for Thesis Preparation |
| University of Cambridge, Social Anthropology PhD | About 500 words | PhD style guidelines |
| NC State University | 600 words | ETD guide: abstract |
The author pages of NEJM, Science, The Lancet, PNAS, Cell and The BMJ refused every request when we checked, so this guide gives no figure for them rather than repeat one we could not read. The NEJM "250 words" that ranking pages print, for one, is not linked to an NEJM page on any of them.
APA's 250 words is a ceiling, not a range
The 7th edition of APA Style sets a maximum of 250 words and no minimum. APA's Abstract and Keywords Guide says "Limit your abstract to 250 words", and its footnote adds that "in academic journals, abstracts typically are limited to no more than 250 words. However, some instructors or journals have different abstract length and formatting requirements." The "150 to 250 words" that several ranking pages give as APA's rule does not appear in that guide.
The same guide says what fills the 250 words, at "usually 1–2 sentences per topic":
- key aspects of the literature review;
- the problem under investigation or the research questions;
- the hypothesis or hypotheses;
- the methods, with the study design, sample and sample size;
- the results;
- the implications.
Six topics at one or two sentences each gives an abstract of six to twelve sentences. The format is fixed too: the label Abstract, bold and centred, on the first line of page 2; the text one line below it as a single paragraph, not indented, double-spaced; then three to five keywords one line below the abstract, after the italic, indented label Keywords:.
Most student papers do not need one. The guide opens with a note that abstracts and keywords "are not typically required for student papers", and that students should ask their instructor or institution. An APA student paper with no abstract is not missing anything.
Journal abstracts: what the limit includes
Journal limits sit between 200 and 400 words, and the details beside the number matter as much as the number. Three differences change how an abstract is written:
- References. Nature's formatting guide asks for "a fully referenced summary paragraph, ideally of no more than 200 words". PLOS ONE says the opposite: "Do not include citations in abstracts." IEEE forbids references, footnotes, abbreviations and equations.
- Structure. JAMA's instructions for authors say "reports of original data should include an abstract of no more than 350 words using the headings listed below": Importance, Objective, Design, Setting, Participants, Interventions or Exposures, Main Outcomes and Measures, Results, Conclusions and Relevance, and Trial Registration for trials. IEEE, by contrast, asks for "a single paragraph up to 250 words".
- Flexibility. Nature's limit is "ideally" 200 words. Its annotated summary paragraph says two or three sentences of broader perspective may be added "if the editor considers that the accessibility of the paper is significantly enhanced", and then "the length of the paragraph can be up to 300 words". Its own example is 190 words without that part and 250 with it.
Is the abstract part of the word count?
Some journals count it and some do not, and the length rule says which. JAMA's original investigations are limited to "3000 words of text (not including abstract, tables, figures...)". Nature counts it in: a six-page article with four modest display items is typically "2500 words (summary paragraph plus body text)". A 200-word summary paragraph therefore takes 200 words from Nature's body text, and nothing from JAMA's.
Thesis and dissertation abstracts
A thesis abstract is set by the university, and the published limits run from 150 to 600 words. North Dakota State is the strictest of the six in the table above, with separate figures by degree: "Abstracts for doctoral dissertations must use 350 words or less" and "Abstracts for master's papers or master's theses must use 150 words or less." Warwick's and Newcastle's research degree rules both allow 300 words, Newcastle's "in a form suitable for publication". MIT says "generally no more than 500 words single-spaced" and that the abstract "should be thought of as a brief descriptive summary, not a lengthy introduction to the thesis". NC State allows 600.
The rule can sit below the university, too. Cambridge's Department of Social Anthropology asks for a "summary/Abstract of about 500 words" with the PhD thesis, a figure set by the department rather than the university. Read the graduate school's handbook, then the department's.
Where 350 words for a dissertation comes from
The 350-word figure on many US university pages is tied to ProQuest, the database that publishes their dissertations. Antioch University's library guide records the change: "Abstracts no longer have length requirements in UMI/Proquest", but "the print version of the database will cut off at 350 words MAXIMUM." The 350 survives in many graduate school rules, NDSU's among them, which is why it is still the number to meet where a school states it.
Conference abstracts are often counted in characters
Many scientific meetings set a character limit, and they disagree on whether spaces count. The Society for Neuroscience's Neuroscience 2026 instructions say "the body of the abstract should be no more than 2,300 characters, including punctuation but not spaces", that "titles are limited to 1,200 characters, including spaces", and that "each image included reduces the character count by 500 characters". The Organization for Human Brain Mapping's 2026 guidelines split the body by section: 2,000 characters for the introduction and 4,000 each for the methods, results and conclusions, with a 100-character title, and there "character limits include spaces".
| Character limit | Spaces | Words that fit, roughly |
|---|---|---|
| 2,300 (SfN 2026 body) | Not counted | 375 |
| 2,000 (OHBM 2026 introduction) | Counted | 280 |
| 4,000 (OHBM 2026 methods, results or conclusions, each) | Counted | 560 |
The rates come from Nature's example summary paragraph, a dense piece of biology: 1,531 characters without spaces and 1,781 with them over 251 words, by our count, so about 6.1 characters a word without spaces and 7.1 with. Prose with shorter words fits more. Count the real text: the character counter gives both figures, and the word counter's limit can be set to characters with or without spaces.
How a submission system counts your words
A count that is fine in one tool can be over in another, and abstracts are full of the things tools disagree on. Nature's example paragraph shows how much: 251 words when microtubule-based and kinesin-5 count as one word each, 270 when every hyphen splits a word, a difference of 19 words in a paragraph of 250. Reference numbers glued to a word, such as proteins1,2, are one word to most counters and two or three to others.
Three habits avoid a rejected upload:
- Count with the strictest rule in sight. Paste the abstract into the word counter, type the limit and check the count under its two other rules; the guide to why word counts differ explains the hyphen split.
- Ask whether headings count. A structured abstract's headings, Objective, Design and the rest, are words to a counter. Some systems strip them before counting; the instructions rarely say. Count with and without them, and meet the limit both ways if you can.
- Count the version you submit. Abbreviations expanded at the request of IEEE, or reference numbers removed for PLOS ONE, change the count after the draft was checked.
Which limit wins
The receiving venue's limit beats every style guide. APA's own guide defers to "instructors or journals" with different requirements, and a thesis is governed by the university's rules even when the reference list follows APA. When a journal says 200 words and APA says 250, the abstract is 200. When no limit is given at all, APA's 250 words is a reasonable default for the social sciences and the journals in the first table show the usual band: 200 to 350.
Simple Online Counter is a free, browser-based set of counters, and its word counter counts an abstract's words and characters with a stated rule, shows the count under two other rules and keeps the text on the device. It checks length only; whether the abstract says enough is for the writer and the reviewers.
Frequently asked questions
How long should an abstract be?
Usually 150 to 350 words, but the only correct length is the one your journal, university or conference states. APA Style's 7th edition guide says to limit an abstract to 250 words. Among journals, IEEE allows up to 250 words, PLOS ONE 300 and JAMA 350 for reports of original data, while Nature asks for a summary paragraph of ideally no more than 200 words.
How many words is an APA abstract?
At most 250 words. APA's Abstract and Keywords Guide for the 7th edition says "Limit your abstract to 250 words", unless an instructor or journal asks otherwise. It sets no minimum, so the 150-to-250 range on many websites is not APA's 7th-edition wording. The abstract is one paragraph, not indented, on page 2, followed by three to five keywords.
How long is a thesis or dissertation abstract?
It depends on the university, and the rules differ more than most guides admit. North Dakota State allows 350 words for a doctoral dissertation and 150 for a master's thesis; Warwick and Newcastle allow 300; MIT says generally no more than 500; NC State allows 600. Your graduate school's own handbook decides, and a department may be stricter.
Does an APA student paper need an abstract?
Usually not. APA's 7th edition guide says abstracts and keywords "are not typically required for student papers" and tells students to ask their instructor or institution. When an instructor does ask for one, the same 250-word limit and format apply: a single double-spaced paragraph under the bold, centred label "Abstract" on the second page.
Is the abstract included in the word count?
It depends on the venue, so read the length rule closely. JAMA's 3,000-word limit for original research is "not including abstract", while Nature's typical 2,500 words for a six-page article covers the "summary paragraph plus body text". Thesis rules usually state what the main word limit excludes, such as the bibliography and appendices; check whether the abstract is on that list.
How many sentences are in an abstract?
Typically six to twelve. APA's guide lists six things an abstract covers, from the literature and research question to methods, results and implications, at "usually 1–2 sentences per topic". Nature's annotated example builds its summary paragraph from seven steps of one to three sentences each; the example runs to 12 sentences and 250 words.
How many characters is a conference abstract?
Each conference sets its own, so check the call for abstracts. Neuroscience 2026 (SfN) allowed 2,300 characters for the body, punctuation included but spaces not, and each image cost 500 of them. OHBM 2026 allowed 2,000 characters for the introduction and 4,000 each for methods, results and conclusions, spaces included. At about six characters a word, 2,300 is roughly 375 words.
Do hyphenated words count as one word in an abstract?
In most word processors and submission systems, yes, but not under every rule. Nature's own example summary paragraph is 251 words when a hyphenated term such as microtubule-based counts as one word, and 270 when every hyphen splits a word. Near a hard limit, count both ways or leave a margin of a few words.