How long should be a Doctoral Dissertation or Thesis?

How long should be a Doctoral Dissertation or Thesis?

A doctoral dissertation or thesis should be of 50,000 to 80,000 words and should not exceed 1,00,000 words having around 150 to 230 pages. 

“One size can’t fit to all.” 

A fat person can’t fit into a lean person’s trouser, isn’t he?

The same is true for the most important academic essay as well, the PhD thesis or dissertation or we can say a doctoral dissertation.

The present article illustrates how long should be a PhD dissertation! the number of words, number of chapters and pages. We will also discuss what should be your thesis length and how you can decide it. But before that let’s understand the concept of a doctoral dissertation or thesis. 

The doctoral dissertation or thesis is almost the same kind of thing! Some universities prefer to say it as “dissertation” while others say it “a thesis” but ideally, as per the USA PhD structure, the dissertation is considered as a short essay and often applied to denote a thesis to award the master degree.

Notwithstanding, we can use either term to indicate a PhD essay.  Either a thesis or dissertation, any of it can be used. So don’t confuse yourself. 

The PhD dissertation is an academic essay, structured, formal and concise and precisely written. The whole thesis must be divided into specific chapters each one includes specific information. 

For example, the introduction chapter includes general information only while the review chapter must include literature and reviews of all related topics. 

The content of the dissertation may vary from chapter to chapter that we will discuss later on. Sections of every PhD dissertation have a definite content and length as well, and therefore the whole thesis has a definite length. 

The criteria to write a PhD dissertation (what to write and how to write) vary among universities, some prefer longer essays while some shorter. Let’s not confuse things and let directly into the topic, 

Read more: 12 Proven Practical Tips for Academic Writing.

How long should be a doctoral dissertation or thesis? 

The ideal length of the doctoral dissertation is between 50,000 to 80,000 (actually), however, should not exceed 1,00,000 words.

Do you know? 

“A New Determination of Molecular Dimensions” is a thesis title of Albert Einstein which has only 17 pages.

The whole doctoral dissertation divides into sections like background (commonly an introduction), review, methods, results, discussion and conclusion. 

Besides, Acknowledgement, preface, abstract, index, list of images, list of tables and title page and other pages are there in the thesis but can’t be included in the core content of the doctoral dissertation. 

In accordance with the number of pages, a typical thesis has a minimum of 180 and a maximum of 300 pages with an average of 230 pages per dissertation and consider as the ideal length of the doctoral dissertation. 

However, here are some of the factors upon which the length of the thesis is decided. 

  1. The subject chosen
  2. The topic of the doctoral dissertation 
  3. University selected 

The length of the thesis varies among subjects as some need longer, in-depth explanation whilst some only contain equations or mathematical calculations. 

Usually, dissertations of humanities such as history, language and social science are long around 1,00,000 to 1,20,000 words. On the other side, the dissertation of STEM ( Science, Technology, Engineering and Mathematics) are shorter around 50,000 to 80,000 words. 

Here is the graph of the number of pages and length of the thesis in different subjects. 

Another factor is a topic chosen by the prospective student. The length of the doctoral dissertation also depends on a topic selected, independent of the subject. 

For example, some topics are shorter and “require to the point” explanation, topics of maths and physics are based on equations and calculations henceforth those theses ideally might be shorter than other topics. 

On the other side, a topic that includes not only scientific experiments but also physics or maths and social benefits are usually longer. The reason is that prospective students need to explain the science behind that and its importance for society as well. So it may be huge. 

Related article: 16 Proven Tips to Write a Thesis for PhD.

The style of writing, length and structure of dissertation may vary among universities. Universities have their own style and students have to write their thesis accordingly.

Do you know? 

David Rector’s thesis entitled, “An unstable Adams Spectral Sequence” is the shortest thesis in the world having only 9 pages (as per the MIT library of thesis). 

Note that the quality of the doctoral dissertation isn’t associated with the length of it. Consequently, a longer thesis isn’t mean quality work whilst a shorter thesis isn’t mean poor work! 

Plenty of research data are available on the length of the doctoral dissertation and the number of pages but interestingly, conclude nothing! 

This means, research conduct on 1000 student show that the thesis should have 1,00,000 pages doesn’t infer that you have to write a dissertation of exactly having the same length.

Dr Eva Lantsoght had conducted a poll on Twitter on “what was the word count of your dissertation?” 

34% of students voted that their thesis is 80,000 to 1,20,000 words long while 21% of students voted to have a dissertation length of fewer than 40,000 words. However, the study is irrelevant as students aren’t categorized based their subjects. (but it’s just a Twitter Poll!). 

As we said, the number of pages or words may deviate among universities, for example, ideally Cambridge university allow 80,000 words in a typical dissertation, however, in the same university the criteria for biology PhD thesis is 60,000 (as per their official website information).

Note that special permission is needed when students exceeds more than the limit decided.

Similarly, Oxford university and Harvard university advised dissertation length of 1,00,000 and 100 to 300 pages, respectively.

No such data or studies define how long exactly a doctoral dissertation should be because as we said, it’s not a major criterion in any university. If you write a thesis in either fewer or more words, the university will never reject it or fail you, based on that. 

Irrespective of the length of the dissertation, it must justify the research work done by the prospective candidate. If the examiner thinks that the thesis is too long, they advise you to make it shorter and vice versa, no issue in that. 

The only thing matter is that the work should be worth award-winning. However, some universities are strict against the length of the doctoral dissertation. Students need prior permission if their thesis excess the length decided by the university. For example, at Cambridge University, the length of a doctorate dissertation is fixed for different subjects. When exceeded, one has to take permission prior to submit the thesis. 

Do you know? 

Historian Joachim Schuhmacher had written the world’s longest thesis having 2,654 pages. 

Now let us discuss how the length of a doctorate dissertation is decided? 

The answer to this question gives you an idea of “how many words you have to write”. A single thesis page should have around 325 to 333 pages when using Times New Roman font and double spacing (as per the MLA and APA formate). 

When you write 100 pages it comprises 33, 300 words so when we write 250 pages, it comprises around 83,250 words. 

It means one should have to write around 60,000 to 70,000 words (220 to 230) pages for getting a doctoral degree. Again, keep in mind, not the length, the quality of research work and writing precision decides the fate of a student. 

Importantly, the ideal length of what we are discussing here only comprises content, we haven’t included other important pages such as a preface, acknowledgment, title page or other related pages. Those are single pages and must be labeled in italic, not in numbers. 


Refer university’s official circular or terms and conditions before applying as well as submitting a thesis. Do not trust blindly what others are doing.


What is the conclusion of the present topic? You may wonder I will advise you on how long a doctoral dissertation will be. Right! Well, in that case, I strongly recommended to contact the university and ask to the PhD department regarding requirements.

Keep in mind quality of research matter more rather than the quantity of writing. Still, you need to write a doctoral dissertation longer enough to evaluate.  

“Don’t consider yourself as Einstein or David Rector.”

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