Many factors should generally be considered when answering the question of how long is a PhD dissertation. However, students should limit their writing between 80,000 and 100,000 words. On average, this document should have around 204 pages. But, the average length of a PhD thesis also depends on the university and the specific subject.
Essentially, a university can set the requirements of a dissertation, including the length. Nevertheless, most institutions opt for around 100,000 words. Research has shown that STEM dissertations have a medium length of 159 pages. Non-STEM dissertations, on the other hand, have a medium length of about 223 pages. Thus, there is a significant difference in length between STEM and non-STEM dissertations.