How Long Should Each Dissertation Chapter Be?

No rule sets one page count for each chapter, and any number you find online belongs to someone else's program. Length depends on your field, your design, and your institution. The way to learn your range is to ask and to count.

Find your range in three steps

Read your program handbook. Some programs set a total page limit or a word range. Few set one for each chapter, but check.
Ask your chair. "How long are the chapters in the last few dissertations you supervised?" gets a more useful answer than a general question.
Count three approved dissertations from your own department. Open your university's repository, pick three recent ones in your area, and note the pages in each chapter. Those figures are the standard your committee has already accepted.

How the chapters compare

In most dissertations, the chapters keep a recognizable shape in relation to each other, though the numbers differ by field and design.

Chapter 1, introduction. Shorter than the middle chapters. It sets up the problem, purpose, questions and significance, and it does not review the literature in depth. See what Chapter 1 should include.
Chapter 2, literature review. Among the longest. Its length depends on how many bodies of literature your question draws on. See how many sources a review needs.
Chapter 3, methodology. Medium length, and it must be detailed enough for another researcher to repeat your steps. See Chapter 3.
Chapter 4, results. Length follows the data. A qualitative study with several themes and quotations usually runs longer than a short quantitative results chapter. See Chapter 4.
Chapter 5, discussion and conclusions. Shorter than the literature review, and long enough to interpret the findings against the literature and state limitations and recommendations. See Chapter 5.

If one chapter is very short compared with the others, the committee will ask whether something is missing from it. If one is much longer than the rest, ask whether part of it belongs elsewhere.

Reading a length comment

A comment such as "too long" or "too thin" is rarely about the page count alone. A long chapter usually has repetition, summary where analysis belongs, or material that belongs in an appendix. A thin chapter usually has claims without evidence or sections that were not developed. Find the cause before you add or cut.

Do not pad, and do not cut blindly

Adding words to reach a number weakens the document, and a committee reads the argument, not the count. Cut repetition, move tables and long instruments to appendices, and add only what supports a claim. Whatever the length, the chapters must use the same key terms and answer the same research questions.

Want a reader to check whether your chapters are balanced?

The Two Dissertation Moms offers a Dissertation Manuscript Review that reads the whole document as one argument and tells you which chapters need development or cutting.