Your advisor calls it a thesis, the graduate school website calls it a dissertation and a friend at another university insists it is the other way around. All three can be right, because in the United States nobody outside your own institution decides what the document is called.
A thesis is a substantial piece of written research submitted as part of a degree, in which you define a question in your field and answer it independently using recognized research methods. In US usage the word normally refers to the master's piece, while the doctoral work is called a dissertation. By the end of this article you will know who actually sets your length requirement, and it is not a federal agency.
📌 The key points at a glance
- US convention: thesis for master's, dissertation for doctorates.
- MIT uses thesis at bachelor's, master's and doctoral level.
- No federal authority sets thesis length or scope.
- Federal rules define the credit hour, not the thesis.
- Most graduate schools require electronic deposit after approval.
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General definition of a thesis
A thesis is a substantial piece of written research submitted for an academic degree, in which the writer defines a question, sets out a method, presents evidence and defends a conclusion. What changes between degree levels is the degree of originality expected, not the basic format of the document.
Cornell University's Graduate School describes the requirement in exactly those terms, calling the completion and defense of the master's thesis or doctoral dissertation the final requirement in earning a graduate degree. The University of Washington uses the same pairing for its electronic submission rules. Penn State adds the caveat that matters: while theses are common among master's students and dissertations among doctoral students, this may not apply universally across all programs.
Master's thesis: choosing the question yourself
A master's thesis asks you to take a manageable question from your field and work through it independently. The point is sound handling of the methods your discipline uses rather than a breakthrough finding. Whether you review existing scholarship or gather your own data depends on the field and on your committee, and both routes are entirely normal.
Doctoral dissertation: contributing something new
A doctoral dissertation has to add to what the field knows. You are expected to know the current state of research, develop a question that has not yet been settled and defend your approach before a committee. That expectation of originality, rather than length, is the real difference from a master's thesis. If you are still shaping your question, our guide to research questions, theses and hypotheses covers the distinctions.
Thesis or dissertation: what US universities mean
The safest assumption in the United States is that your own graduate school's wording overrides the general convention. Institutions write their own degree requirements, and those requirements decide what your submission is called, how long it may be and when it has to be deposited.
MIT is the clearest counter-example to the tidy rule. Its libraries require departments to submit each master's and doctoral thesis, and they note that not all departments send bachelor's theses to the libraries. At MIT the word thesis covers every level, which makes any blanket claim about American terminology unreliable.
The undergraduate thesis is a departmental decision
Undergraduate theses in the United States are usually optional and governed by the department rather than the university. Tufts describes the Senior Honors Thesis in History as an optional, intensive original research and writing project that students may choose to undertake. At UW-Madison, the College of Letters and Science notes that writing a thesis is required for most honors in the major programs and points students to their departmental advisor. Two universities, two different answers, both correct on their own campus.
💡 Tip
Read your department's page before your graduate school's page. Graduate schools set the deposit and formatting rules, but the questions students actually ask, about length, committee size and whether a thesis is required at all, are answered one level further down.
How long is a thesis in the United States?
No national rule sets the length of a thesis or dissertation in the United States. The Department of Education states plainly that the country has no ministry of education or other centralized federal authority exercising control over the quality of postsecondary educational institutions. Length is a matter for the institution.
Accreditors do not fill that gap either. The Department notes that although accrediting agencies promulgate standards to ensure institutional quality, agencies have no legal control over educational institutions or programs. One point of terminology worth knowing: the Department stopped recognizing accrediting agencies as regional in 2020, so the phrase regional accreditor is outdated even though it is still widely used (as of August 2026).
| Question | Set nationally? | Who decides |
|---|---|---|
| Thesis length | no | graduate school or department |
| Whether a thesis is required | no | the program |
| Value of a credit hour | defined, not fixed | institution and accreditor |
| Deposit after approval | no | the graduate school |
As of August 2026, subject to change.
The one federal definition that touches your workload is the credit hour. Under 34 CFR 600.2 a credit hour is an amount of student work defined by the institution and approved by its accrediting agency, reasonably approximating one hour of classroom or direct faculty instruction plus at least two hours of out-of-class work each week for roughly fifteen weeks per semester hour. Even that definition hands the actual number back to the institution.
What happens to your thesis after you submit it
Most US graduate schools require your approved thesis to be deposited electronically, and many of them publish it openly. This step is easy to overlook, because it happens after the defense, when the work already feels finished.
The University of Washington Graduate School requires all theses and dissertations to be submitted electronically and states that the document must eventually be made available openly on the web, hosted both in the university repository ResearchWorks and in the ProQuest database. Cornell requires submission within 60 days of the final exam. MIT deposits through its own repository instead (as of August 2026).
Why the deposit rule matters before you write
Open deposit affects what you are able to include. If your project uses company data, patient records or interview transcripts, the agreements you sign at the start determine whether the finished document can be published in full or needs an embargo. Raising this with your committee before data collection is far easier than negotiating it after the defense, when the deposit deadline is already running.
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Bachelor's, master's and doctoral work compared
Bachelor's, master's and doctoral projects differ mainly in how much independence they demand, not in how many pages they run to. The undergraduate thesis shows that you can apply your field's methods, the master's thesis that you can choose them, and the doctoral dissertation that you can extend what the field knows.
Naming follows that ladder only loosely. Cornell and the University of Washington use thesis for the master's and dissertation for the doctorate, MIT uses thesis throughout, and plenty of programs sit somewhere in between. The table below describes the expectations, which are far more stable than the labels.
| Piece of work | Degree | What it has to show |
|---|---|---|
| Senior or honors thesis | bachelor's | confident use of the field's methods |
| Master's thesis | master's | choosing question and method yourself |
| Doctoral dissertation | PhD or professional doctorate | an original contribution to knowledge |
One claim you will find repeated on commercial websites is that a master's thesis involves no original research while a dissertation does. No graduate school states that, and plenty of master's programs expect original data collection. Treat it as marketing copy rather than a rule, and check what your own committee expects. Our guide to empirical and theoretical theses explains how to make that call.
Conclusion
Thesis and dissertation describe the same kind of work at different levels, and in the United States the naming convention is helpful rather than binding. Nothing about length, structure or format is set nationally, and even the federal credit hour definition hands the number back to your institution. The documents that decide what you must submit are your graduate school's requirements and your department's handbook.
In the United States the word on the cover is a local decision. So is almost everything else about your thesis.
Where to go next
- Want to know how to structure the whole thing? Bachelor's thesis: structure and guide
- Still looking for a topic? Finding a topic for your thesis
- Planning to collect your own data? Running a survey for your thesis
Do you need your own data for your thesis?
With empirio.ai, an online survey tool from Germany, you can build a survey for your thesis and analyze the responses straight away. How to plan the survey for your thesis