How long is a PhD? – PhD length overview

A PhD is the highest degree a person can achieve in a specific field. To earn a PhD, the student must show academic and research mastery in their subject. Doctorate programs are very rigorous and often take several years to complete. In the US, an average PhD student will take a little over 8 years to complete their program. The length of a PhD program depends on many factors:

  • Subject: What is the field of study of the PhD?
  • Time Commitment: Full-time or part-time?
  • Previous experience: Has the student completed related coursework in the past?
  • Location: Where is the student completing the PhD?
  • Other: demographics, program focus (research vs. professional), etc.


Fields of study are a crucial factor when making projections on the length of a PhD program. According to the 2018 Doctorate Recipients from US Universities Report [1], on average, the duration of a PhD in the US is 8.6 years. Doctorate programs in Physical Sciences or Statistics were the shortest with an average completion time of 6.9 years. The second quickest was Engineering, with an average length of 7.3 years. On the other hand, PhD degrees in Education took an average of 14.7 years to complete.

If you would like more information about time to degree for other majors, you can find a link to the 2018 Doctorate Recipients from US Universities Report on the resource section below.

Time Commitment

When pursuing a PhD in the US, students are usually completing a combined Masters plus PhD program. First, they complete related coursework during the first 2-3 years. Then, they continue the program by diving into the research world.

There are many ways to complete a PhD. Some students drop their current job and become a full-time student. Others decide to commit to the program on a part-time basis, in some cases, due to family or work obligations. Some students even consider completing an online degree. Online programs allow them to work at their own pace, avoid moving from their current location, and avoid long commutes.

There is no definite rule between how long a student takes to complete a PhD and their time commitment: full-time or part-time. In general, a student taking half of the course load will take many years (4 years instead of 2) just to complete the academics of their program. Also, considering doctorate programs take almost a decade to finish, life can get on the way. Some graduate students will have to switch their time commitment back and forth and adapt it to their personal situation.

A crucial factor that influences the individual’s time commitment to a doctorate program is funding. Unfortunately, some PhD students never earn enough funding to cover their tuition and living expenses. Therefore, they must apply for student loans or work on the side.

Previous Experience

In the US, the vast majority of PhD programs accept applicants that just finished a Bachelor’s degree. It is not required to complete a Master’s to get accepted into a PhD program. However, it will make a difference in the overall length of the program.

Incoming students entering the program with a Bachelor’s degree must complete the full doctorate program without exception. The program entails 2-3 years of coursework and several years of research to complete a dissertation. These incoming students must complete all the coursework and pass qualifying exams. Once the student has passed the qualifying exams, then their primary focus is research.

Other incoming students have previously completed a Master’s degree in the same field of study. In this case, the university can convalidate part of their coursework and streamline the coursework requirements. However, this is not always guaranteed and depends on the institution. A factor to keep in mind is that universities are more likely to convalidate courses if the degree was awarded recently. Due to their previously acquired knowledge, students with a Master’s degree can be ready to pass the qualifying examinations earlier. Then, they shorten the classroom portion of their program and continue to the research portion.

If the incoming student has been awarded a Master’s degree in another field of study, then it will be difficult to convalidate courses. However, there are some exceptions with related fields such as marketing and business administration or physics and mathematics.


The statistics mentioned in this article are based in the US. But, there are prestigious doctorate programs all over the world. The location where a student pursues a doctorate can also influence the overall length of their program. For example, PhD programs in Europe tend to be shorter than in the US. Yet, they might require a Master’s degree for admissions.

PhD length, research portionThe overall PhD completion time statistics vary dramatically across institutions. As a result, many institutions publish their own statistics, including completion length to help prospective students set realistic expectations (here is an example from Duke University). No Ph.D. program has a set timeline, but some tend to be shorter. Some universities focus on additional counseling or supervision to help candidates complete their degrees promptly. Also, the culture within the university can influence the length of a program. Research advisors might be used to give students an excessive number of side projects and responsibilities. Other cultures are more balanced; they encourage students to complete their research efficiently.

Final Thoughts

Even though it takes most students almost a decade to complete a PhD, many are eager to pursue these programs. In 2018, 55,000 [1] PhD degrees were awarded in the US. And, the general trend shows an increase in incoming and graduating PhD students over the years.

Pursuing a PhD is an academic, mental, and personal challenge. Doing the appropriate research is the first step towards getting accepted and completing a doctorate. Students are more likely to complete their degree if they have reliable funding from the university, support from their family, and are content with where they live. If you are considering applying for a PhD program, we have several articles that can help you with your research. These two articles will help you get you started: “Finding the right PhD program” and “How to get into a PhD program?”. The first goal towards earning a PhD should be getting accepted into the right PhD program. One that matches your goals and meets your funding and completion time expectations.

Find the Right Ph.D. Program: Main Considerations (including funding)

How to get into a Ph.D. program? 7 crucial steps to success