The degrees that take the longest to complete are combined MD-PhD programs and certain surgical residency tracks, which can require 12 to 16 years of post-secondary education and training. Even standalone doctoral degrees in the humanities routinely take seven years or more. The answer depends on whether you count only classroom time or include the supervised training and licensing steps that many fields require before you can actually practice.
PhD Programs: 5 to 9 Years
A doctorate is the highest academic degree you can earn, and the time it takes varies dramatically by field. The National Science Foundation’s Survey of Earned Doctorates found a median completion time of 5.8 years across all disciplines for degrees completed in 2020. But that median masks a wide spread.
STEM doctoral students tend to finish faster because their coursework and exam preparation phases are shorter, typically two to three years before they move into full-time research. Humanities and arts PhDs are a different story. The median time to degree for humanities and arts graduates in 2020 was 6.8 years, according to the American Academy of Arts and Sciences, and coursework alone consumed a median of four years before students began dissertation research. Some students in history, philosophy, or comparative literature spend eight or nine years completing their programs, especially when dissertation writing stalls or funding gaps force them to take on outside work.
Part-time enrollment stretches the timeline further. The core requirements are identical to a full-time program, but spreading coursework over more semesters and squeezing research into evenings and weekends can push completion past a decade. Factors like slow-moving research, extensive dissertation revisions, and life disruptions affect both full-time and part-time students, but part-time students have less margin to absorb delays.
Medical Degrees Plus Residency: 11 to 16 Years
Becoming a practicing physician in the United States requires four years of undergraduate education, four years of medical school, and then a residency that lasts three to seven years depending on your specialty. That puts the minimum at about 11 years after high school, and surgical specialties push it much higher.
Residency length varies by field. General surgery requires five years of postgraduate training. Orthopedic surgery and urology each take five years. Plastic surgery takes six. Neurosurgery, the longest residency, requires seven years. After residency, many physicians pursue fellowship training in a subspecialty, which adds one to three more years. A neurosurgeon who completes a fellowship in pediatric neurosurgery or spine surgery could spend 14 to 16 years in post-secondary education and training before practicing independently.
MD-PhD Programs: About 8 Years of Graduate Work
The Medical Scientist Training Program, commonly called the MD-PhD, combines a full medical degree with a research doctorate. These programs train physician-scientists who split their careers between clinical medicine and laboratory research. Duke University’s program reports an average time to degree of eight years: two years of medical school coursework, four to five years earning the PhD, and a final year of clinical rotations.
That eight-year figure covers only the combined graduate program itself. Add four years of undergraduate study before enrollment and a minimum three-year residency afterward (required to practice medicine), and the total investment from freshman year of college to independent practice reaches 15 years at a minimum. Surgical subspecialties after an MD-PhD can push the total past 18 years.
Architecture Licensing: 8 to 13 Years Total
Architecture is one of the longer paths outside of medicine. Most states require a degree from an NAAB-accredited program, which means either a five-year Bachelor of Architecture or a two-year Master of Architecture on top of a four-year undergraduate degree. After graduating, aspiring architects must complete the Architectural Experience Program, a structured period of supervised professional work that typically takes two to three years. They also need to pass the Architect Registration Examination, a six-division licensing exam that candidates often spread across a year or more.
From starting college to holding a license, the total timeline runs roughly 8 to 10 years. That is shorter than the medical track but substantially longer than most professional degrees like law (seven years total) or an MBA (six years total).
What Makes Some Degrees Take So Long
Three factors drive the longest timelines. First, the sheer volume of knowledge required. Neurosurgeons need to master general surgical principles before specializing, which is why their residency is seven years rather than three. Second, original research. A PhD is not just coursework; it requires producing new knowledge through a dissertation, and that process is inherently unpredictable. Third, sequential requirements. MD-PhD students cannot do everything simultaneously. Medical school, doctoral research, clinical rotations, and residency must happen in a specific order, and each phase has a minimum duration set by accrediting bodies or licensing boards.
Funding also plays a role. Humanities PhD students are less likely than STEM students to receive full research assistantships, which can force them into part-time status or teaching loads that slow their own research. Students who lose funding mid-program sometimes take leaves of absence that add years to their timeline.
Putting the Numbers Side by Side
- Humanities PhD: 6 to 9 years of graduate study (median 6.8 years), plus 4 years of undergraduate work
- STEM PhD: 4 to 7 years of graduate study (median around 5.8 years), plus 4 years of undergraduate work
- MD with surgical residency: 4 years of medical school plus 5 to 7 years of residency, plus 4 years of undergraduate work
- MD-PhD with residency: 8 years of combined graduate training plus 3 to 7 years of residency, plus 4 years of undergraduate work
- Architecture (through licensure): 5 to 6 years of degree work plus 2 to 3 years of supervised experience, plus the licensing exam
By total years from starting college to being fully credentialed, the MD-PhD followed by a surgical fellowship sits at the top, potentially exceeding 18 years. A standalone neurosurgery track comes in close behind at around 15 years. Humanities PhDs, while shorter in absolute terms, hold the record for the longest purely academic degrees, with some students spending nearly a decade in their doctoral program alone.