Summary
- A PhD (Doctor of Philosophy) is the highest academic degree you can achieve. It is awarded to candidates who complete original, independent research in a specific field of study.
- Full-time PhD programmes typically last three to four years in the UK and Europe, or five to seven years in the US. Part-time programmes typically last six to seven years.
- PhD study differs from undergraduate and taught postgraduate degrees because it is almost entirely research-based. You will work closely with a supervisor to produce a substantial thesis that contributes new knowledge to your field.
- A PhD can lead to an academic career in teaching and research, a role in industry research and development, or a wide range of other professions where advanced analytical and problem-solving skills are valued.
Introduction
More students are pursuing doctoral study than ever before. According to the Higher Education Statistics Agency (HESA), UK universities awarded over 26,000 doctoral degrees in 2023/24 (a figure that has grown steadily over the past decade). Globally, the trend is the same: PhD programmes in the US, Europe, Australia and beyond are seeing record numbers of applications.
But what is a PhD, exactly? What does the process involve, how long does it take, and is it worth the commitment?
Whether you are finishing an undergraduate degree, completing a Masters or considering a career change, this guide answers the question ‘what is a PhD?’ in full. We explain how doctoral programmes work across different countries, what the experience is actually like, and how to decide whether a PhD is the right step for you.
What does PhD stand for?
PhD stands for Doctor of Philosophy. The term comes from the Latin Philosophiae Doctor, where ‘philosophy’ refers to the original Greek meaning of the word: ‘love of wisdom’. You do not need to study philosophy to earn a PhD, the title applies across all academic disciplines, from engineering and biology to history and education.
You may also see the abbreviation written as Ph.D. (common in the US) or encounter the term DPhil, which is used by the University of Oxford and a handful of other institutions. All three refer to the same qualification. For a detailed comparison, see our guide to DPhil vs PhD.
What is a PhD degree?
A PhD is a doctoral research degree and the highest level of academic qualification you can achieve. Universities award PhDs to candidates who carry out original and significant research, write a substantial thesis and successfully defend their findings in an oral examination.
Unlike undergraduate and taught Masters programmes, a PhD is almost entirely research-based. Rather than attending lectures and sitting exams, you spend your time investigating a specific research question under the guidance of an academic supervisor. Some UK programmes, particularly those run through Centres for Doctoral Training (CDTs), include a year of taught modules at the start to build research skills, but the majority of your time is spent on independent research.
In most English-speaking countries, anyone who completes a PhD earns the title ‘Doctor’ (abbreviated to Dr). Some graduates working outside academia choose to use post-nominal letters instead (for example, Jane Smith PhD), though it is unusual to use both at the same time.
PhD vs doctorate: what is the difference?
All PhDs are doctorates, but not all doctorates are PhDs.
A PhD is the most common type of doctoral degree. It focuses on advancing theoretical knowledge through original research. A professional doctorate, on the other hand, applies existing knowledge to solve practical problems in a specific profession.
| PhD | Professional doctorate | |
|---|---|---|
| Focus | Original theoretical research | Applied, practice-based research |
| Examples | PhD in Chemistry, PhD in History | DBA, EdD, EngD, PsyD |
| Typical student | Aspiring academics and researchers | Working professionals |
| Outcome | Thesis based on original findings | Thesis or portfolio linked to professional practice |
| Duration | 3- years (UK), 5-7 years (US) | 3-6 years (often part-time) |
Both qualifications carry the title ‘Doctor’ and are recognised as terminal degrees. The right choice depends on whether you want to advance knowledge in your field or apply knowledge to your profession. For more detail, see our guides to DBA vs PhD and PsyD vs PhD.
What are the entry requirements for a PhD?
Entry requirements vary by country and institution, but most universities expect at least:
- A strong undergraduate degree (typically a 2:1 or above in the UK, or the equivalent internationally)
- A relevant Masters degree in many cases, particularly in the arts, humanities and social sciences. However, it’s still possible to start a PhD without a Masters, especially in STEM subjects, where strong lab experience or publications can demonstrate your readiness for postgraduate research at doctoral level.
In the US, most PhD programmes admit students directly after an undergraduate degree and include the Masters-level training within the first two years. In much of Europe, a Masters is typically expected before you begin. For a detailed side-by-side comparison, see our guide to Masters vs PhD.
Self-funded programmes can sometimes be more flexible with their entry requirements, particularly where candidates bring relevant professional experience.
Beyond grades, strong PhD applications usually include a well-written research proposal, academic references and evidence of your ability to work independently. For a full breakdown, see our guide to PhD entry requirements and the PhD application process.
How long does a PhD take?
The duration of a PhD depends on your country, subject and mode of study:
| Country / Region | Full-time duration | Structure |
|---|---|---|
| UK and Ireland | 3-4 years | Research-only from the start |
| United States and Canada | 5-7 years | 1-2 years coursework, then research |
| Germany, Netherlands, Scandinavia | 3-4 years | Often structured as a salaried position |
| France | 3 years typical | Funded through doctoral contracts |
| Australia and New Zealand | 3-4 years | Requires prior honours year or Masters |
Part-time PhDs in the UK typically take six to seven years. Most universities also allow an extension to the writing-up period of up to four years, at their discretion.
In STEM subjects, timelines can be affected by experimental work. A lab-based project may take longer if experiments need repeating or equipment is shared. In the humanities, the timeline often depends on access to archives or fieldwork sites.
Although many UK programmes start in September or October, PhD study is generally more flexible than taught courses and can begin at other points in the year.
For a more detailed breakdown, see our guide on how long a PhD takes. If you are considering fitting a doctorate around other commitments, our guide to part-time PhDs covers what to expect.
How much does a PhD cost?
PhD costs and funding options vary significantly by country. In some countries, doctoral students pay fees. In others, they receive a salary.
United Kingdom
- Home students: approximately £4,500-£6,500 per year (the UKRI benchmark rate is £5,006 for 2025/26, rising to £5,238 for 2026/27)
- International students: approximately £16,000-£25,000 per year
Most UK PhD students secure funding through studentships, which cover fees and provide a living stipend. The UKRI minimum doctoral stipend is £20,780 per year for 2025/26, rising to £21,805 for 2026/27. Students without a studentship can apply for doctoral loans from Student Finance England.
Europe
Many European countries offer PhD positions as paid employment rather than a student programme:
- Germany and Austria: PhD candidates are typically employed as research staff and receive a salary. There are usually no tuition fees at public universities. See our guide to PhD study in Germany.
- Scandinavia (Sweden, Denmark, Norway, Finland): PhD candidates are university employees with full benefits, pension contributions and a competitive salary. See our guide to PhD study in Sweden.
- Netherlands: Similar to Scandinavia, PhD candidates are employed for four years.
- France: Most PhD students receive a doctoral contract (contrat doctoral) providing a monthly salary. See our guide to applying for a PhD in France.
EU-wide funding is also available through the Marie Curie Fellowship programme, and German students can access DAAD research grants.
United States
Most STEM PhD students in the US receive full funding through teaching or research assistantships, which cover tuition and provide a stipend. Funding in the humanities and social sciences is less consistent and often requires a combination of assistantships, fellowships and loans.
Australia
The Australian Government’s Research Training Program (RTP) covers fees for domestic students. International students may apply for scholarships, though competition is strong. See our guide to PhD study in Australia.
For a full cost breakdown, see our comprehensive guide on how much a PhD costs.
What does a PhD involve?
A PhD programme typically moves through four key stages. The specifics vary depending on your subject, country and university, but the overall structure is broadly similar.
Stage 1: literature review and planning (year one)
Your first year centres on getting to grips with your field. You will attend regular meetings with your supervisor and carry out a thorough search of previously published work to produce a literature review. This sets the context for your project by establishing what is already known, where the gaps are, and how your research will contribute something new.
In STEM subjects, this stage often includes designing your experimental methodology, learning specialist techniques and securing ethics approval for any research involving human participants. In the arts and humanities, you may be developing your theoretical framework, identifying archives or planning fieldwork.
Towards the end of year one, many UK universities require an MPhil upgrade (sometimes called confirmation or transfer). You submit a progress report and defend it in a short oral assessment. This confirms you are on track and that your project is of PhD standard.
In the US, the first one to two years look different. PhD students complete coursework and pass qualifying or comprehensive exams before moving into full-time research.
Stage 2: research (year two)
With your research questions defined, the second year is where the core work happens. How this looks depends entirely on your discipline:
- In a chemistry or biology lab, you might be running experiments, collecting data and troubleshooting methods.
- In computer science or engineering, you might be building models, writing code or testing prototypes.
- In psychology or social sciences, you might be conducting interviews, running surveys or analysing datasets.
- In history or literature, you might be working through archival material, visiting special collections or analysing primary sources.
Throughout this stage, you will meet your supervisor regularly to discuss your progress, review results and adjust your approach as needed. Working with a view to publishing your findings is valuable. Many students submit their first journal paper during this period.
Stage 3: writing your thesis (years two to three)
Writing your doctoral thesis or dissertation typically takes between three months and a year. A thesis is a substantial document, usually between 80,000 and 100,000 words in the UK, that presents your research from start to finish.
In STEM subjects, theses tend to be shorter and may follow a ‘thesis by papers’ format, where each chapter is based on a published or submitted journal article. Some European countries, including the Netherlands and Scandinavia, use this cumulative format as standard.
Your thesis needs to demonstrate that you have:
- Identified a meaningful research question
- Used appropriate methods to investigate it
- Produced original findings that contribute to your field
- Analysed and discussed those findings in the context of existing knowledge
Stage 4: the viva voce (year three to four)
The final hurdle is the viva voce (usually shortened to ‘viva’). This is an oral examination in which you defend your thesis. How this works varies by country:
- UK and Australia: You are examined by two examiners (one internal, one external) in a private meeting that typically lasts two to three hours.
- US and Canada: You present and defend your thesis before a committee of four to five academics.
- Netherlands and Scandinavia: The defence is often a formal, public ceremony.
After the viva, you will typically receive one of three outcomes:
- Pass – you are awarded the PhD degree, sometimes subject to minor corrections. This is the most common outcome.
- MPhil – if your work does not meet the standard for a PhD, you may be offered an MPhil degree instead. This is uncommon.
- Fail – no award is given. PhD failure rates are extremely low.
For more detail on preparing for your oral examination, see our guide to the viva voce.
What is PhD life actually like?
A PhD is more than writing a thesis. Your day-to-day experience will depend on your discipline, your university and your supervisor, but there are some common themes.
Working with your supervisor. Your supervisor is your mentor throughout the PhD. They will help steer your research, offer feedback on your writing and provide career advice. The relationship is collaborative rather than instructional; they are there to guide, not to teach or do the work for you. Supervision styles vary: in STEM, supervisors often lead larger research groups, while in arts and humanities, the relationship tends to be more one-to-one. See our guide to working with your PhD supervisor.
Beyond the thesis. Most PhD students take on activities outside their core research. You might present at conferences, teach undergraduate classes, collaborate on publications with colleagues, or attend training workshops to build research skills. These activities develop your professional profile and are particularly important if you are considering an academic career.
Community and collaboration. PhD life can feel isolating at times, but most departments have a research community of fellow PhD students, postdocs and academics. In STEM, you may share a lab with a team; in the humanities, you might attend reading groups or seminar series. Many universities also run social and support networks specifically for doctoral researchers.
To hear what PhD life is actually like from those going through it, explore our series of PhD student interviews. For practical advice on getting started, see our tips for new PhD students.
What are the benefits of a PhD?
Career opportunities
A PhD opens doors to careers that require advanced research expertise. The most common paths include:
- Academic careers: lecturing, research fellowships and ultimately professorships. A PhD is the standard entry requirement for academic positions in virtually every discipline. See our guide to life after a PhD and postdoctoral positions.
- Research and development (R&D): PhD graduates are in demand across the pharmaceutical, biotech, technology and engineering sectors. R&D roles often offer competitive salaries and the chance to apply your research skills to real-world problems.
- Broader career options: A common misconception is that a PhD only leads to an academic career. In reality, HESA data shows that only around 23% of UK PhD graduates move into educational roles. The rest work in research, consultancy, data science, finance, policy, science communication and many other fields.
Transferable skills
Completing a PhD equips you with skills that are valued well beyond academia:
- Analytical thinking – breaking down complex problems and evaluating evidence
- Communication – presenting research in written and oral forms, from journal papers to conference talks
- Project management – planning and delivering a multi-year research project independently
- Data analysis – working with large datasets, statistical methods and specialist software (particularly in STEM)
For more detail, see our guide to transferable PhD skills.
Personal achievement
There is also the personal satisfaction of contributing original knowledge to your field, becoming a recognised expert in your area and earning the title of Doctor.
Is a PhD right for you?
Understanding what is a PhD is one thing; deciding whether to pursue one is another. A PhD is a significant commitment of time, energy and, in some cases, money. It is worth being honest with yourself about whether it is the right step.
Reasons to consider a PhD:
- You have a genuine passion for a subject and want to explore it in depth
- Your career goals require a doctorate (for example, academic positions, senior R&D roles or clinical research in STEM)
- You want to develop high-level analytical, research and problem-solving skills
- You enjoy working independently and managing your own projects
Reasons to think carefully:
- A PhD takes three to seven years and the financial return is not always immediate
- If your career goal does not specifically require a doctorate, relevant work experience may be more valuable
- Doctoral study can be isolating, and many students experience periods of self-doubt or low motivation
- Funding is not guaranteed, particularly in the humanities and social sciences
None of these are reasons not to pursue a PhD. They’re simply things to weigh up honestly. For a deeper look at the decision, see our guide on whether a PhD is worth it.
Types of PhD
Not all PhDs follow the same format. Depending on your circumstances, you may come across:
- Traditional PhD: The standard format – you carry out an independent research project and produce a thesis over three to four years.
- Integrated PhD: Combines a Masters year with three years of doctoral research. Common in UK STEM programmes through Centres for Doctoral Training (CDTs) and Doctoral Training Partnerships (DTPs). See our guide to integrated Masters with PhD.
- PhD by publication: Instead of a single thesis, you submit a collection of published journal articles with a connecting narrative. See our guide to PhD by publication.
- Industry-funded PhD: Your research is co-funded or sponsored by a company or organisation, often with time split between university and industry. Examples include CASE studentships in the UK and CIFRE contracts in France.
- Part-time PhD: You study alongside work or other commitments, typically over six to seven years.
- Distance learning PhD: Some universities offer PhDs with limited on-campus requirements, though you will still need to attend key milestones like the viva in person.
How do I find a PhD?
Finding the right PhD programme can feel daunting, but there are several good places to start:
- DiscoverPhDs: Browse our searchable database of PhD opportunities to find positions filtered by subject, location and funding status.
- University websites: Check the postgraduate research pages of universities you are interested in. Many list available projects alongside supervisor profiles.
- Your current department: If you are still at university, speak to lecturers and existing PhD supervisors. They often know about upcoming projects before they are advertised.
- Open days: Attend postgraduate open days to meet current PhD students and supervisors face to face.
- International portals: For EU positions, Euraxess lists doctoral vacancies across Europe. Country-specific portals also exist for many destinations.
For a step-by-step guide, see our advice on how to find your PhD.
Frequently asked questions
What does PhD stand for?
PhD stands for Doctor of Philosophy (from the Latin Philosophiae Doctor). Despite the name, a PhD can be earned in any academic subject, not just philosophy.
Is a PhD higher than a Masters?
Yes. A PhD is the highest academic degree you can achieve. A Masters is a postgraduate qualification, but a PhD goes further by requiring you to produce original research that contributes new knowledge to your field.
Does a PhD make you a Doctor?
Yes. Completing a PhD entitles you to use the title ‘Doctor’ (Dr). This is an academic title, different from a medical doctor (who holds an MD in the US or a medical degree in the UK). For a detailed comparison, see our guide to PhD vs MD.
How many years is a PhD?
A full-time PhD typically takes three to four years in the UK and Europe, or five to seven years in the US. Part-time study takes longer, usually six to seven years.
Can you get a PhD without a Masters?
Yes, though this varies by country and subject. In the UK, many STEM programmes accept students with a strong undergraduate degree. In the US, most PhD programmes include the Masters-level training within the programme.
Is a PhD the same as a doctorate?
A PhD is a type of doctorate. Specifically, the most common research-focused doctorate. Other doctorates include professional qualifications like the DBA, EdD and EngD, which focus on applying knowledge to professional practice rather than producing original theoretical research.
What is the difference between a DPhil and a PhD?
There is no difference. DPhil (Doctor of Philosophy) is simply the term used by the University of Oxford and a small number of other institutions. A DPhil and a PhD are the same qualification. See our DPhil vs PhD guide for more detail.
How is a PsyD different from a PhD?
A PsyD (Doctor of Psychology) focuses on clinical practice, while a PhD in psychology focuses on research. PsyD programmes follow a practitioner-scholar model; PhD programmes follow a scientist-practitioner model. For a full comparison, see our PsyD vs PhD guide.
Are PhDs funded?
Many are, particularly in STEM subjects. In the UK, funded studentships cover fees and provide a stipend. In much of Europe, PhD students are employed and receive a salary. In the US, funding through assistantships is common in STEM but less guaranteed in the humanities.
Conclusion
Now you know what a PhD is and what it involves. A PhD is the highest academic qualification you can earn. It requires sustained commitment (typically three to seven years depending on where and how you study) but rewards you with deep expertise, valuable transferable skills and access to careers in academia, research, industry and beyond.
Whether you are drawn to running experiments in a chemistry lab, analysing datasets in computer science, or exploring archives in the humanities, a PhD gives you the opportunity to make an original contribution to human knowledge.
Ready to take the next step? Browse PhD opportunities on DiscoverPhDs to find a programme that matches your interests, or explore our comprehensive advice library for guidance on every stage of the doctoral journey.
