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How Many Years Does It Take To Complete a PhD?

Written by Kristine Bagdassarian

The the length of a PhD depends on a range of factors, such as your funding arrangements, your country and institution of study, and the nature of your research topic. For example, if you’re doing a funded PhD you’re more likely to face completion deadlines than self-funded PhD students. So, in reality, how many years does a PhD usually last? A full-time PhD in the UK usually takes between three and four years, while a part-time project typically lasts between five and six years.

Increasingly, the type of programme you’re enrolled in can also affect the duration of your doctorate degree. Some projects or programmes now include additional training, teaching or projects that can extend your overall PhD registration period.

The flexible nature of the PhD degree compared to other academic qualifications means that some variation in the duration of study exists. This page explains some of the typical scenarios that can affect how many years a PhD degree lasts.

On this page

How long is a full-time PhD?

Full-time study is the most common approach to PhD research, particularly for funded projects. You’ll normally spend at least three years of full-time PhD study on your topic, beginning with research and data collection before moving on to ‘writing up’ your work.

As with other levels of study, your PhD will be your main focus and you’ll be expected to dedicate a lot of your time on it. Some students do work part-time alongside their studies, but a full-time PhD itself can often be the equivalent of a full-time job.

Why three to four years?

Compared to other qualifications, a PhD takes a considerable amount of time.

When you are just starting, three to four years may seem like a long time to work on a single project, but the volume of work required to obtain a doctorate is substantial and many students find that the time goes by faster than anticipated.

By the end of this period, you’ll be expected to have completed any training required by your funding body and / or institution, gained research skills and conducted original research and, finally, submitted and defended your thesis. Some universities and projects may also expect (or even require) you to present your work at conferences or publish some of it during your doctorate.

In addition to this, it’s advisable to have engaged in extra-curricular activities and projects to boost your professional and academic skillset. Between three and four years is plenty of time to do this, but it’s nowhere near as long as it might seem.

For more information on what you can expect during your project, take a look at our introduction to PhD study.

PhD registration period and writing-up period

The stated length of your PhD normally refers to the ‘registration period’ you set with your university at the start. This is the time period you intend to complete your PhD in and it will normally determine the ‘deadline’ for submitting your final thesis.

In the UK, the PhD registration period for full-time students is normally between three and three and a half years. In some departments and institutions, there is an understanding that students might enter a ‘writing-up’ period towards the end of their PhD. This is usually an extension to your registration, during which you don’t carry out any more research and just work on finalising your thesis and editing it for submission – writing it up, basically.

Can you complete a PhD in fewer than three years?

It’s technically possible to complete some PhDs in two years, if you have a very clear idea of the questions you want your project to answer and you’ve already done a lot of preparatory reading. This is very uncommon, however, and something that you should discuss with your supervisor. Some universities won’t let you submit a thesis before a certain point.

How many hours should I work while doing my PhD?

If you’re doing a full-time PhD, it’s wise to treat it like you would a full-time job, working the equivalent of 35 hours a week. However, you should be prepared to work longer hours during particularly busy stages of your doctorate, such as the writing up period and when you’re preparing for your viva.

Can you extend the length of a PhD?

Yes, it’s usually possible to extend the length of a PhD. You’ll need to apply to your university for an extended thesis submission date and have a valid reason for doing so (for example, a delay caused by something out of your control, COVID-19, a medical emergency or a bereavement). You should bear in mind that an extension isn’t guaranteed – particularly if it’s been caused by poor planning on your part. If your PhD has funding attached, there will usually be stricter deadlines than if you’re self-funding.

How long is an integrated PhD programme?

It’s quite common in STEM subjects to do an integrated PhD that includes a Masters qualification, usually taken after an undergraduate degree and referred to as a 1+3 PhD. These kinds of PhD typically take four years to complete.

How many years does it take to do a part-time PhD?

Part-time PhDs normally take about twice the time of full-time PhDs (around five to six years in the UK). You’ll do everything a full-time PhD student does across your doctorate, but your PhD work will be a less intensive part of your weekly routine.

This type of PhD is a good way to accommodate other employment and / or family commitments alongside your research.

In some cases, it may even be possible to start on a part-time PhD and switch to full-time study (or vice versa) if your situation changes.

How long is a distance learning PhD?

Distance learning is an option if you’re unable to be physically present at your university. Most distance learning PhDs are also studied part-time and take around five to six years.

This option is increasing in availability, but can be trickier to manage in some fields that require regular lab work or access to specialist facilities. As a long-distance PhD student, you can expect to communicate with your supervisor via email, Skype or other electronic means as well as potentially attend the institution of your study for a couple of weeks each year.

The length of PhD funding

However you study your PhD, your funding situation can play a big role in determining how long your registration lasts – and / or how long you can afford to research for. Most scholarships and studentships have set lengths (which won’t necessarily cover writing up).

In some cases, funding can also add extra elements to a PhD, and potentially increase its overall length. Alternatively, limitations set by your department or research group funding could urge you to finish your thesis in the three-year period without additional extensions, while self-funded PhDs could greatly depend on your own resources.

Structured PhDs

In the UK, many PhD programmes funded by the Research Councils are offered as ‘structured’ or ‘new route’ PhDs. These incorporate additional training projects, professional internships and other elements.

Such elements may take place alongside your research, or specific time may be set aside for them. In some cases, students are only matched up with a supervisor at the end of the first year. These sorts of programmes are often offered within Centres for Doctoral Training (CDTs) or Doctoral Training Centres (DTCs).

Self-funded PhDs

Self-funding (unsurprisingly) is not restricted by funder deadlines and can be more flexible – particularly if you need to extend for writing up. However, self-funded PhDs require careful planning for tuition and living costs alongside any ‘hidden’ expenses, such as equipment and travel to events / conferences.

Although self-funding can ease the stress surrounding a strict final deadline, it is important to keep in mind that resources for support can place pressure on completion of the project. In addition, universities also still tend to set a maximum registration period.

Registration period and funding period

Sometimes your registration period can also be tied to your PhD funding. Most studentships only last for a certain time (even if your doctorate ends up taking longer) and payments for a doctoral student loan will be based on the stated length of your project or programme.

PhD length in different countries

If you have your eyes on doing research abroad, there are a few things you need to be aware of in terms of study length. The three to four year PhD model is typical for the UK and most of Europe, with some countries in Asia also adopting a similar system (specific information on PhD studies in various countries can be found in our study abroad section).

Length of a full-time PhD
UK 3 to 4 years
USA 4 to 6 years
Canada 3 to 6 years
Australia 3 years
France 3 to 4 years
Germany 3 to 4 years
China 3 to 4 years
Japan 3 to 4 years

The US PhD model has a longer span of four to six years. There are several reasons for this. While in the UK, you tend to apply for a specific project, in the US, your application is aimed at a certain department and your actual proposal takes shape in the first couple of years of PhD study. The US model involves a two-phase programme, wherein the first phase is focused on coursework and training and the second phase (typically from the third year onward) is when the bulk of the research is done. At the end of the second year, a US student would be expected to have developed a research proposal to be defended in front of a research committee and to have passed a ‘qualifying exam’ in order to present their defence.

Find a PhD

The best way to find out how long a PhD is in your subject is to have a look around. Check our PhD database or, for more information on PhDs, explore the rest of our advice section!

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Last Updated: 09 May 2023