References for PhD Positions in Europe

References for PhD Positions in Europe

Five of the six European PhD calls we checked ask for two or three referees, but the rule that matters is when the letters gate your application. At CRG Barcelona you cannot submit until both letters are in. At EMBL you submit first and referees have two more days. At CiM-IMPRS in Münster, one or no referee is "absolutely OK".

Counting referees is the easy part. The planning problem is the gate. When the letters gate submission, your referees' calendar becomes your deadline. When they are optional, the programme may contact your referee instead, so the referee needs to be ready for that. If you are the referee, your reference letter can get a free Quick Review before you upload it.

Every programme page quoted below was checked on 31 October 2026. Several of the calls have closed, and we say so in each row. A new call can change the rules, so recheck the call you apply to.

This page covers structured PhD programmes and doctoral positions with a published call. If you are approaching a German professor directly, our guide to recommendation letters for German universities and the DAAD covers that route. The cover letter for an advertised position has its own guide: PhD position cover letter sample.

How strictly references gate your application

The six rows sort into three models:

1. Letters gate submission. CRG says referees "must upload their reference letters before you can submit your application."
2. Letters gate consideration. EMBL says: "You can submit your application irrespective of whether your referees have completed the online reference form." But the letters still have a deadline, and IMPRS-IDI drops files without two.
3. Letters help but do not gate. CiM-IMPRS accepts one or none. Lund's humanities instructions list a CV, cover letter, study records, language proof, degree projects, publications and a project plan, and no references. A vacancy announcement can still add requirements, so read the advert too.

Our view: plan your referee timeline around the gate, not the count. For a CRG-type call, ask referees at least four weeks before the deadline and treat their upload as part of your own deadline. For an EMBL-type call, fill in the references part early and submit soon after: EMBL says referees "can access the online form after you have submitted", and the 2027 Winter round gave them only until 14 October. The countercase: for a CiM-type call, do not delay your application to chase a missing third person. Send it with the referees you have, and say who can be contacted.

Who European programmes want as referees

The three calls that name a preferred referee all put a research supervisor first.

• CRG: "Ideally, one should be your current or most recent supervisor, and at least one must be able to comment on your academic record and previous research experience." It adds: "Referees must not be affiliated with the CRG."
• IMPRS-IS: "we are particularly eager to hear from your past and current research advisors."
• CiM-IMPRS: "If possible, one of them should be your MSc research project supervisor."
• EMBL: applications "are evaluated solely on the basis of qualification and scientific potential."

So the master's thesis supervisor is the first name on these lists. If yours is not available, our page on a PhD reference without your thesis supervisor covers the substitutes.

Institutional email, stamps and the information email

EMBL. "We only accept references provided through institutional email accounts." If a referee has only a Hotmail or Gmail account, EMBL asks you to enter that address, tell the referee "NOT to complete the online form", and have them send "a reference letter on institutional headed paper, signed and stamped as a PDF document to graduate-office@embl.org", with your 8-digit application ID in the letter.

CRG. You cannot upload letters for your referees. Once you click "Send Request", referees get an email with instructions, and "you will not have access to their content."

CiM-IMPRS. The order is reversed. You name referees, wait for an information email, and forward it. Its warning: "Do not ask your referees to send us reference letters before you have received the information e-mail!"

IMPRS-IDI. Referees "will be contacted automatically once their details are saved, so please inform them in advance." It asks for each referee's email and phone number.

The email-domain problem is the same one US and UK portals have; our page on recommender email domains and letterhead compares those rules.

What a European PhD reference should say

The programmes above say whom they want. None of the pages we checked publishes the questions on its reference form. What they do say points one way: research. CRG wants someone who can "assess your potential as a PhD student", and EMBL evaluates "scientific potential". So the letter's job is to show what the candidate did in research when nobody told them what to do next.

European readers also read praise differently from US readers. Our guide to European vs American recommendation letters covers that calibration. In short: name the group you are comparing with, and state the grade in your own scale.

Constructed example: the research paragraph

Constructed example, written by us, not a real reference letter. Context (invented): a master's thesis supervisor writing for a structural biology PhD call.

Weak: Arjun was an excellent and hardworking student who always completed his work on time and showed great interest in research.

Revised: Arjun Mehta did his 30-week master's thesis in my group. In week 12 his protein stopped crystallising under the conditions we had used for two years. He did not wait for me. He set up a 96-condition screen, found that a buffer batch had changed, and documented the fix for the lab. Of the 14 master's students I have supervised since 2019, he is one of two I would hire as a doctoral researcher.

The revision gives an incident, the candidate's own decision, and a comparison group with a size. Those are the three things a reader in another country can use.

Preparing a referee for a call

CiM-IMPRS says: "We may contact the referees directly, if we need more information." Our recommendation: if a programme may contact your referee, assume the referee will be asked about details they wrote months ago. Give them a one-page briefing.

Constructed example: a referee briefing note

Constructed example, written by us, not a real applicant's note. It is 104 words, not counting the list numbers.

1. Position: doctoral position in cryo-EM methods, Group of Dr. L. Novak, [Institute]. Advert attached. Deadline 15 November.
2. How you know me: master's thesis in your group, February to September 2026, weekly meetings.
3. What I did: the buffer screen in week 12; the data-processing script the lab still uses; the poster at the departmental day in June.
4. What the group will ask about: independent work, wet-lab and computing skills, and whether I can write in English.
5. Practical: they may email or phone you in December. My application ID is 40213377. My motivation letter is attached so your account and mine do not contradict each other.

The note gives facts and dates. It does not suggest wording for the referee's assessment.

Before you enter your referees

1. Find the reference line in the call. Note whether letters gate submission, consideration, or neither.
2. Put the earliest reference deadline in your calendar as your own deadline.
3. Confirm each referee's institutional address. If one has only free email, follow the programme's fallback, as EMBL's four steps show.
4. Check the order of steps. Some portals email referees at once; CiM-IMPRS waits for an information email.
5. Put your research supervisor first. Check exclusions, such as CRG's rule against CRG-affiliated referees.
6. Send each referee the briefing note and the advert.

Questions about PhD references in Europe

How many references do I need for a PhD in Europe?

It depends on the call. In the six we checked: two at CRG, IMPRS-IDI and CiM-IMPRS, at least two at EMBL, three names at IMPRS-IS, and none in Lund's humanities instructions.

Can I submit my PhD application before my referees upload?

At EMBL, yes. At CRG, no: the letters must be uploaded first.

Do German PhD programmes need recommendation letters?

Structured programmes can. Both Max Planck schools in our table ask for referees, and CiM-IMPRS in Münster requests two. For the individual route, where you approach a professor directly, see our German universities and DAAD letter guide. Max Planck schools close referee letters with the call itself; the IMPRS motivation letter guide lists each school's rule.

Get a free review of the letter

Get a free Quick Review of your recommendation letter against GradPilot's international academic recommendation rubric. It reads for how you know the candidate, incidents rather than adjectives, comparisons and grades a reader abroad can use, your own voice, and a clear endorsement for this programme. For a US programme on the same list, use the graduate recommendation letter rubric.

GradPilot's letter reviews aren't for a letter you drafted for a recommender to submit as their own.

More PhD reference guides:

• PhD recommendation letter sample from a supervisor: a full constructed letter with notes.
• What PhD committees look for in recommendation letters: how research readers use a letter.
• ETH and EPFL recommendation letters for master's: the Swiss master's rules.

Hub: PhD essays.

Sources

Retrieved 31 October 2026, except where noted.

• Centre for Genomic Regulation, PhD International Call 2026 FAQ (2026 call; deadline 30 November 2025): two referees, letters before submission, eligibility rule, no access to content, CRG exclusion.
• Max Planck Institute for Infection Biology, IMPRS-IDI how to apply (call closing 10 December 2025): two referees, automatic contact, "will not be considered".
• EMBL, International PhD Programme application (2027 Winter Recruitment): minimum two academic letters, deadlines, institutional email rule and fallback.
• IMPRS for Intelligent Systems, Application (deadline 15 November 2026): three referees, research advisors.
• CiM-IMPRS Graduate Program Münster, Application (2026 call): two referees requested, one or none accepted, information-email order.
• Lund University Board for Third-Cycle Studies, Instructions for applying for a doctoral student position (4 December 2023): list of required attachments.