Ucis, Candidate Numbers and Centre Numbers Explained
Three different numbers appear on an exam entry, and only one of them follows you for life. Confusing them is the most common reason a practical endorsement or coursework carry-forward silently fails.
At a glance
- UCI: 13 characters, follows you
- Candidate number: 4 digits, one series
- Centre number: 5 digits, one centre
- Carry-forward matches on the UCI
9 min read10 questions answered
A Unique Candidate Identifier (UCI) is a thirteen-character code that stays with you across schools, colleges and awarding bodies and is used to make entries and collect your results over time; a candidate number is a four-digit number that identifies you within one centre for one series; and a centre number is the five-digit code that identifies the centre itself.
The Three Numbers Side by Side
| Identifier | Length | Scope | Changes? |
|---|---|---|---|
| Unique Candidate Identifier (UCI) | 13 characters | Across all centres, all awarding bodies, all series | No. It follows you. |
| Candidate number | 4 digits | One centre, one series | Yes. Usually different every series. |
| Centre number | 5 digits | Identifies the centre | No, but it changes when you change centre. |
All three appear on a statement of entry and on a statement of results. Only the first one matters for carry-forward.
How a UCI Is Built
AQA publishes the structure. The first five characters are the centre number of the centre that allocated it. The sixth character is a zero for AQA exams. The seventh and eighth are the last two digits of the academic year in which the UCI was allocated. Characters nine to twelve are the candidate number held at that time. The thirteenth is a check character generated automatically.
Read that structure again and notice what it means: your UCI permanently records the centre and year in which you were first entered. When you move, the UCI does not update. A UCI beginning with a school's centre number is still your UCI at a different college five years later, and that is correct rather than an error.
This is why a UCI can look wrong to someone who does not know how it is built, and why candidates sometimes get issued a second one by a centre that assumes the first is stale. That assumption is the problem, not the number.
Why the UCI Decides Whether a Carry-Forward Works
A carry-forward request asks the awarding body to find a result you already hold and attach it to a new entry, a science practical endorsement Pass, or an NEA or coursework mark.
The awarding body finds that result by matching on the UCI. There is no other reliable key: your name may have changed, your date of birth is not unique, and your candidate number certainly is not.
So if a resit entry is made under a newly generated UCI, the carry-forward has nothing to match against. The entry will process, the exams will happen, and the endorsement will simply be absent from the result. That failure is invisible until results day unless somebody checks the statement of entry.
This is not a rare edge case. It is the single most common way a science resitter loses an endorsement they were entitled to keep. See does the practical endorsement carry forward.
Step by step
Finding and Using Your UCI
Look at Your Statement of Results
The UCI is printed on statements of entry and statements of results issued by the awarding body. If you have kept any exam paperwork from a previous series, it is there.
Ask the Centre That Entered You
Schools and colleges hold candidate records including UCIs. This is a routine request and does not require a reason. Ask the exams officer rather than a teacher.
Ask the Awarding Body
If the centre has closed or cannot help, the awarding body holds the record against your UCI. They will ask for identity evidence before releasing it.
Give It to the New Centre in Writing
Send the UCI, the awarding body, the specification code and the series of your previous award in a single written message, and ask for written confirmation that the same UCI has been used on the new entry.
Check the Statement of Entry
When the statement of entry arrives before the exams, check the UCI on it against the one you supplied, and check that any carry-forward is shown. This is the last easy moment to fix an error.
Questions
Questions About Exam Identifiers
A thirteen-character code that identifies you as a candidate across time and across different exam boards, schools and colleges. Awarding bodies use it to make entries and collect results for you consistently.
Every candidate entered for a GCSE, AS or A-Level has one, whether or not they have ever been told what it is.
Thirteen characters. On AQA's published breakdown: characters one to five are the centre number that allocated it, character six is a zero for AQA exams, characters seven and eight are the last two digits of the academic year of allocation, characters nine to twelve are the candidate number held at that time, and character thirteen is an automatically generated check character.
It is not a memorable number and nobody expects you to know it by heart. Write it down somewhere you will find it again.
A candidate number is four digits and identifies you within one centre for one series. It must be unique within that centre and series, and it is not reused between GCSE and A-Level candidates in the same series.
A UCI is thirteen characters and identifies you permanently, across every centre and awarding body you ever deal with. The candidate number is a seat number; the UCI is a passport.
A five-digit code identifying an approved exam centre. It appears on statements of entry, statements of results and on the front of the answer booklets you complete in the exam room.
It is also the first five characters of any UCI that centre allocated. The centre entering you will confirm its number to you as part of the entry process.
On a statement of entry or statement of results from any previous series. Failing that, from the exams officer at the school or college that entered you, or from the awarding body with identity evidence.
Start with the paperwork. It is faster than any of the alternatives.
No, and you should not. The whole purpose of the UCI is that it survives a change of centre, which is why it is used to collect results across different schools, colleges and exam boards.
Your UCI will still begin with the centre number of the centre that first allocated it. That is expected and is not a sign that it is out of date.
Because a carry-forward request for a practical endorsement or an NEA mark is matched on the UCI. If the new entry carries a different UCI, the awarding body cannot find the result you are asking it to carry.
The entry will still process. You simply will not get the endorsement, and you will not find out until results day.
Your record is split: previous results sit under one identifier and the new entry under the other. Carry-forward will fail and results can be reported incompletely.
Awarding bodies can merge duplicates, but the request has to go through the centre and it takes time. Raise it the moment you notice, not after results.
Yes, every candidate needs one, private or internal. If you have been entered for a public exam before, you already have one and it should be reused. If you have never been entered for anything, the centre entering you will allocate one.
A first-time candidate has nothing to carry forward, so allocation is straightforward. A returning candidate should always supply the existing UCI.
Almost certainly not. Candidate numbers are allocated per centre per series and must be unique within that series, so a different centre or a different year normally means a different number.
This is nothing to worry about. Nothing important is matched on the candidate number.
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Oliver Moy
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