Confirmation of Acceptance for Studies: What Your CAS Number Means for Your UK Student Visa

Your UK Student visa application cannot even begin without a CAS number. It is the single document that ties your visa to your specific course at a specific university. Without it, there is nothing for UKVI to assess. Get the details wrong — wrong course level, incorrect tuition balance, wrong start date — and the application falls apart.

Here is what the Confirmation of Acceptance for Studies actually is, when universities issue it, what it contains, and what you need to check before you apply.

What a CAS Number Is

The Confirmation of Acceptance for Studies (CAS) is not a physical document. It is a unique electronic reference number — typically a string of letters and numbers — generated by your sponsoring university in the UKVI Sponsor Management System.

When your university creates a CAS record for you, it lodges with the Home Office a structured data record containing:

• Your full legal name and date of birth
• The course title and its RQF level (e.g., Level 6 for bachelor's, Level 7 for master's)
• The course start and end dates
• The full tuition fee and how much you have already paid
• The academic qualifications you used to obtain your offer
• Any conditions on the offer

The CAS reference number is what you enter into your online Student visa application form. UKVI uses it to pull the full record from the system and assess your application against the rules in Appendix Student.

When Universities Issue CAS Numbers

Universities issue CAS numbers according to their own internal schedules, but the Home Office places strict outer limits.

Under paragraph ST 1.2(d) of Appendix Student, your CAS must have been assigned no more than 6 months before the date you submit your visa application. A CAS older than 6 months is invalid and cannot be used.

Universities typically begin assigning CAS numbers for the September intake in late May or June. For a January intake, CAS assignment usually starts in October. Most universities wait until they have confirmed all outstanding conditions on your offer — including any deposit payment — before issuing the CAS.

Do not expect your university to issue a CAS the moment you accept your offer. There is always a processing delay. If you are in a high-scrutiny market (Nigeria, Pakistan, Sri Lanka), universities may conduct additional due diligence before CAS assignment, which can add weeks.

How Long After CAS Can You Apply?

Once you have your CAS number, you can apply for your Student visa within the following windows under Appendix Student:

• From outside the UK: You can submit no earlier than 6 months before the course start date stated in your CAS — and you must apply before the course begins.
• From inside the UK (extensions or switching): You can apply up to 3 months before the new course start date, provided the new course starts no more than 28 days after your current permission expires.

Most students from outside the UK aim to submit their application 3 months before the course starts. This gives enough processing time (standard is 3 weeks after biometrics) and leaves a buffer for any delays.

What to Check in Your CAS Before Applying

Errors in your CAS record are a significant and preventable cause of visa refusal or processing delays. Before you enter your CAS number into the application form, verify the following with your university:

Course level: The RQF level must match your actual award. A master's degree is RQF Level 7. A bachelor's is RQF Level 6. If this is wrong, your application may be refused or you may be granted the wrong visa conditions.

Tuition fee balance: The CAS records the remaining tuition fee you owe — this is what UKVI uses to calculate part of your financial requirement. If your university has recorded the wrong amount (e.g., not accounting for a deposit you have paid), you may be required to show more in maintenance funds than you actually need to.

Course start date: This must match the actual term start date. The visa processing window is calculated from this date. An incorrect start date could mean your visa is refused (applied too early) or you arrive without valid leave.

Name and date of birth: Your CAS must match your passport exactly. A middle name missing from the CAS when it appears in your passport, or a date format error, can trigger identity verification delays.

If you find an error, contact your university's international student office immediately. They need to correct the CAS record in the Sponsor Management System before you submit. Do not apply with a CAS containing known errors.

What Happens If Your CAS Expires?

If 6 months pass between when your CAS was assigned and when you submit your application, the CAS is no longer valid. You need to go back to your university and request a new CAS assignment. Universities can reissue a CAS for the same course, but this restarts the clock on document validity — including your financial evidence, which must be dated within 31 days of the application submission date.

If your course start date has also changed in the meantime, the new CAS will reflect the new dates. This often happens with January-intake students who apply late.

CAS and the Graduate Route

The CAS number you used for your Student visa becomes relevant again when you apply for the Graduate visa. Under Appendix Graduate, you are required to provide your previous CAS reference number as part of the Graduate visa application. It is how UKVI confirms which institution sponsored your Student visa and that the completed course is eligible for the Graduate Route.

Keep a record of your original CAS number throughout your studies.

What Low-Risk Country Applicants Should Know

If you are applying from a "low-risk" country under paragraph ST 22.1 of Appendix Student — which includes most EU/EEA nationals, Australians, Canadians, Americans, and others — you are not required to submit your academic qualifications or financial documents at the point of application. The CAS still functions identically; it is simply that UKVI opts not to request those supporting documents upfront.

This does not mean you can avoid preparing them. UKVI caseworkers can request financial and academic evidence at any point during adjudication. If you cannot produce compliant documents when asked, your application will be refused.

The full student visa application process — including the financial evidence rules, biometrics, ATAS requirements, and the complete timeline from CAS to Graduate visa — is covered in the UK Student Visa + Graduate Route Guide.

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