Blog

Difference Between CAS and Offer Letter

Table of Content

1. Introduction

2. What an Offer Letter Means

3. What a CAS Means

4. Key Differences Between CAS and Offer Letter

5. Why Confusing CAS and Offer Letter Causes Problems

6. Which One You Need at Each Stage

1. Introduction

One of the most common mistakes Nigerian students make during the UK study process is confusing a CAS with an offer letter. Many students assume that once an offer letter is issued, they are ready to apply for a UK student visa. This misunderstanding has caused unnecessary delays, visa refusals, and missed intakes.

Although both documents come from a UK institution, they serve very different purposes and are issued at different stages of the admission process.

In this guide, we clearly explain the difference between CAS and offer letter, what each one means, when you receive them, and how Nigerian students should use them correctly to avoid problems.

2. What an Offer Letter Means

An offer letter is the first official document a UK school issues to confirm that you are eligible for admission into a course.

When you receive an offer letter, it means the institution has reviewed your application and is willing to admit you, subject to certain conditions. These conditions may include submitting final certificates, paying a tuition deposit, or meeting English language requirements.

Offer letters can be:

Conditional, meaning you still need to meet specific requirements
Unconditional, meaning all conditions have already been met

It is important to understand that an offer letter does not allow you to apply for a UK student visa. It is simply an admission confirmation.

Many Nigerian students stop at this stage and delay the next steps, not realizing that additional actions are required before visa application.

3. What a CAS Means

A CAS, which stands for Confirmation of Acceptance for Studies, is issued after you accept your offer and meet all required conditions.

The CAS is a unique reference number generated by the school and sent to you electronically. This number is entered directly into your UK student visa application and confirms that the institution is sponsoring your studies.

Unlike an offer letter, a CAS includes:

Your course start and end dates
Tuition fees and deposit paid
Sponsor licence details
Confirmation that you are eligible for visa sponsorship

If you are not fully clear on how a CAS works, this guide on the CAS letter meaning for Nigerian students explains it in detail and shows why it is central to the UK visa process. Without a CAS, you cannot submit a valid UK student visa application.

4. Key Differences Between CAS and Offer Letter

The main difference between a CAS and an offer letter lies in purpose and timing.

An offer letter confirms that you are eligible for admission, while a CAS confirms that you are officially accepted and sponsored for study.

Another major difference is usage. An offer letter can be issued to many students without restriction, but a CAS is tightly regulated by UKVI and can only be used once for a visa application.

Timing also matters. Offer letters are issued early in the application process, while CAS letters are issued later, usually after deposits are paid and documents are verified.

Understanding these differences helps students avoid rushing into visa applications prematurely.

5. Why Confusing CAS and Offer Letter Causes Problems

When students confuse an offer letter with a CAS, they often make serious mistakes.

Some attempt to apply for a visa using only an offer letter, which leads to automatic rejection. Others delay important steps, assuming the CAS will be issued automatically.

This confusion also affects timelines. Students who do not understand the CAS stage often apply late, which increases the risk of delays. This guide on how long it takes to get a CAS after offer explains realistic timelines Nigerian students should plan around.

In more serious cases, delays can lead to CAS withdrawal or missed intakes. This is why understanding the full process early is critical.

6. Which One You Need at Each Stage

At the application stage, you need academic documents and submit them to receive an offer letter.

At the acceptance stage, you accept the offer, meet conditions, and pay required deposits.

At the visa stage, you need a CAS. Without it, your visa application cannot proceed.

Students who understand this flow usually experience fewer delays and less stress. This step-by-step guide on how to apply to UK universities from Nigeria shows how offer letters and CAS fit into the full application journey.

For students who want clarity before moving from offer to CAS and visa application, AfriXGlobal Connect provides structured guidance through its UK Study Advisory, starting with an Initial Eligibility Check to ensure everything is done correctly. You can learn more here.