Illinois CS Proficiency Exams

CS proficiency exams are given at the start of Fall and Spring semesters.

The exams are held around the start of classes each fall and spring, with any in-person exams being held after dorms open. Due to uncontrollable factors such as Covid-19 tending to change the university’s move-in arrangements, we will wait until about a month before the start of each term to pin down details (e.g. dates, are any exams offered online). At that point, we will update the information below so that it reflects the upcoming term.

Please watch this web page for the latest information.

If you have already mastered the material covered in certain Illinois Computer Science courses, you may receive credit and satisfy prerequisites by taking a proficiency exam. Here you will find details about how to prepare and sign up for Illinois CS proficiency exams.


Proficiency exams are similar in coverage and scope to a comprehensive final exam. They are intended to ensure that you are well-prepared for later courses in the same subject area. So we expect performance at the B- level or above. Specific passing criteria are at the discretion of each course instructor.

For the core programming sequence (CS 124, CS 128, CS 225) you must attempt the proficiency exams in order. Results are available immediately for the CS 124 and CS 128 exams, so you’ll know whether you can continue with the sequence. We will not grant proficiency credit for exams taken out of sequence.


Proficiency exams are offered at the beginning of each semester, and at other times at the discretion of the department.

Next Proficiency Exam Dates and Times

Spring 2023 proficiency exams will be held around the start of spring classes.

  • Friday January 13th, 1:30-4:40pm
  • Tuesday January 17th, 7-10pm

The exams will be given online with zoom proctoring. As we get closer to the exam dates, details will be added under the individual courses below.

Note that CS proficiency exams are no longer using the online CBTF. So there is nothing to sign up for on the CBTF website.

Note that most proficiency exams are three hours in length. You must arrive on time to take a proficiency exam.

General Restrictions

In certain cases you may not be eligible to take a proficiency exam. You are responsible for understanding these conditions. We will not attempt to determine whether you are eligible to take a proficiency exam before you take it. You will only find out later that you will not receive credit. So please review these restrictions carefully.

  1. You may not take a proficiency exam for a course that you have already received a grade for. This is true even if it was a failing grade.
  2. You may only take each proficiency exam once in a 12-month period. So, once you take a proficiency exam, you must wait a full year to retake the same exam. If you attempt the same exam before the year is up, your score will not be counted. This restriction applies regardless of how the proficiency exam is given.
  3. You may not receive proficiency credit for a course if you have taken a course in the same area. For example, you may not receive proficiency credit for CS 173 if you have already taken CS 374, since it is in the same area as CS 173. As another example, you may not receive proficiency credit for CS 124 if you have already taken CS 128, for the same reason. Instead of taking the proficiency exam, you may be required to substitute other later courses to fulfill your degree requirements.
  4. Graduate students generally may only take Illinois Computer Science proficiency exams when required to satisfy another degree program on our campus. Please have your advisor contact the CS academic office to obtain permission if needed.

Other course-specific restrictions may also apply. Please consult the information below specific to the proficiency exams you plan to take for more details.

Taking Your Proficiency Exam

To take a Zoom-proctored proficiency exam first sign up if your exam requires it (see specific course information below), then join the posted zoom session at one of the scheduled exam times. You must bring your University of Illinois ID to the proficiency exam, if you have one. If you show up late or without proper identification, you will not be able to complete the exam.

CS proficiency exams are using Zoom proctoring but not the online CBTF. However, you should still review the online CBTF instructions for how to set up your environment to enable Zoom proctoring. Review this overview and these instructions for phone positioning. You will need Zoom installed on your phone and configured to use your Illinois account.

Receiving Your Results

For the CS 124 and 128 exams are entirely autograded, so you will find out immediately whether you passed. Some of the other exams include some manually-graded questions, so it may take several days before your exam is graded. In that case, you will receive your proficiency exam results directly from the instructor supervising the exam.

Proficiency results are pass/no-pass only. You will not receive detailed feedback.

It may take several weeks for proficiency credit to appear on your official transcript. However, results are transmitted very quickly to the CS academic office so that we can issue appropriate overrides for updating your registration.

Information for Students with Disabilities

We will accommodate any disabilities that have been registered with the Division of Disability Resources and Educational Services (DRES). Please register with DRES to notify them of your disability and get an official letter documenting the accommodations you require. If you are new to the University of Illinois you should begin this process as soon as you are admitted.

If you qualify for testing-related accommodations, please review the information below for the specific proficiency exams that you plan on taking. Instructions should be provided for how to communicate your accommodation request. Please bring your letter of accommodation to your exam.

Please make these arrangements before your exam begins. In particular, for an extended-time exam, you will need to know whether you are expected to arrive early or stay late.

Questions or Concerns

If you have questions not covered here, or on the course-specific pages below, please send email to the proficiency coordinators at That is the best way to have your questions answered quickly. Please avoid contacting the course instructors directly.

Course-Specific Information

Please review the information below for any proficiency exams you plan to take.

CS 101: Introduction to Computing for Engineering and Science

  • Format: Computer-based
  • Length: 3 hours
  • Location: Zoom (instructions will be posted to participants)
  • Date and Time:
    • Friday January 13th, 1:30-4:40pm
    • Tuesday January 17th, 7-10pm
  • More Information: Available on the CS 101 website.

Sign-Up Process

Still needs updates for Spring 2023

Note that you must both schedule your exam using the form and also enroll in the “CS 101 Proficiency Exam” course on RELATE.

  1. Complete the signup form
  2. Log on to RELATE using your email address. (We will not give credit to students that take the exam using a non-university email address.)
  3. Enroll in the “CS 101 Proficiency Exam” course.
  4. We will email you and coordinate the Zoom-proctored exam.
  5. When complete, you must notify your proctor and submit your exam before leaving the Zoom session.

CS 105: Introduction to Computing for Non-Technical Majors

Note that the following information was not provided by the instructor and so may be incorrect. Contact the CS 105 Admin ( for more updated information.

CS 124: Introduction to Computer Science I

  • Format: computer-based
  • Length: 3 hours
  • Location: Online, proctored via Zoom during scheduled time windows
  • Dates and Times:
    • Friday January 13th, 1:30-4:40pm
    • Tuesday January 17th, 7-10pm
  • Zoom Link: Use this link for all scheduled times. You must log in with your Illinois NetID and password.
  • More Information: is available on the CS 124 website.

To join the proficiency course on PrairieLearn, log in to PrairieLearn using your Illinois login. Then join the CS 124: Introduction to Computer Science I, Proficiency Exam course.

After you join the PrairieLearn course there is no registration process for the CS 124 proficiency exam. Simply join the Zoom call at the beginning of one of the listed times and you will be able to access the exam while you are on the proctoring call.

The CS 124 proficiency exam is given in Java. CS 128 assumes that incoming students are familiar with Java, and students that are not have struggled. If you are proficient in another programming language and strong enough to start in CS 128, you should not have trouble learning Java to pass the proficiency exam.

Registration Process

Please log into PrairieLearn and enroll in the “CS 124: Introduction to Computer Science I, Proficiency Exam” course.

CS 125: Introduction to Computer Science

Proficiency exams are no longer offered for CS 125. Please take the CS 124 proficiency exam instead.

CS 128: Introduction to Computer Science II

  • Format: computer-based
  • Length: 3 hours
  • Date, Time, and Location: See this page’s Next Proficiency Exam Dates and Times section. We will give our proficiency exam on PrairieLearn. You will be given access to the test on exam day through our Secure Exam Service.
  • Registration:
  • Important Notes:
    • You must watch our “Secure Exam Service – What To Expect on Exam Day” video before your scheduled exam period.
    • Following our directions, procedures, or otherwise communicated here, on the CS 128 proficiency website, or within our information videos, are part of the proficiency exam. Failure to follow directions, procedures, or otherwise can lead to failure of the proficiency test.
    • In our Secure Exam Service, your registration will stay Processing until the registration deadline. We will batch-process all registrations once the registration deadline passes. Be sure to check your exam ticket for important information about your exam.
    • To make CS 128 lessons available to everyone, we published our Fall 2022 lessons to Learn C++ Online (
  • Coding Environment:
    • You will be required to author your responses to our programming questions using an in-browser instance of Microsoft Visual Studio Code. You can access a practice workspace by visiting PrairieLearn and enrolling in “CS 128: Introduction to Computer Science II, Proficiency Exam Environment Practice”.
  • More Information: is available on the CS 128 proficiency website.

CS 173: Discrete Structures

  • Format: computer-based, either on Moodle or PrairieLearn.
  • Length: 3 hours
  • Date, Time, and Location:
    • Friday January 13th, 1:30-4:40pm
    • Tuesday January 17th, 7-10pm
  • Zoom Links:
    • Friday: (Meeting ID: 812 3774 5248, Password: 103208)
    • Tuesday: (Meeting ID: 827 5306 8379, Password: 323795)

Additional information

Use to join the ‘course’ called “CSPX 173: Proficiency Exam for CS 173” on PrairieLearn. The exam itself may not be visible until the start time. There is no sign-up form to fill out.

You must be on the appropriate zoom session (see links above) the entire time that you are taking the exam. If your zoom session dies during the exam, get back on as fast as possible and consult with the exam proctors.

Use the conflict exam if you miss the main exam date for any reason. Prior permission is not required. However, it is normally better to take the exam on the earlier date, so that you will get results earlier and have an easier time adjusting your course schedule if needed.

The student code does not allow you to take the CS 173 Proficiency Exam after taking CS 374 (or a more advanced theoretical CS course).

The website for the Spring 2021 offering of CS 173 has a current set of skills lists, lecture notes, and videos. Course websites for Spring 2019 and earlier have old hardcopy exams that you can use for practice. (We have since moved the exams online.)

The exam will include some free-response questions (e.g. proofs) which are manually graded, so it will take a few days for results to be available. You are not required to use LaTeX to format your math, but you will be given a LaTeX reference sheet in case you want it.

CS 225: Data Structures

  • Format: Theory-based and programming-based questions, as a PrairLearn exam.
  • Location: Online, proctored via Zoom during scheduled time windows
  • Dates and Times:
    • Friday January 13th, 1:30-4:40pm
    • Tuesday January 17th, 7-10pm

Zoom Links:

Test Preparation Process

Enroll here. you will need to log on to PrairieLearn with your netID and then enroll in a course named “CS 225: Data Structures and Algorithms, Spring 2023 Proficiency”. Enroll yourself. You will return to this course when it’s time to take the proficiency exam.