IB Diploma Computer Science SL and HL: the new course first examined in 2027

IB Computer Science assessment from 2027

Programming is needed for some Paper 2 questions, and those questions come in equivalent Java and Python versions, so you answer in the language you studied. The course also includes a collaborative sciences project. These details are from the IB's Computer Science subject brief for first assessment in 2027. The old course was last assessed in 2026.

IB Computer Science topics

The IB recommends 150 teaching hours at SL and 240 at HL, including 35 hours for the computational solution and 10 for the collaborative sciences project. HL goes much further in machine learning, OOP and abstract data types.

IB Computer Science exam dates 2027

The IB's May 2026 schedule says the May 2027 exams will run from Friday 23 April to Wednesday 19 May 2027, with no exams on 1 May, subject to confirmation. Your IB coordinator has the subject-by-subject timetable for your zone.

IB grades and points

Each subject is graded from 1 to 7. Six subjects at up to 7 points each, plus up to 3 points from theory of knowledge and the extended essay, make a maximum of 45. The IB says the diploma needs at least 24 points and that other conditions must also be met. Grade boundaries are set for each subject after every session, so a raw mark from one year doesn't map exactly onto the next. Our IB mocks guide explains how points add up and how predicted grades work.

Worked examples

Networks: transfer time

How long does a 50 MB file take to send over a 20 Mbit/s connection, ignoring overheads? 50 MB is 50 × 8 = 400 megabits, so the time is 400 ÷ 20 = 20 seconds. Real transfers take longer because of protocol overheads and congestion.

Databases: an SQL query

To list the names of students in Year 12 in alphabetical order from a table called Students:

SELECT Name
FROM Students
WHERE Year = 12
ORDER BY Name;

Programming: a linear search in Python

def find(items, target):
    for i in range(len(items)):
        if items[i] == target:
            return i
    return -1

The function returns the index of the first match, or −1 if the target isn't there. In the worst case it checks every item, so for n items it is O(n). A binary search on a sorted list needs only about log₂ n checks.

Count the halvings in a binary search in our Search Algorithms course, then press Mark to check your answer in the course:

Use the daily paper as a short timed mock

Uni-Sine publishes a free daily paper for IB Computer Science. Each is a short timed mock: 8 questions worth 25 to 35 marks, with a suggested 35 to 45 minutes, marked when you finish. It is not a full IB paper, and the questions are original, not past papers.

• What it covers well: databases and SQL, networking, data structures, object-oriented programming, recursion, searching, sorting and complexity, and processor architecture.
• What it does not cover: machine learning, the case study, and the computational solution. It also includes topics such as regular expressions and finite state machines, which you should check against the new IB syllabus.

For full papers under exam conditions, use IB past papers from your teacher, and read our IB mocks guide for how mocks feed your predicted grades.

Common mistakes in IB Computer Science

• Revising from old-course materials. The 2027 course has a new structure, including machine learning; check every resource is for first assessment 2027.
• Ignoring the case study. Paper 1 includes three questions on it, and HL spends 30 hours on it.
• Writing code that only nearly works. Trace your code with a small example before moving on.
• Confusing bits and bytes. Network speeds are usually in bits per second; file sizes in bytes.

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