WJEC GCSE Computer Science: the two units, Python and 2027 dates

WJEC GCSE Computer Science: the qualification

This is the Made for Wales GCSE Computer Science, approved by Qualifications Wales (approval number C00/4967/3). It is untiered, so every student can reach every grade from A* to G. Unit 1 was first awarded in 2026 and Unit 2 in 2027, and the specification suggests Unit 2 is best taken in the final year so you can use what Unit 1 taught. Its cover says it is not available to centres in England, where Eduqas has a separate GCSE Computer Science.

WJEC GCSE Computer Science papers

Unit 1 carries 30% of the marks for knowledge (AO1), 15% for applying it (AO2) and 5% for analysing problems (AO3). Unit 2 is 25% AO2 and 25% AO3, with no pure recall. Overall the weighting is 30%, 40% and 30%. Dates are from WJEC's final summer 2027 timetable; see our WJEC GCSE timetable 2027.

What each unit covers

Unit 1: Understanding Computer Science

• Computer architecture: components such as the CPU, motherboard and PSU, the Von Neumann architecture and the fetch-decode-execute cycle, peripheral devices and storage.
• Data: data types, representation, storage and compression, and converting between denary, binary and hexadecimal, including binary addition.
• Systems: networks and infrastructure, cybersecurity and personal privacy, operating systems, automated systems and the systems development life cycle.
• Software and logic: algorithms, principles of programming, program construction and logical operations, with legal, social, ethical and environmental issues built into the topics.

Unit 2: Computer Programming

WJEC sets a pre-release brief with a scenario, new each year, on the WJEC Portal in the first year of the course. In the exam you work on screen through tasks based on that scenario using Python 3, in the Python IDLE editor named in the brief. You cannot take prompts or notes in, and are given a clean copy of the pre-release material. The unit is built around investigation, decomposition, abstraction, pattern recognition, design, algorithms, data modelling, implementation, user interfaces, testing and refinement.

Worked examples in WJEC style

Unit 1: binary, hexadecimal and image size

Convert the 8-bit binary number 11010110 to denary and to hexadecimal. Add the place values for each 1:

Split the byte into two nibbles, 1101 and 0110, which are D and 6, so the hexadecimal is D6. A screenshot with no compression, 640 pixels across and 480 down, uses 24 bits for every pixel. Its size is:

That is 0.92 MB using 1 MB = 1,000,000 bytes. Divide by 8 to turn bits into bytes, and state which size convention you used.

Unit 2: a short Python task

Typical Unit 2 tasks ask you to read, process and output data. This loop finds the average of a list of marks, tracing 14 + 9 + 17 + 12 = 52, then 52 ÷ 4:

marks = [14, 9, 17, 12]
total = 0
for m in marks:
    total = total + m
print("Average:", total / len(marks))

The program prints Average: 13.0. Division with / gives a decimal in Python 3, and using len(marks) means the program still works if the list changes.

WJEC GCSE Computer Science grades

Raw marks become a uniform mark out of 100 for each unit. The two uniform marks are added to give a total out of 200 and a grade from A* to G; below G is unclassified (U). These are WJEC's published equivalences:

A unit can be resat once. See GCSE grades in Wales for the Welsh grade scale.

Use the daily paper as a short timed mock for WJEC GCSE Computer Science

Uni-Sine publishes a new free daily paper on each track: GCSE Computer Science. It is a short timed mock: 8 questions worth 25 to 35 marks, marked instantly, with worked answers. It is not a full exam paper and it is not written by the exam board, so use it as a quick timed practice test alongside the board's own specimen and past papers.

• What it covers well: computer systems and the CPU, networks, binary and hexadecimal, images and sound, cyber security, Boolean logic, algorithms, data types and programming fundamentals, which line up with Unit 1.
• What it does not cover: Unit 2. The daily paper is not an on-screen programming task based on a pre-released brief, so practise Python on your own computer in IDLE, using the sample assessment materials from WJEC.

Use one daily paper a day for Unit 1 recall, and set aside separate time each week to write and test Python programs.

Exam answers

Uni-Sine does not publish official answers, past paper answers or mark schemes from the exam board. The answers and a worked mark scheme for each daily paper come with that day's paper once it is marked, so you can see where every mark was won or lost.

Common mistakes in WJEC GCSE Computer Science

• Revising only theory. Unit 2 is half the grade and is a practical programming exam.
• Not learning the brief. You cannot take notes into the exam, so know the scenario well.
• Mixing up binary and hexadecimal groups. Four bits make one hex digit.
• Skipping testing and refinement in programming tasks. They are marks.

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UK · GCSEWJEC GCSE Computer Science grade boundaries 2026WJEC's June 2026 GCSE Computer Science boundaries out of 400, with unit boundaries, a weighted worked grade and the change since 2025.