OCR GCSE Computer Science (J277): papers, marks and grade boundaries

OCR GCSE Computer Science at a glance

OCR’s GCSE (9-1) in Computer Science is J277. It is a linear qualification, so both papers are sat at the end of the course, and it is the same for every student: there is no Foundation and Higher tier. Students also take on practical programming tasks during the course, which OCR asks schools to record in a Practical Programming Statement. There is no separate marked coursework: the skills are tested in Paper 2.

That is 160 marks in all. The assessment objective weightings are 30% AO1 (knowledge), 40% AO2 (application) and 30% AO3 (analysing, designing, programming and refining).

What each paper covers

Paper 1: Computer systems

Every question is compulsory. The paper has multiple choice, short response and extended response questions, including one 8 mark extended response question that tests a sustained line of reasoning. It covers six topics:

• 1.1 Systems architecture: the CPU, the fetch-decode-execute cycle, clock speed, cores and cache, embedded systems.
• 1.2 Memory and storage: RAM and ROM, secondary storage, units, binary and hexadecimal, character sets, images, sound and compression.
• 1.3 Computer networks, connections and protocols: LAN and WAN, topologies, wired and wireless, the internet and protocols.
• 1.4 Network security: threats and how to prevent them.
• 1.5 Systems software: operating systems and utility software.
• 1.6 Ethical, legal, cultural and environmental impacts of digital technology.

Paper 2: Computational thinking, algorithms and programming

Section A (50 marks) tests concepts and applying them to problems, often through algorithms. Section B (30 marks) tests practical programming: designing, writing, testing and refining programs. It covers 2.1 Algorithms (including searching, sorting and flowcharts), 2.2 Programming fundamentals, 2.3 Producing robust programs, 2.4 Boolean logic and 2.5 Programming languages and integrated development environments.

In Section B, questions that ask you to write or refine an algorithm can be answered in the OCR Exam Reference Language or in the high-level programming language you are familiar with, so use the language your teacher taught and write it neatly.

Calculator and what to learn

Calculators are not permitted in either paper, so practise converting between binary, hexadecimal and denary by hand. Most of the marks are for facts, definitions and methods that you must know, and code you must be able to write and trace.

Worked examples in OCR style

Number systems: denary, binary and hexadecimal

Convert the denary number 203 to 8-bit binary and then to hexadecimal. Use the place values 128, 64, 32, 16, 8, 4, 2, 1:

Split the byte into two nibbles, 1100 and 1011. Those are 12 and 11, which are C and B in hexadecimal, so 203 = CB in hexadecimal. Check the other way: 10110110 in binary is 128 + 32 + 16 + 4 + 2 = 182, which is B6 in hexadecimal. Practise more in our Number Systems course:

Programming: totals and averages

Write an algorithm that reads five test marks and outputs their mean. Reference-language style code:

total = 0
for i = 0 to 4
    mark = int(input("Enter a mark"))
    total = total + mark
next i
print(total / 5)

Trace it with the marks 12, 15, 9, 20 and 14. The total builds up as 12, 27, 36, 56 and 70, and the output is 70 ÷ 5 = 14. Mark schemes give a mark each for initialising the total, a loop that repeats five times, reading and converting the input, adding to the total, and outputting the mean. Declare the total before the loop, not inside it.

Boolean logic and a sorting pass

For Q = (A AND B) OR NOT C, take A = 1, B = 0 and C = 0. A AND B is 0, NOT C is 1, so Q = 0 OR 1 = 1. Build the full truth table with 8 rows by counting in binary from 000 to 111.

One pass of a bubble sort on 5, 2, 8, 1 compares neighbours and swaps when they are in the wrong order: 5 and 2 swap, 5 and 8 stay, 8 and 1 swap, giving 2, 5, 1, 8. The largest value has moved to the end. Repeat until a pass makes no swaps.

Grades and June 2026 grade boundaries

The J277 papers are added into a total out of 160, which is then compared with the grade boundaries. OCR does not give a grade for each paper. The table below is from OCR’s document published on 25 September 2026 for the June 2026 series. Boundaries change each year, so use them as a guide.

Worked through: 100 marks out of 160 is 62.5%. That is above the grade 5 boundary of 92 and below the grade 6 boundary of 108, so it is a grade 5. A grade 4 needed 77 marks (48%) and a grade 7 needed 124 marks (77.5%).

Using the daily paper as a short timed mock

Uni-Sine publishes a free daily paper on the Computer Science Higher track, with a new one every day. It is a short timed paper of 8 questions worth 25 to 35 marks, marked instantly with worked answers. It is not an OCR paper and it is not a full 80 mark paper, so use it for quick practice without a calculator and alongside OCR’s own past papers.

• It covers well: the CPU and computer systems, networks and protocols, binary and hexadecimal, programming fundamentals, representing images and sound, cyber security, algorithms and flowcharts, data types and structures, Boolean logic, and searching and sorting.
• It does not cover: the 8 mark extended response style of Paper 1, or writing long programs for Section B. Do those from OCR past papers.

For more on mocks, see our GCSE mocks guide and the GCSE Computer Science guide, plus the GCSE Computer Science mock paper page.

Taking the WJEC Eduqas course instead? Read our Eduqas GCSE Computer Science guide, which has its own papers and boundaries.

Exam answers

Uni-Sine does not publish official answers or mark schemes for OCR GCSE Computer Science papers. The answers and a worked mark scheme for each question come with today’s paper once you have submitted it and it has been marked, so you can see where every mark was won or lost.

Common mistakes in OCR GCSE Computer Science

• Mixing up the CPU parts. The ALU does calculations and logic, the control unit manages the cycle, and registers hold the data in use.
• Writing "it is faster" for everything. Say what is faster and why, such as a larger cache reducing trips to RAM.
• Off-by-one errors in loops. A loop from 0 to 4 runs five times.
• Printing when the question says return, or the other way round in a function.
• Short answers to the 8 mark question. Give both sides, link each to the scenario and finish with a conclusion.

Read next

UK · GCSEOCR GCSE Computer Science grade boundaries 2026OCR GCSE Computer Science (J277) June 2026 boundaries for grades 9 to 1, with Paper 1 and Paper 2 figures and three years side by side.