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GCSE · Last updated November 2026

GCSE Computer Science (9-1) Exam: free practice test

GCSE Computer Science covers how computers work and how to solve problems with algorithms and code. With OCR (J277), the most common board, you sit two 1 hour 30 minute papers of 80 marks each: Paper 1 Computer systems and Paper 2 Computational thinking, algorithms and programming. Exams are taken in the May/June series at the end of the course, and there is no coursework.

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About the GCSE Computer Science exam

GCSE Computer Science covers how computers work and how to solve problems with algorithms and code. With OCR (J277), the most common board, you sit two 1 hour 30 minute papers of 80 marks each: Paper 1 Computer systems and Paper 2 Computational thinking, algorithms and programming. Exams are taken in the May/June series at the end of the course, and there is no coursework.

What's on the exam

GCSE Computer Science
Systems Architecture, Memory and Storage
8 key facts
Data Representation
8 key facts
Networks and Network Security
8 key facts
Systems Software and Ethical, Legal and Environmental Issues
8 key facts
Algorithms
8 key facts
Programming Fundamentals and Robust Programs
8 key facts
Boolean Logic and Programming Languages
8 key facts

Each branch is a topic in the official outline. Members see every key fact on the full mind map. Read the free study guide →

How to pass the GCSE Computer Science exam

  • 80 marks in 90 minutes is just over a minute per mark. Short recall questions should take less than that so you have time for the longer algorithm questions in Paper 2 Section B.
  • Both papers are non-calculator. Practise binary, hexadecimal and file-size calculations by hand, and show your working because method marks are available.
  • Use a trace table for every 'what is output' question: one column per variable and a new row each time a value changes.
  • Read command words: 'state' needs a fact, 'describe' needs a point with detail, and 'explain' needs a reason (because...). For 'compare', say which is better and why.
  • When writing code, use clear variable names, indentation and correct structure. Examiners accept OCR Exam Reference Language or a high-level language such as Python, but the logic must be precise.

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Create a free account after the test: your score by topic, a mistakes bank, the complete study notes for the first topic, flashcards and the GCSE Maths Formula Sheet.

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What's in the premium GCSE Computer Science prep

Premium GCSE Computer Science prep is studied one topic at a time. Each step starts with that topic's key notes and flashcard deck, then its own question sets of 25, so you master one topic before you move to the next. When every topic is strong, the 6 full mock exams show you're ready.

3,000practice questions, every answer explained
6full-length mock exams, 277 questions each, timed
800flashcards with spaced repetition, sorted by topic
60comprehensive key notes across 7 topics

Your step-by-step study path

  1. 1
    Systems Architecture, Memory and Storage9 key notes, 115 flashcards, then 450 practice questions in 18 sets of 25
    Notes free with an account
  2. 2
    Data Representation9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
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  3. 3
    Networks and Network Security9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
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  4. 4
    Systems Software and Ethical, Legal and Environmental Issues9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  5. 5
    Algorithms8 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
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  6. 6
    Programming Fundamentals and Robust Programs8 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  7. 7
    Boolean Logic and Programming Languages8 key notes, 110 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  8. Final step: 6 full mock exams277 questions each, timed like exam day. Hit your target on them before your first paper.
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Free with an account

Read the complete GCSE Computer Science study notes for “Systems Architecture, Memory and Storage”

Our first full set of comprehensive notes, about 14 minutes of reading: The purpose of the CPU · Von Neumann architecture and its registers · The fetch-execute cycle step by step · What affects CPU performance · Embedded systems · Primary storage: RAM, ROM and virtual memory · Secondary storage and choosing a device, a worked exam example, the traps examiners use and a one-minute recap. Create a free account to read it and see how premium notes work before you decide.

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Study tools included

3,000 practice questions

3,000 exam-style questions per exam, organised topic by topic in sets of 25. Every answer explained, with the rule it comes from.

6 full mock exams

6 full-length timed mock exams per exam, with real question counts and time limits, so test day feels like practice day.

Exam Readiness Score

One 0 to 100 number that tells you when you're ready for exam day. Reach 80 and you're covered by our Pass Guarantee.

800 flashcards + spaced repetition

800 flashcards per exam, in a deck for each topic, that come back right before you'd forget them. Five minutes a day keeps every number fresh.

60 comprehensive key notes

60 key notes per exam, split across its topics and each explained in full: the concepts, worked exam examples, the traps examiners use and a quick recap. Your first set is free with an account.

Mind maps

See the whole exam on one screen: every topic and the facts under it.

Sample questions with answers

These are the questions in the free test above, with answers. Try the test first. You'll learn more by getting some wrong.

1. In the von Neumann architecture, which register holds the address of the next instruction to be fetched?
Answer: Program counter (PC). The program counter holds the address of the next instruction. That address is copied to the MAR, the instruction arrives in the MDR, and the PC is incremented.
2. Why does a computer slow down when it relies heavily on virtual memory?
Answer: Virtual memory is part of secondary storage, which is much slower to access than RAM. When RAM is full, the operating system moves data that is not currently needed to virtual memory on secondary storage. Transferring data back and forth to the much slower drive makes the computer slower.
3. What is the binary number 10110110 in denary?
Answer: 182. Place values 128, 64, 32, 16, 8, 4, 2, 1. The 1s are at 128 + 32 + 16 + 4 + 2 = 182.
4. What is the denary number 213 in hexadecimal?
Answer: D5. 213 ÷ 16 = 13 remainder 5. 13 is D in hex, so 213 = D5. Check: 13 × 16 + 5 = 208 + 5 = 213. 5D is the digits in the wrong order.
5. An image is 100 pixels wide and 80 pixels high with a colour depth of 4 bits. What is its file size, ignoring metadata?
Answer: 4000 bytes. File size = colour depth × width × height = 4 × 100 × 80 = 32 000 bits. Divide by 8 to get bytes: 32 000 ÷ 8 = 4000 bytes (4 KB). 32 000 is the size in bits, not bytes.
6. Which protocol is used to access email on a mail server so that messages stay on the server and can be read from several devices?
Answer: IMAP. IMAP keeps messages on the server and synchronises them across devices. SMTP sends email, and POP usually downloads messages and removes them from the server.
7. A user receives an email that appears to be from their bank asking them to click a link and enter their password on a website that looks real but is fake. What type of attack is this?
Answer: Phishing. Phishing is a form of social engineering: fake messages trick people into giving away personal details. Staff training and spam filters help prevent it.
8. Which of these is a utility program rather than a function of the operating system?
Answer: Defragmentation software. Defragmentation is a utility: it reorganises files on a magnetic hard drive so they are stored in contiguous blocks. The other three are core operating system functions.
9. A student guesses a teacher's password and logs in to change their own marks. Which law have they broken?
Answer: Computer Misuse Act 1990. The Computer Misuse Act 1990 makes it an offence to access computer material without authorisation, and to do so with intent to commit further offences or to modify data.
10. A binary search looks for 31 in the sorted list [3, 8, 12, 19, 25, 31, 40]. Which items are compared with 31, in order?
Answer: 19, 31. The middle item of 7 is the 4th, 19. 31 > 19, so the search keeps [25, 31, 40]. Its middle item is 31, a match. Only 2 comparisons; the first option is a linear search.
11. The list [5, 2, 7, 1] is sorted into ascending order with a bubble sort. What is the list after the first pass?
Answer: 2, 5, 1, 7. Compare 5 and 2: swap → 2, 5, 7, 1. Compare 5 and 7: no swap. Compare 7 and 1: swap → 2, 5, 1, 7. One pass moves the largest value to the end; the list is not yet sorted.
12. A program sets total = 0, then runs the loop: for i = 1 to 4 ... total = total + i * 2 ... next i. Finally it runs print(total). What is output?
Answer: 20. Trace it: i = 1, total = 2; i = 2, total = 6; i = 3, total = 12; i = 4, total = 20. In OCR Exam Reference Language 'for i = 1 to 4' includes 4.
13. What is output by print(17 DIV 5 + 17 MOD 5)?
Answer: 5. DIV gives the whole number part of the division: 17 DIV 5 = 3. MOD gives the remainder: 17 MOD 5 = 2. 3 + 2 = 5.
14. For P = (A AND B) OR NOT C, which inputs make P equal to 0?
Answer: A = 1, B = 0, C = 1. P is 0 only if (A AND B) is 0 and NOT C is 0, so C must be 1 and A and B can't both be 1. A = 1, B = 0, C = 1 gives 0 OR 0 = 0. Each other row gives P = 1.
15. Which statement describes an interpreter?
Answer: It translates and runs the code one line at a time, stopping when it reaches an error. An interpreter translates and executes one line at a time, which helps debugging, but the program needs the interpreter every time it runs. A compiler translates the whole program into an executable file.

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Exam guide

GCSE Computer Science exam guide (2027): GCSE Computer Science is assessed by two exams at the end of Year 11, with no coursework. This guide follows OCR J277, the most common specification, and compares AQA 8525 and Pearson Edexcel 1CP2, which are structured differently. It covers what is on each paper, how the programming questions work, how grades are set and how to revise.

GCSE Computer Science exam FAQ

How many questions are on the GCSE Computer Science exam?

OCR J277: 2 written papers, 80 marks each (160 marks in total). AQA and Edexcel also set 2 papers with different lengths, with a time limit of 3 hours in total (2 × 1 hour 30 minutes). Format: written exams, no calculator. not tiered. in paper 2 section b you write or refine algorithms in ocr exam reference language or a high-level language you know.

What is the passing score for GCSE Computer Science?

Grade 4 is a standard pass and grade 5 a strong pass. Boundaries are set after every exam series, so aim for 70% in practice.

How much does the GCSE Computer Science exam cost?

No fee for school and college students (the school pays). Private candidates pay the exam centre; fees vary by centre. School and college students don't pay exam fees themselves. Private candidates pay the exam centre, and fees vary by centre and board.

Which languages is the GCSE Computer Science exam offered in?

English.

Where do I take the GCSE Computer Science exam?

At your school or college, or as a private candidate at an exam centre that accepts them.

Is this GCSE Computer Science practice test free?

Yes. The 15-question practice test on this page is free, with an explanation for every answer and no signup. A free account also unlocks the complete study notes for the first topic. The full GCSE Computer Science prep is Premium at £29 a month for this exam.

What's in the premium GCSE Computer Science prep?

3,000 practice questions organised topic by topic (Systems Architecture, Memory and Storage: 450; Data Representation: 425; Networks and Network Security: 425; Systems Software and Ethical, Legal and Environmental Issues: 425; Algorithms: 425; Programming Fundamentals and Robust Programs: 425; Boolean Logic and Programming Languages: 425), 6 full-length timed mock exams of 277 questions, 800 flashcards and 60 comprehensive key notes split across all 7 topics, plus a mistakes bank and the Readiness Score.

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Exam details are summarised from the exam boards' published specifications available in November 2026. the exam boards changes formats and fees, so confirm with OCR, AQA and Pearson Edexcel before you book. Kennington College is not affiliated with any exam board or with Ofqual.

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