The Cambridge IGCSE Computer Science (0478) May/June 2026 papers and mark schemes are out, and they’re free. Both papers, 0478/12 and 0478/22, can be downloaded and printed on the Tutopiya Learning Portal. Below is a breakdown of what each paper tested and how the mark scheme credited written answers, pseudocode and the long programming question, taken from the papers themselves.

Key points from the 2026 0478 papers

• Paper 2 had 30 marks of algorithm writing and fixing. There was a 6-mark validation algorithm, a 5-mark “not found” extension to a search and a 15-mark program, plus a 4-mark error-correction task.
• Number systems were worth 10 marks on Paper 1: number bases, two’s complement for a positive and a negative temperature, why hexadecimal is used, and three sets of hexadecimal conversions.
• Paper 1 was built around real contexts: a smartwatch, a video streaming service, a flower-identifying app and a vending machine. Generic textbook answers often missed the context the scheme wanted.
• Data handling linked the two papers. Paper 1 covered parity, encryption and compression; Paper 2 covered validation, files, a database table and SQL.
• Neither paper allows a calculator, so practise conversions and trace tables by hand.

All May/June 2026 0478 papers

Paper	Code	Duration	Marks	What it tests
Paper 1 Computer Systems	0478/12	1 hour 45 minutes	75	Data representation, transmission, hardware, software, the internet, cyber security, emerging technologies
Paper 2 Algorithms, Programming and Logic	0478/22	1 hour 45 minutes	75	Algorithm design, pseudocode, programming, databases, Boolean logic

Timings and marks are taken from the front cover of each 2026 paper. Each paper comes with its official Cambridge mark scheme. For the full list of syllabus content, see the Cambridge IGCSE Computer Science 0478 syllabus.

Which variant is this? Cambridge sets different versions of each paper (variants) for different time zones. The papers here are variant 2: 0478/12 and 0478/22. All variants cover the same syllabus at the same difficulty, so variant 2 is just as good for practice as the one your school sat.

Download the 0478 May/June 2026 papers →

What came up in 0478 Paper 2 (Algorithms, Programming and Logic), May/June 2026?

Paper 2 had ten questions worth 75 marks. The last question alone was worth 15 marks, a fifth of the paper.

Question	Topic	Marks
1	Pseudocode statements used for iteration (multiple choice)	1
2	The data type for a single character (multiple choice)	1
3	Validation: presence check, check digit, the purpose of a format check with an example, a 6-mark algorithm that accepts 15 whole numbers into an array	11
4	The coding and testing stages of the program development life cycle	6
5	A search of a 2D array of account IDs and names: find and correct four errors, name the algorithm, add a “not found” message	10
6	A flowchart that counts letters next to each other that match: complete a trace table for three words, state its purpose	7
7	Why data is stored in a file, pseudocode to read a line from a text file	5
8	Draw a logic circuit from a NOT, OR, XOR and NAND expression, complete its truth table	9
9	A car parts database table: choose data types, complete an SQL query for brake pads, explain why one field is redundant	10
10	A program to store 365 days of rainfall and output the total in centimetres, the mean, the dry days, the longest dry run and a drought warning	15

What made it hard: Question 10 asked for the longest run of days in a row with no rain. Totals and counts are routine, but tracking a running count and a maximum inside one loop is a step up. Question 5(c) also asked you to say where new lines go without rewriting the algorithm.

What came up in 0478 Paper 1 (Computer Systems)?

Paper 1 had seven questions worth 75 marks. Question 3, on a video streaming service, was worth 22 marks.

Question	Topic	Marks
1	A smartwatch: the microphone as an input device, the bit, number bases, two’s complement for 32 and −14, sensors	6
2	The CPU: its role, registers, how the MAR and MDR are used in the fetch stage, what a 3 GHz clock speed means	8
3	A video streaming service: why hexadecimal is used, three sets of conversions, packet structure and the router’s role, magnetic and solid-state storage, lossless and lossy compression	22
4	An odd parity byte check, why it can miss an error, other error detection methods, encryption, keys and ciphertext	10
5	Cyber security threats in a term and description table, how access levels help stop an attack	10
6	A flower-identifying app: images in binary, how AI can improve identification, cloud storage pros and cons	10
7	A vending machine program: low-level languages, the assembler, reasons to use low-level code, functions of an IDE	9

Watch for: the 4-mark question on how lossless compression works, Question 3(g)(iii). The scheme wanted a named method such as run-length encoding and an explanation of how repeated frames or pixels are found and recorded.

How the 0478 May/June 2026 mark scheme gives marks

Reading the two 2026 mark schemes together shows how examiners credit pseudocode, programs and short answers.

1. The 15-mark program is marked with two level grids. Paper 2 Question 10 was marked best fit against AO2 (up to 9 marks, bands 0, 1–3, 4–6 and 7–9) and AO3 (up to 6 marks, bands 0, 1–2, 3–4 and 5–6). The top AO2 band needs techniques that cover every requirement and data structures that store all the data. The top AO3 band needs a fully commented program with meaningful names throughout that logically does every task. The scheme lists three requirement groups: input and storage, the calculations, and the outputs with the drought check.

2. Minor syntax errors are ignored; missing logic is not. The grids ignore minor syntax errors, and you may use pseudocode or a programming language. What moves you down a band is a requirement you didn’t attempt, such as forgetting the rounding or the drought message.

3. Short algorithms are marked point by point. Paper 2 Question 3(c) gave one mark each for a loop for 15 inputs, the input, a test for a whole number, re-input until it is whole, storing in the right array element, and at least two messages. The scheme accepted MOD, DIV or ROUND to test for a whole number. Declarations were not needed, and case was ignored.

4. Say where your code goes. In Paper 2 Question 5(c) the marks were for a flag set to FALSE before the loop, set to TRUE where the ID is found, and checked after the loop. If you gave no location, your marks were capped. A version that replaced the FOR loop with a WHILE loop could also earn full marks.

5. Truth tables and trace tables have partial credit. Question 8(b) gave 4 marks for all eight outputs correct, 3 for six or seven, 2 for four or five and 1 for two or three. The trace table in Question 6(a) gave a mark per correct column. If your counts were wrong, the OUTPUT column could still score as follow through.

6. SQL and file code must use the given names. In Question 9(b), field names had to match the table, but the SELECT fields could be in any order. A space in a field name was penalised once, and small slips like “break pads” were ignored. In Question 7(b), you got one mark each for declaring a variable, opening Names.txt for reading, reading the line and closing the file.

7. “First answer” and “too vague” rules decide the short marks. Many Paper 1 parts say “mark first answer given”, so extra answers don’t help. Ticking more than one box scores zero. In Question 1(d), motion, sound, touch and heart rate sensors were “TV” (too vague), and describing a sensor instead of naming it was rejected. In Question 6(b), “it can learn and adapt” was “NE” (not enough) on its own.

8. Leading zeros and precise wording matter. The two’s complement answers in Paper 1 Question 1(c) needed all eight bits, leading zeros included. Hex-to-binary answers in Question 3(b) lost a mark only once for missing leading zeros. In Question 7(a), saying a low-level language is “understood” by the computer or “uses mnemonics” was not accepted.

Which papers should you sit?

0478 has no Core or Extended tiers. Every candidate sits both Paper 1 and Paper 2, each worth 75 marks and lasting 1 hour 45 minutes.

How to use the 2026 papers as a mock

1. Keep them for last. Use older 0478 papers for topic practice and save May/June 2026 for a full mock two to four weeks before your exam.
2. Sit each paper in one timed block without a calculator. Do the conversions and the truth table by hand, as on exam day.
3. Write Question 10 on paper, then type it. Run your program with a short test array to check the dry-run logic, then mark the paper version against the AO2 and AO3 grids.
4. Mark strictly with the mark scheme. Give a mark only when your answer contains the point in the scheme, and check the “TV” and “NE” notes.
5. Rewrite your weakest answers. Fix every algorithm that lost marks and add comments and meaningful names, since AO3 rewards both.

More IGCSE Computer Science resources

• IGCSE Computer Science 0478 past papers (all years)
• IGCSE past papers 2026: all subjects

🔍 Looking for a specific past paper? Use our free Past Paper Finder to search by subject, year and exam board.

Need help with a 0478 topic? Book a free trial lesson with an IGCSE Computer Science tutor →

Frequently asked questions

Are the 0478 May/June 2026 past papers free? +

Yes. Both question papers (0478/12 and 0478/22) and their official mark schemes are free to download and print on the Tutopiya Learning Portal.

What came up in 0478 Paper 2 May/June 2026? +

Paper 2 (0478/22) covered validation checks and a 6-mark validation algorithm, the coding and testing stages of the development life cycle, fixing a linear search on a 2D array, a flowchart trace table, reading from a text file, a logic circuit and truth table, a database with SQL, and a 15-mark rainfall statistics program.

How is the 15-mark program question in 0478 Paper 2 marked? +

It uses two level grids marked on a best-fit basis. AO2 (up to 9 marks) rewards the programming techniques and data structures you use, and AO3 (up to 6 marks) rewards comments, meaningful names, logical order and how fully the program meets the requirements. Minor syntax errors are ignored.

What topics came up in 0478 Paper 1 May/June 2026? +

Paper 1 (0478/12) covered two's complement, CPU registers and clock speed, hexadecimal conversions, packet switching, storage and compression, parity checks and encryption, cyber security threats and access levels, images in binary and AI, cloud storage, and low-level languages and IDEs.

Why can't I find 0478/21 or 0478/23 for 2026? +

Only variant 2 of the May/June 2026 papers is on the portal at the moment. Cambridge sets different variants for different time zones; variants 1 and 3 test the same syllabus in the same format, so variant 2 prepares you just as well.

When will the October/November 2026 0478 papers be available? +

Cambridge usually releases the October/November papers in the new year. We add them to the Learning Portal once they are published.

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