Cambridge O Level Computer Science (2210) Past Papers: Grade Thresholds and Examiner Report Notes

This page is a guide to Cambridge O Level Computer Science (2210) past papers for the June and November series from June 2023 to June 2026. For each series you get the grade thresholds and a short summary of where candidates lost marks. The thresholds are copied from Cambridge’s grade-threshold documents, and the examiner notes are our own summaries of Cambridge’s Principal Examiner Reports for Teachers. We do not host any papers: every paper, mark scheme and report comes from Cambridge.

Where to get the official papers

• Cambridge O Level Computer Science (2210) syllabus page
• Cambridge O Level Computer Science (2210) past papers page

Cambridge publishes recent papers, mark schemes, examiner reports and grade thresholds on the syllabus’s past-papers page; older series are available to schools through the School Support Hub.

Use the three documents together. Sit the paper under timed conditions first. Then mark it with the mark scheme, which shows what earned credit. Finally, read the examiner report (or our notes below) to see why other candidates lost marks on the same questions.

The current 2210 syllabus is for exams in 2026, 2027 and 2028, so the June 2026 papers were set on it. Papers from June 2023 to November 2025 were set for earlier exam years. Check the syllabus version on the paper’s front cover against the current syllabus before you rely on a question.

Series index

Series	Papers (components) examined	Examiner report notes	Grade thresholds
June 2026	11, 12, 21, 22	Yes	Yes
November 2025	12, 13, 22, 23	Yes	Yes
June 2025	11, 12, 21, 22	Yes	Yes
November 2024	12, 13, 22, 23	Yes	Yes
June 2024	11, 12, 21, 22	Yes	Yes
November 2023	12, 13, 22, 23	Yes	Yes
June 2023	11, 12, 21, 22	Yes	Yes

Earlier series are on Cambridge’s past-papers page and are not summarised here.

Papers 11, 12 and 13 are the Computer Systems papers. Papers 21, 22 and 23 are the Algorithms, Programming and Logic papers.

What examiners keep saying

These are the mistakes that come up again and again, grouped by the syllabus’s own topics.

Data representation

• Binary addition: working it out in denary and converting back, or leaving out the carries, so the method and any overflow are not shown. (June 2023, November 2023, November 2024, June 2025, November 2025, June 2026)
• Two’s complement: putting a minus sign or a leading 1 in front of the positive pattern, reading it as unsigned, or flipping bits without adding 1. (June 2024, November 2024, June 2025, November 2025, June 2026)
• Fixed-width binary and hex: dropping leading zeros, getting the letter digits wrong, or converting a two-digit hex number to binary as one value instead of digit by digit. (June 2025, November 2025, June 2026)
• Storage units: dividing by 1000 instead of 1024, using the wrong multiplier, or giving bytes when bits were asked for. (June 2024, June 2025, June 2026)
• Sound and compression: confusing sample rate with sample resolution, calling all compression permanent data loss, or describing compression generically or for the wrong kind of file instead of the one in the question. (June 2023, November 2023, November 2024, June 2025, June 2026)

Data transmission

• Serial transmission described as sending packets one after another, when it sends data one bit at a time. (June 2024, June 2026)
• Error detection: positive and negative ARQ mixed up, checksum and check digit swapped, vague accounts of checksums, parity or check digits, and “odd” or “even” written when the parity bit itself was asked for. (November 2023, June 2024, November 2024, June 2025, June 2026)
• Encryption treated as something that stops data being stolen or a hack happening. (June 2024, November 2024, November 2025)

Hardware

• Fetch-decode-execute cycle: wrong registers at each stage, the wrong stage drawn, decoding left out of the control unit’s role, and the accumulator said to do the calculating. (June 2024, November 2024, June 2025, November 2025, June 2026)
• Storage media mislabelled: a hard disk called optical, an optical device called magnetic, and secondary storage assumed to sit outside the computer. (June 2024, November 2025)

Software

• Listing an operating system’s or IDE’s functions when its purpose, or examples of system software, were asked for, or defining a function by repeating its name. (November 2023, June 2024, November 2024, June 2025, June 2026)

The internet and its uses

• Process diagrams that are decorative or missing a key step: pharming and DDoS with no annotation, interception without packet sniffing, a page request routed from DNS to the web server, SSL without certificate checks. (June 2023, November 2023, November 2024, June 2026)

Automated and emerging technologies

• Defining AI, machine learning, an expert system or an automated system in general terms instead of showing how it works in the scenario given. This appears in every series we hold. (June 2023, November 2023, June 2024, November 2024, June 2025, November 2025, June 2026)

Algorithm design and problem-solving

• Verification and validation confused: verification thought to prove data is correct, or validation checks named when a verification check was asked for. (November 2023, November 2024, June 2025)
• Test data: extreme and boundary data confused, a test type named instead of a value, or boundary tests without an accepted and rejected pair. (June 2023, November 2023, November 2024)
• Trace tables stopped early, with uninitialised totals, quotation marks in outputs or entries after the loop should end. (November 2023, June 2024, November 2024, June 2025, November 2025)

Programming

• Real program code in pseudocode answers: Python syntax, FLOAT for REAL, non-syllabus CASE or file-handling commands, “text” as a data type. (June 2023, June 2024, November 2024, June 2025, November 2025, June 2026)
• Validating input with a single IF instead of a loop that asks again until the data is valid. (November 2023, June 2025, November 2025, June 2026)
• Procedures and functions: a header written when a call was wanted, CALL left out, no parameter type, or no RETURN in a function. (June 2024, November 2025, June 2026)

Databases

• SQL: text values in WHERE without quotation marks, numbers quoted or given units, and punctuation added to query output. (June 2024, November 2024, June 2025, November 2025, June 2026)

Exam technique the reports repeat

• Use precise technical terms and apply every answer to the device or scenario in the question. (every series; June 2025 also warns against repeating facts the question already gives)
• Show all working in binary arithmetic, including every carry, even when the question is really about overflow. (June 2023, November 2023, November 2024, June 2025, November 2025, June 2026)
• Match the command word. An explain question needs how or why in words, not bare pseudocode or a one-line definition. (November 2023, June 2024, November 2024, June 2025, June 2026)
• Answer the exact request: the base asked for, bits or bytes, examples or functions, the incorrect statement when that is what is wanted. (June 2024, November 2025, June 2026)
• Learn the syllabus pseudocode and use it whenever pseudocode is asked for; draw flowcharts with arrowheads and logic gates as the syllabus shows them. (June 2023, November 2023, June 2024, November 2025, June 2026)
• In the extended program, read the whole scenario first, use the arrays given, initialise variables, and add comments, prompts and output messages. (June 2023, November 2023, June 2024, November 2024, November 2025, June 2026)

June 2026

The Computer Systems papers asked about number conversions, binary addition and overflow, two’s complement, storage units, the fetch-decode-execute cycle, devices, transmission and parity, encryption, packets, compression, translators, cyber security and AI. Recall and conversions were good, but the report wants sharper technical language, accurate step-by-step processes and answers that use the scenario. The programming papers covered validation and verification, library routines, file handling, functions, loops, sorting and searching, flowcharts, logic, database data types, SQL and the extended program. The best scripts wrote exact syllabus syntax and answered at the depth the command word asked for. Weaker ones slipped real code into pseudocode and mixed up programming and database data types.

Where marks were lost

• Paper 11: dividing by 1000 instead of 1024 for storage units, dropping leading zeros, and showing overflow without the carries.
• Paper 11: naming the MDR as the first register used, or saying the CIR does its work during execute.
• Paper 12: flipping the bits for two’s complement without adding 1, and writing “odd” or “even” when a parity bit was asked for.
• Paper 21: FLOAT used for REAL, a Python-style not-equals sign, and UCASE or SUBSTRING results never assigned to a variable.
• Paper 22: in the extended program, an integer where a real was needed, totals left uninitialised and a read one element past the end of the array.

Grade thresholds – June 2026

Components	Max	A*	A	B	C	D	E
11, 21	150	117	93	69	46	39	32
12, 22	150	120	94	68	43	36	29

Not shown: 1 further route(s) in the official table (staged entries that carry marks from an earlier series, or other special routes). See the official document.

Official documents: past papers, mark schemes and examiner report

November 2025

The Computer Systems papers focused on number bases, including fixed-width binary, the limits of hex, two’s complement and shifts. They also covered CPU operation, interrupts, storage media, packets, internet technologies, cyber security, translators and AI in a scenario. Once again the report asks for technical terms used in context. The programming papers tested procedures and CALL, validation with string handling, trace tables, array initialisation, logic circuits, primary keys, SQL and extended programs built on random numbers. Good scripts stuck to syllabus pseudocode and the data structures given. Weaker scripts repeated a term’s name instead of explaining it, stayed generic and validated input with a single IF.

Where marks were lost

• Paper 12: giving how many values a set of bits can store, or a single digit, when the largest value was asked for.
• Paper 12: describing how an optical disc is read when the question asked how data is written, and little grasp of how a queued interrupt is serviced.
• Paper 13: writing a negative two’s complement number as the positive pattern with a 1 in front, and hex-to-binary nibbles without four digits.
• Paper 22: CALL left out when the procedure is used, even after a correct input statement.
• Paper 23: validating with an IF instead of a loop that asks for the data again, and ties for the top result not handled in the extended task.

Grade thresholds – November 2025

Components	Max	A*	A	B	C	D	E
12, 22	150	104	84	64	45	37	29
13, 23	150	104	84	64	45	37	29

Official documents: past papers, mark schemes and examiner report

June 2025

Computer Systems questions this series centred on data representation, from conversions and storage units to two’s complement, images and compression. They also covered CPU design, memory and virtual memory, transmission, error detection and emerging technologies. The programming papers tested validation and verification, test data, string functions, MOD and DIV, functions with parameters, trace tables, logic, SQL and an extended task on a 2D array. Candidates who used the published pseudocode accurately and wrote about the scenario did well. Weaker answers were generic, repeated the question back, and could not explain checksums, virtual memory or SSL.

Where marks were lost

• Paper 11: converting a two-digit hex number to binary as if it were one denary value, instead of digit by digit, and using the wrong multiplier between storage units.
• Paper 11: saying a faster clock runs cycles at the same time, or that the accumulator holds the calculation rather than its result.
• Paper 12: giving the positive bit pattern when the two’s complement of a negative number was asked for.
• Paper 21: MOD and DIV written with the wrong syntax, and “text” used as a data type instead of a syllabus type.
• Paper 21: validating with a single IF rather than a loop, and keeping only one name when several shared the top score.
• Paper 22: describing verification as making data correct, or mixing it up with validation.

Grade thresholds – June 2025

Components	Max	A*	A	B	C	D	E
11, 21	150	116	94	72	50	42	35
12, 22	150	123	100	77	54	47	41

Official documents: past papers, mark schemes and examiner report

November 2024

Theory questions covered data units, binary and hex, two’s complement, compression and character sets, error detection and encryption. They also asked about CPU registers and the stages of the fetch-decode-execute cycle, cloud storage, URLs, how a web page is fetched, and uses of AI and machine learning. The programming papers tested flowcharts, bubble sort, verification, trace tables, boundary data, string and file handling, SQL output and two array-based extended programs. Strong answers dealt with the exact point and the scenario. Weak ones gave a definition when a use or role was wanted, compared only one side, and ignored indexing, loops or initialisation.

Where marks were lost

• Paper 12: saying the accumulator carries out calculations, and showing a page request travelling from the DNS server to the web server.
• Paper 12: describing a barcode scanner instead of how a check digit finds an error.
• Paper 13: comparing symmetric and asymmetric encryption by describing only one, and believing encryption stops data being stolen.
• Paper 22: struggling to explain why a bubble sort with a flag and a shrinking inner loop is efficient, and naming validation checks when verification was asked.
• Paper 23: boundary tests without an accepted and rejected pair, and inclusive limits written as strict inequalities.
• Paper 23: a bubble sort with only one loop, and arrays used without an index.

Grade thresholds – November 2024

Components	Max	A*	A	B	C	D	E
12, 22	150	107	88	69	51	42	33
13, 23	150	109	88	67	46	38	31

Official documents: past papers, mark schemes and examiner report

June 2024

The theory papers drew on hex, shifts, two’s complement and binary units, packet structure, serial transmission, error detection, storage types, the fetch stage, system software and firmware, robots and AI, and network security. The programming papers covered validation, procedures and library routines, CASE, file handling, totalling and counting, trace tables, logic expressions, SQL and a large task on a 2D array. Scripts that used exact terms and applied them to the device or scenario scored well. Weaker scripts misread the request, for example working in binary when hex was asked, or giving functions instead of examples. Some held basic misconceptions about storage and transmission, or wrote non-syllabus pseudocode.

Where marks were lost

• Paper 11: finding a negative two’s complement value by putting a minus sign in front of an unsigned conversion, and using 1000 for binary prefix units.
• Paper 11: describing serial transmission as packets sent one at a time instead of bits, and calling a hard disk optical.
• Paper 12: muddling the registers in the fetch sequence, and swapping checksum and check digit.
• Paper 21: writing a procedure header when a call with parameters was wanted, and text values in WHERE without quotation marks.
• Paper 22: starting a logic expression with the output name, and declaring variables in the final program when told not to, which earns nothing (any needed initialisation must still be shown).

Grade thresholds – June 2024

Components	Max	A*	A	B	C	D	E
11, 21	150	107	84	61	38	32	26
12, 22	150	120	95	70	45	37	29

Official documents: past papers, mark schemes and examiner report

November 2023

Theory questions in this series focused on number systems and binary arithmetic, CPU architecture, how sound and images are stored, transmission and error detection, cyber threats, storage and automated or AI systems. The programming papers covered validation and verification, test data, trace tables, logic circuits, SQL, file handling and an extended program on a 2D array. Conversions, gate symbols and trace tables were mostly sound. The best scripts showed full working and gave technical explanations tied to the context. Weaker ones offered vague one-line definitions, switched to denary to avoid binary addition, ignored the scenario or wrote pseudocode outside the syllabus format.

Where marks were lost

• Paper 12: shifting binary in the wrong direction, and doing binary addition in denary so overflow was never shown.
• Paper 12: confusing sample resolution with sample rate, and leaving packet sniffing out of an interception diagram.
• Paper 13: listing what an operating system does when its purpose was asked, and mixing positive and negative ARQ.
• Paper 22: thinking verification proves data is correct, rather than that it was not changed on entry, and counting the header row as a record.
• Paper 23: validation missing its loop, AND conditions with the variable left off one side, and an extended task that used only one dimension of the 2D array.

Grade thresholds – November 2023

Components	Max	A*	A	B	C	D	E
12, 22	150	105	85	65	46	37	29
13, 23	150	105	85	65	46	37	29

Official documents: past papers, mark schemes and examiner report

June 2023

The theory papers ranged over data representation, transmission, storage, translators, cyber security and automated systems. The programming papers tested validation and testing, trace tables, string handling, logic gates, simple databases and an extended program. Number conversions and transmission methods were strong. What set strong scripts apart was precise vocabulary applied to the question’s scenario. Weaker scripts described systems in general terms and mixed up paired ideas, such as sound and image sampling, lossy and lossless, or high- and low-level languages. In the programming papers they wrote real code where pseudocode was wanted, or missed a last step such as rounding.

Where marks were lost

• Paper 11: binary addition done through denary or without carries, and sample rate and resolution confused with image terms.
• Paper 11: packet switching described without independent routing and reassembly in the right order.
• Paper 12: a compiler explained by its benefits, not how it works, and the advantages of high- and low-level languages swapped.
• Paper 21: extreme and boundary test data confused, and the output not rounded in the extended program.
• Paper 22: adding range checks nobody asked for to a double-entry verification routine.

Grade thresholds – June 2023

Components	Max	A*	A	B	C	D	E
11, 21	150	102	82	62	42	35	28
11, 22	150	104	83	62	42	35	29
12, 22	150	109	86	63	40	33	27

Official documents: past papers, mark schemes and examiner report

How to use this page

1. Find your starting point with the free 2210 diagnostic (every free diagnostic is listed on the diagnostics page), then tick off what you know on the 2210 checklist.
2. Download one paper and its mark scheme from Cambridge. Sit it timed, in one go, with no notes.
3. Mark it strictly with the mark scheme. Note every question where you lost marks and which syllabus topic it belongs to.
4. Read the section above for that series, then the “What examiners keep saying” list. Check whether your lost marks match a known trap. Use the command words guide when an explain or describe question went wrong.
5. Fix the weak topics with the notes and practice on the O Level Computer Science hub, then try the 2210 self-check question bank.
6. Re-test with a paper from a different series and compare your mark with that series’ thresholds. For the latest series on our flagship syllabuses, see our grade thresholds page.
7. Plan your remaining papers against your exam dates on the exam calendar. If you want a teacher to go through your scripts, book a free trial class.

About these notes

The grade thresholds are copied from Cambridge’s grade-threshold tables, and the examiner notes are written in our own words from Cambridge’s Principal Examiner Reports for Teachers for the series listed above. Thresholds change every series and must never be used to predict future ones. If you spot an error, please report a correction.