Checked 30 September 2026. Links point to gate2027.iitm.ac.in and were checked on 30 September 2026. The files themselves do not change; the host could move them.
The organising institute for GATE 2027, IIT Madras, hosts the official GATE CS question papers and answer keys from 2021 to 2026 on its download page. This guide links each file directly, explains why 2024, 2025 and 2026 each have two sets, and shows what each set actually contained, so you can decide which papers to use when.
We do not re-host the PDFs. Every link below goes to the official site, and every count on this page comes from those files. Where the count is ours (question types per set, topics per set) we say so.
Counts are ours, from the official papers and keys.
Find a paper
Official GATE CS paper finder
Pick a year and a set. The links go straight to the question paper and answer key PDFs on the official GATE 2027 website; nothing is re-hosted here.
Links checked on 30 September 2026. If one stops working, the same files are listed on gate2027.iitm.ac.in/download.
The same links as a table, for readers on a simplified view:
| Year | Set | Organiser | Sitting | Question paper | Key |
|---|---|---|---|---|---|
| 2026 | CS-1 | IIT Guwahati | Sun 8 Feb 2026, forenoon | gate2027.iitm.ac.in/static/doc/download/2026/QPs/CS1.pdf | gate2027.iitm.ac.in/static/doc/download/2026/Keys/CS1_Keys.pdf |
| 2026 | CS-2 | IIT Guwahati | Sun 8 Feb 2026, afternoon | gate2027.iitm.ac.in/static/doc/download/2026/QPs/CS2.pdf | gate2027.iitm.ac.in/static/doc/download/2026/Keys/CS2_Keys.pdf |
| 2025 | CS-1 | IIT Roorkee | Sat 1 Feb 2025, forenoon | gate2027.iitm.ac.in/static/doc/download/2025/CS12025.pdf | gate2027.iitm.ac.in/static/doc/download/2025_Key/CS1_Keys.pdf |
| 2025 | CS-2 | IIT Roorkee | Sat 1 Feb 2025, afternoon | gate2027.iitm.ac.in/static/doc/download/2025/CS22025.pdf | gate2027.iitm.ac.in/static/doc/download/2025_Key/CS2_Keys.pdf |
| 2024 | CS-1 | IISc Bangalore | Session 5 (date not in the files we hold) | gate2027.iitm.ac.in/static/doc/download/2024/CS124S5.pdf | gate2027.iitm.ac.in/static/doc/download/2024/CS1FinalAnswerKey.pdf |
| 2024 | CS-2 | IISc Bangalore | Session 6 (date not in the files we hold) | gate2027.iitm.ac.in/static/doc/download/2024/CS224S6.pdf | gate2027.iitm.ac.in/static/doc/download/2024/CS2FinalAnswerKey.pdf |
| 2023 | CS | IIT Kanpur | single file on the download page | gate2027.iitm.ac.in/static/doc/download/2023/cs_2023.pdf | gate2027.iitm.ac.in/static/doc/download/Answer_keys2023/CS_ANS_GATE2023.pdf |
| 2022 | CS | not stated on the download page | single file on the download page | gate2027.iitm.ac.in/static/doc/download/2022/cs_2022.pdf | gate2027.iitm.ac.in/static/doc/download/Answer_keys2022/cs_2022.pdf |
| 2021 | CS | not stated on the download page | single file on the download page (key file is named "merged") | gate2027.iitm.ac.in/static/doc/download/2021/cs_2021.pdf | gate2027.iitm.ac.in/static/doc/download/Answer_keys2021/cs_merged_2021.pdf |
Everything above is listed on the official GATE 2027 download page. The download page carries CS files from 2021 onwards only.
Why there are two sets a year
GATE CS has been held in two sessions every year from 2024 to 2026, because too many candidates sit it for one session. In 2026 both sessions were on Sunday 8 February (CS-1 in the forenoon, CS-2 in the afternoon); in 2025 both were on Saturday 1 February. The 2024 keys name the sessions only as Session 5 and Session 6, and we do not hold an official file that gives their date.
Each candidate writes one set. Because the sets differ, raw marks are normalised before scores are calculated: the brochure maps each session's marks using that session's top-0.1% average and its mean plus one standard deviation. The GATE 2027 brochure says only that some papers may be held in more than one session and does not yet name them; CS is likely to be one again, but that is not yet stated, and the CS paper date for 2027 has not been published. The exam days are 6, 7, 13, 14, 20 and 21 February 2027.
What each set contained
Question types in the subject part (questions 11 to 65), counted from the official keys. The last two columns are marks, out of 85.
| Set | MCQ 1-mark / 2-mark | MSQ 1-mark / 2-mark | NAT 1-mark / 2-mark | MCQ marks (negative marking) | MSQ + NAT marks (no negative) |
|---|---|---|---|---|---|
| 2024 CS-1 | 11 / 8 | 10 / 10 | 4 / 12 | 27 | 58 |
| 2024 CS-2 | 12 / 10 | 11 / 7 | 2 / 13 | 32 | 53 |
| 2025 CS-1 | 10 / 10 | 8 / 5 | 7 / 15 | 30 | 55 |
| 2025 CS-2 | 16 / 6 | 5 / 13 | 4 / 11 | 28 | 57 |
| 2026 CS-1 | 8 / 10 | 13 / 11 | 4 / 9 | 28 | 57 |
| 2026 CS-2 | 14 / 11 | 5 / 6 | 6 / 13 | 36 | 49 |
Our count from the official keys. 2026 CS-2 was the most MCQ-heavy set of the six.
Two sets of the same year can feel like different exams. 2026 CS-1 had 24 MSQs and only 18 MCQs; 2026 CS-2, written the same afternoon, had 11 MSQs and 25 MCQs. If you practise only one set of a year, practise the other as a separate mock rather than assuming you have seen that year.
Marks per section, set by set
| Section | 2024 CS-1 | 2024 CS-2 | 2025 CS-1 | 2025 CS-2 | 2026 CS-1 | 2026 CS-2 |
|---|---|---|---|---|---|---|
| Engineering Mathematics | 14 | 13 | 15 | 12 | 15 | 13 |
| Programming & Data Structures | 8 | 10 | 9 | 12 | 12 | 10 |
| Computer Organization & Architecture | 10 | 10 | 8 | 9 | 9 | 9 |
| Algorithms | 7 | 6 | 9 | 8 | 8 | 10 |
| Operating System | 8 | 8 | 8 | 7 | 8 | 9 |
| Computer Networks | 9 | 9 | 6 | 6 | 8 | 9 |
| Databases | 8 | 8 | 8 | 9 | 6 | 6 |
| Digital Logic | 6 | 6 | 8 | 9 | 8 | 7 |
| Theory of Computation | 7 | 7 | 8 | 7 | 6 | 6 |
| Compiler Design | 8 | 8 | 6 | 6 | 5 | 6 |
Section marks are our classification of each question into the official syllabus sections; the full method and the 24 borderline items are in the weightage guide.
See GATE CS topic-wise weightage for the question counts, question types by section and the classification rule.
Old questions the 2027 syllabus no longer covers
The 2027 Computer Networks syllabus is shorter than the 2026 one. Reading the six sets against it, these questions rest mainly on topics the 2027 syllabus no longer lists. They are still useful for understanding, but a mock score that includes them slightly overstates the paper you will face.
| Set and question | Topic | Why it is now out of scope (our reading) |
|---|---|---|
| 2025 CS-1 Q16 (1 mark, MCQ) | Matching OSI layers to functions | OSI and TCP/IP protocol stacks are no longer listed |
| 2025 CS-2 Q16 (1 mark, MCQ) | ARP mapping, paired with a TCP piggybacking statement | ARP is no longer listed; the TCP half remains in scope |
| 2025 CS-2 Q18 (1 mark, MCQ) | Which protocol cannot appear in the IPv4 protocol field (ICMP, IGMP, OSPF, RIP) | ICMP and the IP support protocols are no longer listed |
| 2026 CS-2 Q22 (1 mark, MCQ) | Which protocol may broadcast (SMTP, FTP, DHCP, HTTP) | DHCP, SMTP and FTP are no longer listed |
| 2025 CS-2 Q23 (1 mark, MCQ) | IPv4 fragmentation of a UDP segment | Still in scope: fragmentation remains listed; only the 8-byte UDP header is a detail you would now need to be given |
| 2026 CS-2 Q43 | Cyclic redundancy check | Still in scope, under data link layer error detection |
Disk questions are a grey area. Three questions in the six sets were disk geometry or disk transfer-time calculations (2024 CS-1 Q54, 2024 CS-2 Q53, 2026 CS-1 Q59). "Secondary storage" is no longer named in the 2027 Computer Organization section, while Operating System still lists file systems and I/O scheduling. We would not call these removed; we would call them no longer named in COA, and keep practising them.
How to read a GATE CS answer key
Four things the key tells you, and one it does not
- MCQ: one letter. A wrong answer costs 1/3 of a mark on a 1-mark question and 2/3 on a 2-mark question.
- MSQ: one or more letters separated by semicolons, for example "A;C;D". You score only if you mark exactly that set; there is no partial credit and no negative marking.
- NAT: a range such as "260.20 to 261.20" (2025 CS-2 Q56). Any value inside the range scores. A range with equal ends, such as "13 to 13", means that exact value.
- MTA (marks to all): no question in the 2024, 2025 or 2026 CS keys is marked MTA. The 2023 key marks General Aptitude Q2 as MTA.
- Final or not: the 2024 keys are titled "Final Answer Key". The 2025 and 2026 files on the download page are titled "Answer Key", and the PDFs do not say whether they are the post-challenge versions.
Conflict noted: the key titles differ between years. We use the files as the organiser lists them for each year.
Should you guess? The negative-marking calculator
Pick the question type and how many of the four options you can confidently rule out. The calculator shows your expected marks from answering versus leaving it blank.
The calculator applies the official negative-marking rule to a four-option MCQ. The same arithmetic in words: a blind guess on a four-option MCQ has an expected value of exactly zero; ruling out one option makes the guess worth attempting on average; MSQ and NAT answers can never cost marks.
A sensible order for using the papers
| Stage | Papers | How |
|---|---|---|
| While learning a section | 2021, 2022 and 2023 | Solve that section's questions only, open book, straight after finishing the topic |
| After finishing the syllabus | 2024 CS-1 and CS-2 | Full timed mocks, three hours each, scored with the official key |
| Final six weeks | 2025 CS-1 and CS-2, then 2026 CS-1 and CS-2 | Full timed mocks; keep the newest pair for last |
| After each mock | The same set | Re-solve every wrong and every guessed question, then list the topics they came from |
Scoring a mock with the official key gives you raw marks. To see what those marks would have been worth as a GATE score and rank, use the calculator in the score guide; it uses the official formula and each year's official parameters. Remember that a two-set year is normalised, so a raw mark in one set is only an approximation of the score.
Convert a mock mark with the GATE CS marks-to-score calculator, or estimate a rank with the GATE CS rank predictor. For a review of the 2026 paper itself, see GATE CS exam analysis.
Practise it, don't just read it
Between full papers, a ten-question topic quiz is a quick way to check one section without spending three hours.
The ProSyllabus GATE CS library currently has 29 topic quizzes of ten questions each, covering programming and data structures, algorithms, operating systems, databases, computer networks, compiler design and theory of computation, each with a worked explanation. There are no quizzes yet for Engineering Mathematics or Computer Organization, and Digital Logic has only number systems, so use the official papers for those. One networks quiz is built on the OSI and TCP/IP stacks, which the 2027 syllabus no longer lists.
Where can I download official GATE CS previous year papers?
From the download page of the GATE 2027 website, gate2027.iitm.ac.in/download, run by IIT Madras. It lists CS question papers and answer keys for 2021 to 2026, with two sets each for 2024, 2025 and 2026.
Why does GATE CS have Set 1 and Set 2?
Because CS is held in two sessions. In 2026 both were on 8 February and in 2025 both on 1 February, forenoon and afternoon. Each candidate writes one set, and marks are normalised across the two before scores are calculated.
Are the GATE CS 2025 and 2026 answer keys final?
The files on the official download page for 2025 and 2026 are titled "Answer Key", while the 2024 files are titled "Final Answer Key". The PDFs do not state whether they are post-challenge versions.
Are old GATE CS networking questions still relevant for 2027?
Most are, but the 2027 syllabus no longer lists the OSI and TCP/IP stacks, ARP, DHCP, ICMP, UDP, SMTP, FTP or Email. Questions built on those topics, such as 2025 CS-1 Q16 on OSI layers and 2026 CS-2 Q22 on DHCP, fall outside the new syllabus.
Is there negative marking for MSQ and NAT in GATE CS?
No. Only MCQs carry negative marking: one third of a mark for a wrong 1-mark answer and two thirds for a wrong 2-mark answer. MSQ and NAT have no negative marking, and MSQ has no partial credit.
More in this series
- GATE CS topic-wise weightage, counted from six official sets
- GATE CS qualifying marks, score vs rank, with calculator
- GATE CS 2027 syllabus changes, section by section
- PSU recruitment through GATE CS 2027, from the notices
- GATE DA vs GATE CS: which paper to write
- GATE CS rank predictor
- GATE CS expected cut-off for top IITs
- GATE CS notice board: official updates
- GATE CS exam analysis
- GATE Computer Science complete guide
Sources
- official — GATE 2027 download page: previous papers and keys
- official — GATE 2026 CS-1 question paper
- official — GATE 2026 CS-1 Answer Key
- official — GATE 2026 CS-2 question paper
- official — GATE 2026 CS-2 Answer Key
- official — GATE 2025 CS-1 question paper
- official — GATE 2025 CS-1 Answer Key
- official — GATE 2025 CS-2 question paper
- official — GATE 2025 CS-2 Answer Key
- official — GATE 2024 CS-1 question paper
- official — GATE 2024 CS-1 Final Answer Key
- official — GATE 2024 CS-2 question paper
- official — GATE 2024 CS-2 Final Answer Key
- official — GATE 2023 CS question paper
- official — GATE 2023 CS answer key
- official — GATE 2027 Information Brochure, IIT Madras, revised 27 Sep 2026
- official — GATE 2027 CS syllabus (IIT Madras)
- official — GATE 2026 examination schedule (IIT Guwahati)
- official — GATE 2025 examination schedule (IIT Roorkee)
official = a document published by the conducting body. reported = a news or coaching site we could not check against an original. Where sources disagree this page says so rather than picking one.
