How to prepare

IAT

IISER Aptitude Test. Run by The Joint Admissions Committee of the Indian Institutes of Science Education and Research (IISERs). IAT 2026 was organised by IISER Berhampur..

The exam: A 3-hour computer-based test of 60 multiple-choice questions, 15 each in Biology, Chemistry, Mathematics and Physics, for 240 marks.
Opens: The only way into the 5-year BS-MS and the 4-year BS and B.Tech programmes at the seven IISERs (Berhampur, Bhopal, Kolkata, Mohali, Pune, Thiruvananthapuram, Tirupati), and one of two ways into IISc Bengaluru's 4-year BS (Research); IIT Madras BS, IIT Guwahati BS in Biomedical Science and Engineering, IACS Kolkata and IIEST Shibpur also use it, each with its own separate application.

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Your plan, step by step

Now to March 2027 (rest of Class 11)
Keep all four subjects alive
IAT gives Biology, Chemistry, Mathematics and Physics 15 questions each. A PCM student must still learn basic Biology from the NCERT books, and a PCB student must still do Class 11 Mathematics. Read NCERT in all four, and solve the NCERT exercises and NCERT Exemplar problems.
April to June 2027 (summer before Class 12)
Fix your weakest subject
Revise Class 11 and give most of the summer to the subject you are weakest in, because each subject is a quarter of the marks. Practise questions that need thinking, not just recall.
July to December 2027 (Class 12)
Class 12 NCERT and past papers
Study Class 12 with school. If you also prepare for JEE or NEET, most of that work counts for IAT; add the missing fourth subject. From October 2027, solve one past IAT paper or full mock a week under a 3-hour timer on a screen.
January to March 2028 (boards)
Boards first, IAT habit kept
You need 60 per cent in Class 12 (55 per cent for SC, ST, PwD) to be eligible, so do not risk your boards. Keep one IAT practice session a week.
April to early June 2028
Full mocks and the official mock
Take two full mocks a week, including the official mock on iiseradmission.in when it is posted. Practise with the on-screen calculator style. Learn when to skip: with minus 1 for a wrong answer, blind guessing does not pay.
After the result
Fill preferences carefully
The list of IISER programmes you prefer is filled only after the result. You are never offered a programme you did not list. If you also want IISc BS or IIT Madras BS, apply to them separately on their own sites.

This plan is advice from the author, not an official schedule. Adjust it to your school and your pace.

What the exam testsPapers, marks, marking and the syllabus

A 3-hour computer-based test of 60 multiple-choice questions, 15 each in Biology, Chemistry, Mathematics and Physics, for 240 marks. Four marks for a right answer, minus one for a wrong one. All four subjects carry equal weight.

Computer-based test (CBT) only, at centres across India. (IAT 2026 brochure)
60 questions: 15 Biology, 15 Chemistry, 15 Mathematics, 15 Physics. Each has one correct answer.
Duration 180 minutes (3 hours).
Marking: +4 for a correct answer, minus 1 for a wrong answer, 0 if left blank. Maximum 240.
The question paper is in English and Hindi.
An on-screen, non-programmable scientific calculator is provided; you may not bring your own. A rough pad is given and collected after the test.
Not every candidate gets a rank. A rank cut-off is announced, and a rank does not guarantee a seat.
Seats for 2026 (tentative): 2,343 in total, 2,043 in BS-MS across the seven IISERs and 300 in BS and B.Tech programmes at IISER Bhopal and IISER Tirupati.

When. Early June. IAT 2026 was held on 7 June 2026; applications ran from 5 March to 13 April 2026 (IAT 2026 brochure). IAT 2027 and 2028 dates have not been announced.

Syllabus. The IAT 2026 brochure prints a topic-by-topic syllabus for Biology, Chemistry, Mathematics and Physics. The topics match the Class 11 and 12 school syllabus, and coaching and news sites describe it as following the rationalised NCERT syllabus. Read the brochure's own list, not a coaching copy. (IAT 2026 brochure, Syllabi section)

Source: IISER Aptitude Test (IAT) 2026 Information Brochure Source: IAT 2026 Information Brochure, Syllabi

Study materialFree official material first, then books

Free and official

IISER admission websiteOfficial
The brochure, syllabus, dates, official mock test and every update. The only site to trust for IAT news.
IAT 2026 Information BrochureOfficial
The full pattern, eligibility, seat matrix and topic-wise syllabus in one PDF.
NCERT textbooksOfficial
Free official Class 11 and 12 books in all four IAT subjects.
SATHEE (Ministry of Education and IIT Kanpur)Official
Free JEE and NEET material; between them they cover all four IAT subjects. SATHEE does not advertise an IAT course, so use it for subject practice.
IISc BS (Research) admissionsOfficial
Eligibility, selection process and past closing ranks for IISc's BS, which takes IAT scores.

Books students commonly use

Commonly used, not endorsed. Finish the free official material first.

NCERT Physics, Chemistry, Mathematics and Biology, Class 11 and 12 by NCERT
The base in all four subjects. Commonly used, not endorsed.
Concepts of Physics (Vol 1 and 2) by H.C. Verma
Physics concepts and problems. Commonly used, not endorsed.
Understanding Physics series by D.C. Pandey
More Physics practice. Commonly used, not endorsed.
Concise Inorganic Chemistry by J.D. Lee
Inorganic chemistry depth. Commonly used, not endorsed.
Inorganic Chemistry by O.P. Tandon
Chemistry practice. Commonly used, not endorsed.
Problems in Calculus of One Variable by I.A. Maron
Calculus practice for stronger maths students. Commonly used, not endorsed.
Objective Biology for NEET (Vol 1 and 2) by Trueman's
Biology MCQs after NCERT. Commonly used, not endorsed.
Objective NCERT at your Fingertips by MTG Editorial Board
Chapter-wise NCERT-based MCQs. Commonly used, not endorsed.

Source: CollegeDekho: Best books for IISER Aptitude Test (not official)

Coaching: do you need it?Your options, how to choose, red flags

Self-study with free material

Free: NCERT books, the official brochure and mock, SATHEE

Most students. IAT tests school-level science and maths, so steady NCERT work in all four subjects plus past papers is often enough.

JEE or NEET coaching you already attend, plus self-study for the fourth subject

Varies

Students already in JEE or NEET coaching. That covers three of the four subjects; add Biology (for PCM) or Mathematics (for PCB) on your own.

IAT-focused online or classroom course

Varies. SciAstra's own page, checked 27 September 2026, listed its 'Vikram 3.0 Batch 2027' for Class 12 at Rs 42,000 after a discount from Rs 50,000.

Students who want a course built around IAT, NEST and similar science tests. Helps least if you are already strong in all four subjects.

How to choose a coaching centre

Ask whether the course teaches all four subjects equally, since IAT gives each 15 questions.
Ask to see a sample mock and check that it has 60 questions, 3 hours and +4, minus 1 marking, as in the official brochure.
Get the fee, refund policy and payment schedule in writing. The Ministry of Education's 2024 guidelines ask centres to publish fees and refund rules.
For classroom courses, ask who the counsellor is, whether batches are split by marks, and where the helpline is displayed, as the Supreme Court's July 2025 directions require.
Check that classes do not eat into school; you need 60 per cent in Class 12 to be eligible.

Red flags

A promise of a guaranteed IISER seat or rank.
Pressure to pay a full year upfront with no written refund policy.
Very large batches with no way to ask doubts.
Topper claims that do not say which course the topper took.
Advice to drop a subject entirely. IAT marks all four equally.

Names families usually consider

SciAstra. Focuses on IAT, NEST, IISc, ISI and CMI entrances. Its own site lists online batches and offline centres in Noida, Delhi, Bengaluru and Pune, and the Vikram 3.0 Batch 2027 at Rs 42,000 (discounted from Rs 50,000) when checked on 27 September 2026. Source: SciAstra: IAT and NEST courses
National JEE and NEET chains (Allen, Aakash, Physics Wallah and others). Students often use these for three of the four subjects. No IAT-specific course from them was verified.
Listed so you know the names, not ranked or endorsed. Visit, ask the questions above, and compare in writing.

Mocks and the last monthsPractice tests, final months, common mistakes

The IAT 2026 brochure said official mock tests would be posted on iiseradmission.in; take it as soon as it appears. Past IAT papers are hosted on several coaching and publisher sites; whether the IISERs publish them officially could not be confirmed. Solve at least the last three to five years under a 3-hour timer.

Take the official mock on iiseradmission.in as soon as it is posted, and use the same screen layout in your own practice.
Do two full 3-hour mocks a week and spend as long again checking every mistake.
Fix your weakest subject first: moving it from 20 to 40 marks is easier than moving your best from 50 to 60.
Keep an error notebook and re-read it weekly.
Do not neglect boards; the 60 per cent rule can cancel a good IAT rank.

Common mistakes

Dropping Biology (PCM students) or Mathematics (PCB students), when each is a quarter of the paper.
Guessing wildly despite minus 1 for a wrong answer.
Forgetting to fill a full preference list after the result; unlisted programmes are never offered.
Assuming IAT counts for IISc or IIT Madras automatically; they need a separate application.
Relying on coaching copies of the syllabus instead of the official brochure.

Who can sitAttempts, age, marks and subjects

Class 12 passed in 2024, 2025 or 2026, or appearing in 2026, from a board recognised by COBSE. Those who passed in 2023 or earlier could not sit IAT 2026. So a student gets the year of Class 12 plus the next two years, if the rule stays the same. (2026 brochure)
An improvement exam does not change your passing year.
For the BS-MS at all IISERs you must have taken at least three of Biology, Chemistry, Mathematics and Physics in Class 12.
Mathematics in Class 12 is compulsory for the BS-MS in Computational and Data Sciences (IISER Kolkata), B.Tech (IISER Bhopal), BS Economic Sciences (IISER Bhopal) and BS Economic and Statistical Sciences (IISER Tirupati).
Class 12 marks: at least 60 per cent in aggregate, counting all subjects, or 55 per cent for SC, ST and PwD candidates.
Application fee 2026: Rs 2,000 (General, EWS, OBC, OBC-NCL) and Rs 1,000 (SC, ST, PwD, Kashmiri Migrant). Not refundable.
No age limit or attempt count is stated; the passing-year rule is what limits attempts.
IISc BS (Research) 2026 took students through JEE Advanced or IAT only. It needed Physics, Chemistry and Mathematics as main Class 12 subjects and first class or 60 per cent (pass class for SC and ST). Total intake 125, including 20 supernumerary seats for women and 5 for foreign nationals.

Source: IAT 2026 Information Brochure, Eligibility Criteria

This exam leads to

Research science and mathematics

Want a plan for your own situation?

Tell Raahi your class, your marks and how many hours you have.

Plan my IAT preparation

Sources, checked 27 September 2026

Rules change every year. Confirm each detail on the official site before you register or pay.