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If you enjoy science more than engineering, the Indian Institutes of Science Education and Research (IISERs) are worth a close look. Admission runs through their own entrance test, the IISER Aptitude Test (IAT), and it differs from JEE and NEET in one important way: it tests all four sciences. This post sets out what the official IISER pages say about the test, works through its marking, and gives a preparation plan that fits alongside your other exams.
What is the IAT, and who uses it?
The government has set up IISERs at Berhampur, Bhopal, Kolkata, Mohali, Pune, Thiruvananthapuram and Tirupati. The official eligibility page for 2026 says admission to IISERs is "exclusively through the IISER Aptitude Test". The main programme is the five-year BS-MS dual degree, and some IISERs also run four-year BS and B.Tech. programmes.
Other institutes also used IAT 2026 scores. The IAT for other institutes page lists the BS programme at IIT Madras, the BS in Biomedical Science and Engineering at IIT Guwahati, the BS (Research) at IISc Bengaluru, the BS-MS at IACS Kolkata, and the BS-MS at IIEST Shibpur. Each needs a separate application on that institute's own site, in addition to the IAT.
What was the IAT 2026 pattern?
From the official IAT page:
Computer-based test on Sunday, 7 June 2026, 9:00 am to 12:00 noon.
60 multiple-choice questions, 15 each from biology, chemistry, mathematics and physics, each with only one correct answer.
+4 for a correct answer, −1 for a wrong answer, 0 for unanswered. Maximum 240.
Not every candidate gets a rank, and a rank alone does not mean an offer.
The syllabus page says the test "will broadly follow the rationalized NCERT syllabus for 2025-2026", and the detailed IAT 2026 syllabus PDF lists topics chapter by chapter. The 2026 dates page shows the application window ran from 5 March to 13 April 2026, so the cycle for each year starts in spring. These are 2026 details; check the site for the current year's notice.
Who is eligible?
For 2026, the eligibility page asked for Class XII passed in 2024 or 2025, or appearing in 2026, from a COBSE-recognised board, with at least three of biology, chemistry, mathematics and physics. It also asked for at least 60% aggregate in Class XII (55% for SC, ST and PwD candidates), calculated over all subjects. Some programmes, such as the B.Tech. at IISER Bhopal and the Computational and Data Sciences BS-MS at IISER Kolkata, require mathematics in Class XII.
How does the marking work out?
Three minutes per question is the average: 180 minutes for 60 questions.
Example. A student answers 44 questions, gets 38 right and 6 wrong, and leaves 16 blank.
Score = 38 × 4 − 6 × 1 = 152 − 6 = 146 out of 240.
Now consider guessing. If a question has four options and you guess at random, the expected mark is (1/4)(+4) + (3/4)(−1) = +0.25. If you can rule out two options, it rises to (1/2)(+4) + (1/2)(−1) = +1.5. This is only an average over many questions, and a wrong guess still costs a mark. Our post on negative marking and when to guess explains how to decide.
How should you prepare?
Since IAT follows NCERT, your main preparation is the same as for boards. The extra work is the fourth subject.
Map the gap. Print the IAT 2026 syllabus PDF and tick topics you have studied. A JEE aspirant usually has to add the whole biology column; a NEET aspirant, the mathematics column.
Build the fourth subject from NCERT. Two to three hours a week from January of Class 12 lets you read the Class 11 and 12 NCERT books for that subject once and test yourself on each chapter.
Try the official mock. The mock test page links to a practice test in the real interface. Take it once early, to see the format, and once in the last fortnight.
Practise mixed sets. Make sets of 20 questions, five from each subject, timed at one hour.
Plan around other exams. In 2026, IAT was on 7 June. Put this year's IAT date next to your JEE or NEET dates so your revision does not peak too early.
If you are starting the fourth subject from scratch and do not know where to begin, Fermi's AI tutor works out what you already know and builds a plan for the session, so the first hour has a clear next step. For deciding between science and engineering more broadly, see our guide to choosing a stream after Class 10.
This week, download the IAT syllabus PDF and mark every topic in your weakest of the four subjects.
