IAT 2026 Exam is soon to be conducted on June 7, 2026, at multiple exam centres across the nation from 9 am to 12 pm. Since only a few days are left for the candidates applied for the BS-MS/BS/BTech degree courses offered by IISERs, IACS, IISc and IITs. Test Takers IAT 2026 Preparation now requires a strategic approach that is strongly aligned with past year trends and exam analysis.

Over the years, IAT has evolved into a highly competitive national-level entrance exam conducted in a computer-based format, comprising 60 multiple-choice questions from Physics, Chemistry, Mathematics, and Biology, with equal weightage across subjects. IISER 2026 Preparation with past year trend analysis reveals that the exam consistently emphasises conceptual clarity, interdisciplinary thinking, and application-based problem-solving rather than rote memorisation.

IAT 2026 Past Trends also indicate recurring high-weightage topics and predictable question distribution patterns, making previous year papers an essential resource for preparation. Therefore, a well-planned IAT 2026 strategy must combine syllabus coverage, rigorous practice of PYQs, and mock test analysis to effectively adapt to these evolving trends and maximise performance.

The SciAstra academic team, based on previous years’ trends and in-depth research, has identified subject-wise high-priority chapters and analysed frequently asked concepts. Read this blog for complete information.

IISER 2026 Exam Highlights

Candidates taking the IISER entrance exam for the academic session 2026-2027 can check out the exam highlights from the following details:

Particulars

Details

Exam Name

IISER Aptitude Test (IAT) 2026

Conducting Body

One of the IISER

Exam Level

National Level

Exam Mode

Computer-Based Test (CBT)

Courses Offered

5-year Integrated BS–MS, 4-year BS, and BS–BTech Dual Degree

Participating Institutes

IISERs, IISc Bangalore, IIT Madras (as applicable)

Exam Frequency

Once a year

Medium of Question Paper

English

Subjects Covered

Physics, Chemistry, Mathematics, Biology

Question Type

Multiple Choice Questions (MCQs)

Total Questions

60 (15 questions per subject)

Exam Duration

180 minutes (3 hours)

Marking Scheme

+4 for each correct answer, −1 for each incorrect answer

Total Marks

240

Eligibility

Class 12 (or equivalent) with Science subjects

Selection Process

IAT Score → Counselling → Seat Allotment

Official Website

iiseradmission.in

Why Past Year Trend Analysis is Crucial for IAT 2026

Most aspirants make the mistake of studying everything equally. However, IAT is a pattern-driven exam, where certain topics consistently carry more weight.

Benefits of Trend Analysis

  • Identifies high-weightage topics

  • Helps in understanding difficulty level shifts

  • Improves time allocation strategy

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IAT 2026 Preparation with Past Year Trend Analysis (2017-2025)

While the overall structure has remained stable, the difficulty level often fluctuates between moderate and challenging, with certain sections, especially Biology and Chemistry, which frequently feature NCERT-driven yet analytical questions, while Mathematics and Physics test deeper logical reasoning. Additionally, increasing competition, with a rising number of applicants each year, has made score differences highly sensitive to accuracy and negative marking.

Candidates can check out the subject-wise IAT 2026 Preparation with past year trend analysis from here:

IISER 2026 Biology Past Year Trend Analysis

An analysis of previous years’ IAT papers shows that the topics consistently include Human Physiology, Plant Physiology, and Ecology.

Candidates can check out the IISER 2026 biology past year trend analysis from here:

Biology

Section

Chapters

2017

2018

2019

2020

2021

2022

2023

2024

2025

Diversity

1

1

1

1

1

1

-

1

1

Morphology and Anatomy

1

-

2

1

2

1

2

1

-

Cell Biology

and Biomolecules

Cell Biology

2

2

1

1

1

1

1

-

1

Biomolecules

1

-

1

-

-

-

2

-

1

Plant Physiology

2

-

1

2

3

2

1

2

2

Human Physiology

1

4

2

3

1

3

1

3

3

Molecular Biology

Genetics

1

1

1

-

-

3

1

1

2

Molecular Biology

-

1

1

1

1

1

1

1

2

Evolution

1

-

1

1

1

1

1

-

-

Human Health

Human Health & Disease

and Microbes in Human Welfare

2

2

1

1

1

-

1

1

-

Reproduction

1

-

1

1

-

-

2

2

1

Biotechnology

1

2

1

1

2

1

1

2

1

Ecology

1

2

1

2

2

1

1

1

1

Also Read: How to Prepare for IAT 2026 Biology Section

IISER 2026 Chemistry Past Year Trend Analysis

Chemistry in the IISER Aptitude Test (IAT) 2026 focuses on conceptual understanding across Physical, Organic, and Inorganic Chemistry. Candidates can check out the IAT 2026 Chemistry past year trend analysis from here:

Chemistry

Section

Chapters

2017

2018

2019

2020

2021

2022

2023

2024

2025

Physical

Some Basic Concept of Chemistry

1

-

-

-

-

-

-

-

-

Atomic Structure

2

1

-

1

1

1

1

1

1

Thermodynamics

1

1

1

1

1

1

2

1

1

Equilibrium

-

-

1

-

-

1

-

-

-

Solution

-

1

-

-

-

1

1

1

-

Electrochemistry

1

1

1

1

1

1

-

1

2

Chemical Kinetics

1

-

1

1

2

-

-

1

1

Inorganic

Periodicity

-

-

-

1

-

1

-

1

1

Chemical Bonding

1

-

2

1

3

1

1

2

2

Coordination

3

-

2

2

2

2

-

2

1

d- & f- block

-

2

1

-

-

-

-

-

1

Organic

Introduction To Organic And GOC

-

-

1

-

2

1

2

1

-

Hydrocarbon

-

2

1

1

-

1

1

1

-

Alcohol Phenol and Ether

-

-

-

-

-

1

-

1

-

Haloalkanes and Haloarenes

-

1

-

-

1

2

1

-

-

Aldehyde Ketone and Carboxylic Acids

4

1

1

3

2

-

-

-

5

Amines

1

2

1

-

-

1

-

1

-

Biomolecules

-

-

1

1

-

-

1

1

-

Also Read: How to Prepare for IAT 2026 Chemistry Section 

IISER 2026 Physics Past Year Trend Analysis

 Analysis of previous year papers shows that questions are primarily numerical and application-based, with a strong focus on fundamentals. Check out the list of important topics that were asked by the officials here:

Physics

Section

Chapters

2017

2018

2019

2020

2021

2022

2023

2024

2025

Mechanics

Kinematics

-

-

-

-

-

-

1

1

-

Laws Of Motion

-

1

-

2

-

-

-

-

2

Work Power Energy

1

1

-

-

-

-

-

-

1

System Of Particles

-

1

1

1

1

2

-

-

-

Rotation

-

1

1

1

2

3

2

2

1

Oscillation

Simple Harmonic Motion

-

1

1

-

1

1

-

3

Waves

1

-

-

-

1

-

1

-

2

Mechanical Properties of Matter

Properties Of Matter

1

-

-

-

-

-

-

-

-

Fluid Mechanics

-

1

-

-

-

1

-

1

-

Kinetic Theory of Gases

-

-

2

1

1

-

-

1

-

Thermodynamics

1

2

2

1

1

1

1

1

-

Gravitation

1

1

1

-

-

-

1

-

-

Electricity

Electrostatics

1

1

2

2

1

2

2

1

1

Capacitors

-

-

2

-

2

1

-

1

-

Current

2

1

-

2

-

-

2

-

1

Electromagnetism

Magnetism

1

-

1

-

-

-

1

1

2

Electromagnetic Induction

1

1

-

1

1

-

1

-

-

Alternating Current

2

-

-

-

-

1

-

1

-

Electromagnetic Wave

-

1

-

1

1

-

-

-

-

Optics

Ray Optics

1

-

1

1

-

1

2

-

2

Wave Optics

-

-

-

-

1

-

-

-

-

Modern Physics

Modern Physics

1

1

-

2

2

2

-

2

3

Semiconductors

1

1

1

-

-

-

1

-

-

Also Read: IAT 2026 Books

IISER 2026 Mathematics Past Year Trend Analysis

Check out the previous years' trends of the questions from the Mathematics section from here:

Mathematics

Section

Chapters

2017

2018

2019

2020

2021

2022

2023

2024

2025

Algebra

Set Theory

-

-

1

-

-

1

-

-

1

Quadratic Equation

1

-

1

1

-

-

1

-

-

Complex number

1

1

-

-

1

1

-

1

1

Sequence & Series

1

1

1

-

-

-

-

1

1

Binomial Theorem

1

-

-

-

-

-

-

1

1

Matrices & Determinants

1

2

1

2

2

1

1

1

1

Mathematical induction

-

1

-

-

-

-

-

-

-

Differential Calculus

Basic Maths

-

-

-

-

-

-

1

-

-

Relations

-

-

-

-

-

1

-

-

-

Functions

2

3

1

1

1

1

1

1

1

Application of Derivatives

2

1

-

1

-

2

2

1

1

Continuity & Differentiability

1

-

-

1

1

-

1

1

2

Limits

-

1

1

1

1

-

-

-

-

Probability and Statistics

Probability

1

1

1

1

1

1

1

1

1

Statistics

-

-

1

1

1

-

1

-

-

Permutation & Combination

-

-

-

-

-

-

-

-

1

Integral Calculus

Differential Equation

1

-

-

-

-

1

1

1

1

Indefinite & Definite Integral

1

1

1

2

2

2

1

1

1

Area under Curve

-

-

1

2

2

1

1

1

-

Geometry

Straight Lines

1

1

2

1

1

1

1

2

-

Conic Sections

-

1

-

-

-

-

1

-

1

Circles

-

-

1

-

-

1

1

-

-

Vectors

-

1

1

-

-

1

-

1

1

3D geometry

-

-

-

1

1

-

-

1

-

Trigonometry

Trigonometric Equation

1

-

1

-

1

-

-

-

-

Also Read: How to Prepare for IAT and NEST 2026 Together

IAT Past Year Trend Analysis (2020–2025)

Let’s break down how the exam has evolved over the years.

Difficulty Level Trends

Year

Overall Difficulty

Physics

Chemistry

Mathematics

Biology

2020

Moderate

Moderate

Easy-Moderate

Moderate

Easy

2021

Moderate

Moderate

Moderate

Moderate-High

Easy

2022

Moderate-Difficult

Difficult

Moderate

Moderate

Easy

2023

Moderate

Moderate

Easy-Moderate

Moderate

Easy

2024

Moderate-Difficult

Difficult

Moderate

Moderate-High

Easy

2025

Moderate

Moderate

Moderate

Moderate

Easy-Moderate

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