How to Start Preparations for IAT 2027: A Data-Backed Complete Roadmap
Who This Guide Is For: Class 12 students and droppers aiming for IISER IAT 2027, especially those starting their preparation journey from mid-2026.
Data Source: IAT papers from 2017 to 2025 (9 years) + IAT 2025 official counselling data.
Preparation Timeline: 12 months from June 2026 to May 2027.
The IISER Aptitude Test is one of the most intellectually demanding undergraduate entrance exams in India — and also one of the most misunderstood. Most aspirants prepare for it the wrong way. This guide corrects that, using real chapter-wise data from IAT 2017–2025 so you know exactly what to study, in what order, and to what depth.
1. Know the Exact Exam Pattern First
IAT is a Computer-Based Test (CBT) of 3 hours. The paper contains 60 questions divided equally across four subjects. Every correct answer carries +4 marks and every wrong answer carries −1 mark. The total is 240 marks. There is no sectional time limit — you can move freely across sections.
| Feature | Detail |
|---|---|
| Total Questions | 60 |
| Questions per Subject | 15 (Physics, Chemistry, Mathematics, Biology) |
| Marking Scheme | +4 for correct, −1 for incorrect |
| Total Marks | 240 |
| Duration | 3 Hours (180 minutes) |
| Exam Mode | Computer-Based Test (CBT) |
The syllabus is based on NCERT Class 11 and Class 12 PCMB. However, what NCERT teaches and what IAT actually tests are two different things. IAT emphasises conceptual depth, cross-topic reasoning, and application — not recall. This makes chapter-wise prioritisation essential.
Important: IAT does not follow a fixed chapter-wise weightage declared officially. The priority data below is derived from analysis of actual IAT papers from 2017 to 2025 — nine consecutive years of real exam data.
IAT 2025 Final Closing Ranks (Category-wise)
These are the final closing ranks from IAT 2025 counselling across all 9 rounds. Use them to understand the competitiveness of each IISER campus and to set realistic rank targets for IAT 2027.
| Institute | General | OBC-NCL | EWS | SC | ST |
|---|---|---|---|---|---|
| IISER Pune | 164-208 | 144-184 | 149-181 | 119-161 | 103-134 |
| IISER Kolkata | 145-173 | 131-151 | 133-145 | 122-138 | 94-131 |
| IISER Mohali | 137-165 | 115-169 | 128-141 | 112-131 | 98-124 |
| IISER Bhopal | 135-161 | 120-135 | 118-130 | 99-115 | 79-102 |
| IISER TVM | 132-170 | 122-139 | 102-123 | 84-120 | 73-105 |
| IISER Tirupati | 125-152 | 103-134 | 100-119 | 89-117 | 75-100 |
| IISER Berhampur | 111-134 | 102-131 | 95-114 | 80-112 | 77-103 |
Key Insights from Closing Rank Data
- IISER Pune remains the most competitive campus with General closing rank of 1,671
- IISER Kolkata CDS programme (rank 1,839) is more competitive than regular BS-MS (rank 4,758)
- IISER Bhopal B.Tech programmes (rank 3,169) attract strong interest
- IISER Berhampur and Tirupati have the highest closing ranks, making them accessible at lower ranks
- A difference of 1,000 rank positions can separate admission into different IISERs
2. Chapter-Wise Priority: What IAT Actually Tests
This is the most critical section of this guide. Below is a subject-wise breakdown of high-priority chapters based on 9-year IAT question data (2017–2025), with average questions per paper and key concepts to focus on.
Subject 1: Biology
Biology is a scoring section for PCB students and a manageable one for PCM students if approached right. Animal Physiology and Plant Physiology together account for nearly 40 percent of Biology questions historically.
Subject Overview:
- Total Questions: 15
- Total Marks: 60
- Average Difficulty: Moderate to High
- NCERT Dependency: Very High (80-85 percent)
| Chapter | Avg. Questions (2017-25) | Frequency | Key Concepts to Master |
|---|---|---|---|
| Animal Physiology | 2.2 | 9/9 | Digestive, circulatory and nervous systems; endocrine system; respiration and excretion |
| Plant Physiology | 1.8 | 9/9 | Photosynthesis mechanisms; xylem and phloem transport; plant hormones (auxins, gibberellins, cytokinins) |
| Biotechnology | 1.3 | 8/9 | Recombinant DNA technology; PCR; gel electrophoresis; agricultural and medical applications |
| Ecology | 1.3 | 8/9 | Ecosystem structure; food chains; biogeochemical cycles (carbon, nitrogen); population dynamics |
| Cell Biology | 1.2 | 8/9 | Cell organelles structure and function; membrane transport; enzymes and metabolism |
| Genetics | 1.1 | 8/9 | Mendelian inheritance patterns; DNA structure and replication; mutations; genetic disorders |
| Human Health and Disease | 1.0 | 7/9 | Immune system (antibody and cell-mediated); common diseases (cancer, AIDS); microbes in human welfare |
| Diversity of Life | 1.0 | 7/9 | Five kingdom classification; basic animal and plant kingdom characteristics |
| Molecular Biology | 0.7 | 5/9 | Transcription and translation; gene regulation (lac operon); RNA processing |
| Reproduction | 0.7 | 5/9 | Sexual reproduction in plants and humans; reproductive health |
| Evolution | 0.6 | 4/9 | Darwin's theory; natural selection mechanisms; speciation; evolutionary evidence |
| Biomolecules | 0.6 | 4/9 | Carbohydrates, proteins, lipids, nucleic acids; enzyme classification |
Subject 2: Chemistry
Chemistry has the most predictable chapter distribution of all four subjects. Coordination Chemistry, Chemical Bonding, Aldehydes/Ketones/Carboxylic Acids, Thermodynamics, and Electrochemistry together account for over 60 percent of Chemistry questions.
Subject Overview:
- Total Questions: 15
- Total Marks: 60
- Average Difficulty: Moderate
- Distribution Pattern: Highly Predictable
| Chapter | Avg. Questions (2017-25) | Frequency | Key Concepts to Master |
|---|---|---|---|
| Coordination Chemistry | 1.5 | 8/9 | Crystal Field Theory (octahedral and tetrahedral); isomerism (geometric, optical); colour and magnetism in complexes; spectrochemical series |
| Aldehydes, Ketones and Carboxylic Acids | 1.5 | 7/9 | Aldol condensation (cross aldol, intramolecular); Cannizzaro reaction; Grignard reagents; acidity of carboxylic acids (inductive and resonance effects) |
| Chemical Bonding | 1.3 | 8/9 | Molecular Orbital Theory (bond order, paramagnetism of O2); VSEPR theory (molecular shapes); hybridisation in homo/hetero diatomic molecules |
| Thermodynamics | 1.1 | 9/9 | First and second laws; P-V work (reversible and irreversible); Gibbs free energy (ΔG = ΔH - TΔS); spontaneity criteria; Hess's law |
| Electrochemistry | 1.1 | 9/9 | Electrochemical cells (galvanic and electrolytic); Nernst equation (temperature dependence); Kohlrausch's law; conductivity calculations |
| Hydrocarbons | 1.1 | 7/9 | Wurtz reaction; Markovnikov and anti-Markovnikov addition; alkyne reactions (hydration, hydrogenation); free radical halogenation |
| Atomic Structure | 1.0 | 7/9 | Bohr's model (energy, radius, velocity calculations); quantum numbers (n, l, m, s); hydrogen emission spectrum series |
| Chemical Kinetics | 0.9 | 6/9 | Rate law determination (initial rate method, integrated equations); Arrhenius equation (activation energy); graphical analysis |
| General Organic Chemistry | 0.8 | 6/9 | Inductive, mesomeric, hyperconjugation effects; carbocation stability order; reaction intermediates; organic reaction mechanisms |
| Amines | 0.8 | 5/9 | Basicity comparisons; diazotisation reactions; preparation methods (Gabriel phthalimide, Hoffmann degradation) |
| Periodic Properties | 0.7 | 5/9 | Periodic trends (atomic radius, ionisation energy, electronegativity, electron affinity); s/p/d/f block configurations |
| Solutions | 0.6 | 4/9 | Concentration terms (molarity, molality, mole fraction); colligative properties (boiling point elevation, freezing point depression); Raoult's law |
| Haloalkanes and Haloarenes | 0.6 | 4/9 | SN1 and SN2 mechanisms (stereochemistry, kinetics); elimination reactions (E1, E2); substitution vs elimination |
| Solid State | 0.4 | 3/9 | Unit cells (SCC, BCC, FCC); packing efficiency; voids; Bragg's law; defects in crystals |
| d- and f-Block Elements | 0.3 | 2/9 | Transition metal properties; KMnO4 and K2Cr2O7 reactions; lanthanide contraction |
Subject 3: Mathematics
Mathematics is the section that separates top rankers from the rest. Application of Derivatives alone accounts for approximately 16 percent of all Mathematics questions over 9 years — the single highest chapter share in any subject. Calculus (derivatives and integrals) combined with Matrices and Determinants forms the core of IAT Mathematics.
Subject Overview:
- Total Questions: 15
- Total Marks: 60
- Average Difficulty: High
- Rank Decider: Yes
| Chapter | Avg. Questions (2017-25) | Frequency | Key Concepts to Master | |
|---|---|---|---|---|
| Application of Derivatives | 1.8 | 9/9 | Maxima and minima (with applications in geometry, physics, economics); increasing/decreasing functions; tangents and normals; rate of change (related rates problems) | |
| Matrices and Determinants | 1.3 | 8/9 | Solving linear equations (Cramer's rule, matrix inversion); properties of determinants (row/column operations); inverse of a matrix; elementary transformations | |
| Functions | 1.2 | 8/9 | Types of functions (one-one, onto, bijective, even, odd, periodic); domain and range calculation; composite functions (fog, gof); inverse functions; graphical transformations | |
| Indefinite and Definite Integrals | 1.2 | 9/9 | Standard integral forms; substitution methods (trigonometric, algebraic); integration by parts (ILATE rule); definite integral properties (King's property, Leibniz rule) | |
| Coordinate Geometry | 1.2 | 8/9 | Straight lines (distance from point, angle between lines, family of lines); conic sections (parabola, ellipse, hyperbola, circle); tangent and normal conditions | |
| Probability | 0.7 | 5/9 | Bayes' theorem (reverse probability); total probability theorem (law of total probability); conditional probability (P(A | B) = P(A∩B)/P(B)); random variables |
| Sequence and Series | 0.7 | 5/9 | Arithmetic and Geometric progression sums; AM-GM inequality (applications in maxima-minima); special series (Σn, Σn², Σn³); infinite GP | |
| Complex Numbers | 0.6 | 5/9 | Algebra of complex numbers (addition, multiplication, division); polar form (Euler's representation); De Moivre's theorem (nth roots of unity); Argand plane geometry | |
| Quadratic Equations | 0.6 | 5/9 | Nature of roots (discriminant analysis); sum and product of roots; quadratic expressions (range, maxima, minima); common roots conditions | |
| Differential Equations | 0.6 | 4/9 | Order and degree; variable separable method; homogeneous differential equations; linear differential equations (dy/dx + Py = Q); integrating factor | |
| Continuity and Differentiability | 0.6 | 4/9 | Continuity conditions (left hand limit = right hand limit = value); differentiability (smoothness); L'Hopital's rule; Rolle's and Lagrange's theorems | |
| Vectors and 3D Geometry | 0.5 | 4/9 | Dot product and cross product (geometric interpretation); scalar triple product; equation of line and plane in 3D; shortest distance between skew lines | |
| Binomial Theorem | 0.4 | 3/9 | General term expansion; middle term; binomial coefficients (properties and sums); multinomial theorem basics | |
| Trigonometry | 0.2 | 2/9 | Trigonometric identities and equations; inverse trigonometric functions (principal values, properties); general solutions |
Subject 4: Physics
Physics in IAT is application-heavy. Rotation (moment of inertia, angular momentum, rolling motion) is the single most asked Physics chapter — averaging 1.6 questions per paper. Electrostatics and Modern Physics follow closely. Mechanics as a whole (Rotation plus Simple Harmonic Motion) is non-negotiable.
Subject Overview:
- Total Questions: 15
- Total Marks: 60
- Average Difficulty: High
- Most Dynamic Subject: Yes (pattern varies year to year)
| Chapter | Avg. Questions (2017-25) | Frequency | Key Concepts to Master |
|---|---|---|---|
| Rotation (System of Particles) | 1.6 | 8/9 | Moment of inertia calculation (rod, ring, disc, sphere); torque and angular acceleration (τ = Iα); angular momentum conservation (L = Iω); rolling motion (pure rolling condition v = Rω); parallel and perpendicular axis theorems |
| Electrostatics | 1.4 | 9/9 | Gauss's law applications (infinite line charge, infinite sheet, uniformly charged sphere); electric potential calculation (point charge, dipole); capacitor energy storage (U = ½CV²); dielectric effects |
| Modern Physics | 1.3 | 9/9 | Photoelectric effect (Einstein's equation KEmax = hν - φ); de Broglie wavelength (λ = h/p); radioactive decay law (N = N₀e^{-λt}); Bohr's model (energy levels, spectral series); nuclear binding energy |
| Thermodynamics | 1.1 | 9/9 | First law of thermodynamics (ΔU = Q - W); second law of thermodynamics; Carnot engine efficiency (η = 1 - T₂/T₁); P-V diagram analysis (isothermal, adiabatic, isobaric, isochoric processes) |
| Simple Harmonic Motion | 1.0 | 7/9 | Energy equations (KE = ½k(A² - x²), PE = ½kx²); spring-mass systems (series and parallel combinations); simple pendulum (T = 2π√(L/g)); compound pendulum; resonance |
| Magnetism | 1.0 | 7/9 | Biot-Savart law (magnetic field due to straight wire, circular loop, solenoid); Ampere's circuital law; force on current-carrying conductor (F = ILB sinθ); magnetic dipole moment; moving coil galvanometer |
| Ray Optics | 0.8 | 6/9 | Mirror formula (1/f = 1/v + 1/u) and magnification; lens formula (1/f = 1/v - 1/u) with sign conventions; total internal reflection (critical angle sin C = 1/n); prism deviation (δ = i + e - A); optical instruments |
| Capacitors | 0.8 | 6/9 | Capacitance calculation for parallel plate, spherical, cylindrical capacitors; series and parallel combinations; energy stored; dielectric constant and dielectric strength |
| Current Electricity | 0.8 | 6/9 | Ohm's law and resistance combinations (series, parallel, series-parallel); Kirchhoff's laws (junction and loop rule); Wheatstone bridge (balanced condition); potentiometer (EMF comparison); electrical power and energy |
| Electromagnetic Induction | 0.6 | 5/9 | Faraday's law (induced EMF = -dφ/dt); Lenz's law (direction of induced current); motional EMF (EMF = Blv); self and mutual inductance; energy stored in inductor (U = ½LI²) |
| Gravitation | 0.6 | 4/9 | Kepler's laws (orbital motion); gravitational potential energy (U = -GMm/r); orbital velocity and escape velocity (v_esc = √(2GM/R)); satellites (geostationary orbit) |
| Kinetic Theory of Gases | 0.6 | 5/9 | Ideal gas equation (PV = nRT); law of equipartition of energy; mean free path; Maxwell-Boltzmann distribution; degrees of freedom |
| Waves | 0.4 | 3/9 | Transverse and longitudinal waves; superposition principle; standing waves; beats; Doppler effect (source and observer motion) |
For PCM students preparing for IAT: Biology may feel unfamiliar, but nearly all high-average Biology chapters (Animal Physiology, Plant Physiology, Cell Biology, Ecology) are entirely conceptual and can be studied in 6-8 weeks from NCERT alone. Do not neglect them; 15 Biology questions at +4 marks each is 60 marks — equivalent to an entire subject.
3. Target Scores: What You Actually Need
IAT 2025 saw significantly higher closing ranks compared to 2024 — a clear sign of growing competition. Understanding where you need to score for each IISER is critical for setting realistic preparation benchmarks.
IAT 2025 Marks-Based Cutoffs (Actual)
| Institute | General | OBC-NCL | EWS | SC | ST |
|---|---|---|---|---|---|
| IISER Pune | 165-206 | 144-182 | 149-179 | 119-159 | 103-132 |
| IISER Kolkata | 145-171 | 131-149 | 133-143 | 122-135 | 94-129 |
| IISER Mohali | 137-163 | 115-167 | 128-139 | 112-128 | 98-122 |
| IISER Bhopal | 135-159 | 120-133 | 118-127 | 99-113 | 79-99 |
| IISER TVM | 132-167 | 122-137 | 102-121 | 84-117 | 73-103 |
| IISER Tirupati | 125-149 | 103-132 | 100-117 | 89-114 | 75-98 |
| IISER Berhampur | 111-132 | 102-129 | 95-112 | 80-110 | 77-101 |
For IAT 2027, expect these cutoffs to rise further. IAT 2025 General category marks needed for the safest IISER (Berhampur) were 105+. For IISER Pune you needed 165+ in General. Plan your preparation target accordingly aim for 175+ to have options across multiple IISERs.
IAT 2027 Projected Category-Wise Minimum Marks
4. The 12-Month Preparation Roadmap
With IAT 2027 approximately 12 months away from mid-2026, you have the ideal preparation window. The plan below is structured in four phases that build upon each other — do not skip ahead.
Phase 1: NCERT Foundation + Priority Chapter Coverage
Duration: June – September 2026 (4 months)
Primary Focus:
- Read every NCERT chapter carefully for all four subjects — not skimming, but reading for understanding. The IAT is built on NCERT; every question traces back to a concept in these books.
- Based on the priority tables above, identify your top 5 chapters per subject and begin deeper study of those.
- For PCM students, start Biology NCERT from Class 11 in this phase.
Weekly Target:
- Physics: 3-4 chapters
- Chemistry: 3-4 chapters
- Mathematics: 2-3 chapters
- Biology: 2-3 chapters (for PCM students)
Deliverables:
- Complete first reading of all NCERT textbooks
- Create chapter-wise notes for critical topics
- Solve 30-40 basic questions per chapter
Pro Tip: Do not skip chapters that seem unimportant from the trend data — IAT has surprised with low-average topics appearing in specific years. The trends show probability, not certainty.
Phase 2: Problem Practice + Previous Year Papers
Duration: October – January 2027 (4 months)
Primary Focus:
- Begin solving IAT previous year papers from 2017 onwards — there are 9 papers available. Do not rush them.
- Attempt one paper, then spend equal time analysing it. IAT questions are not JEE-style; they often involve multi-step reasoning or unusual applications of standard concepts.
- Strengthen your weakest subject with focused chapter-wise problem practice.
Weekly Target:
- 1 full-length IAT previous year paper (timed)
- 2-3 sectional tests per subject
- 100-150 quality problems across all subjects
Deliverables:
- Completed all 9 IAT previous year papers
- Maintain error log with classification (conceptual, silly, time, risk)
- Identify top 3 weak chapters per subject
Phase 3: Board Exams + Parallel IAT Revision
Duration: February – March 2027 (2 months)
Primary Focus:
- Class 12 boards will run through February and March. Do not abandon IAT preparation entirely.
- Since your conceptual foundation is already built in Phases 1 and 2, boards will largely reinforce IAT material.
- Keep 1 hour per day exclusively for IAT revision — review your notes, error log, and high-priority chapter summaries.
Weekly Target:
- Board exam preparation (primary)
- 1 hour daily IAT revision
- 1-2 subject-wise tests per week (optional)
Deliverables:
- Complete board examinations successfully
- Maintain IAT readiness without burnout
Important: Avoid starting any new IAT-specific material in this phase. Focus on revision and consolidation only.
Phase 4: Full-Length Mocks + Final Revision
Duration: April – May 2027 (6-8 weeks)
Primary Focus:
- This is your most intensive phase. Attempt at least 8-10 full-length timed mock tests under actual exam conditions — 3 hours, no interruptions.
- Analyse every mock thoroughly. By this stage you should be seeing your scores stabilise; track them and identify which chapters still cost you marks.
- In the final 10 days, stop all new learning and focus only on consolidation and confidence-building.
Weekly Target:
- 2-3 full-length mock tests
- 4-6 hours of mock analysis
- 2-3 hours of weak area revision
Deliverables:
- Consistent mock scores in target range (145+ for General)
- Error log cleared for repeat mistakes
- Confidence and exam temperament developed
5. Smart Preparation Principles That Actually Work for IAT
Principle 1: Understand Derivations, Do Not Just Memorise Results
IAT questions frequently test whether you understand where a formula comes from, not just what it is. In Physics, be able to derive key results like the mirror formula, lens formula, and expression for moment of inertia. In Chemistry, understand reaction mechanisms step by step rather than memorising products. In Mathematics, understand the geometric intuition behind algebraic results. This depth is what distinguishes IAT from other entrance examinations.
Principle 2: Do Not Attempt to Cover Everything Equally
The chapter-wise data above makes clear that IAT is not uniformly distributed. Application of Derivatives in Mathematics (1.8 questions per year on average), Coordination Chemistry (1.5), Aldehydes and Ketones (1.5), Rotation (1.6), Electrostatics (1.4), Animal Physiology (2.2), and Plant Physiology (1.8) — these chapters recur year after year with above-average question shares. Invest disproportionately in high-average chapters without completely neglecting the rest.
Principle 3: The Negative Marking Changes Your Approach Entirely
With −1 per wrong answer and +4 per correct answer, the break-even point is answering 1 in 5 questions correctly — which means random guessing is nearly neutral. But near-certain guessing (where you can eliminate 2-3 options confidently) has a strong positive expectation. In your mock tests, track your strike rate on attempted questions. Aim for above 85 percent accuracy on attempted questions rather than attempting all 60.
Principle 4: Previous Year Papers Are Your Primary Resource, Not Supplementary
IAT previous year papers from 2017 to 2025 are the single most important practice material. The examination has a consistent intellectual personality — certain question styles, certain types of reasoning, certain levels of depth recur. Solving all 9 papers carefully will make you intimately familiar with what the examination actually demands, which no textbook can replicate.
Principle 5: Maintain an Error Log and Revisit It Weekly
Track every mistake you make in practice and mock tests. Classify each error into one of four categories: conceptual error (re-learn the concept), silly mistake (create a checklist to catch these), time management error (practice speed drills), or risk error (learn when to skip). Revisit this log every weekend. This process alone can improve your score by 15-20 marks.
Principle 6: Simulate Real Exam Conditions for Mock Tests
Take your mock tests exactly as the real examination will be — at the same time of day (morning), in a quiet room, without any interruptions, with a timer visible. Do not pause, do not check your phone, do not take extra breaks. The psychological pressure of timed conditions is real; train for it.
6. Common Mistakes That Derail IAT Preparation
Mistake 1: Treating IAT Like JEE or NEET
IAT is neither JEE nor NEET. It has its own pattern, difficulty level, and question style. JEE Advanced is significantly more difficult in Mathematics and Physics but has no Biology. NEET has Biology but simpler Physics and Chemistry. IAT sits in the middle — moderate difficulty across all four subjects with emphasis on analytical thinking.
Solution: Use IAT-specific resources and previous year papers. Do not rely entirely on JEE or NEET materials.
Mistake 2: Neglecting One Subject Entirely
Many PCM students ignore Biology completely, thinking they can still qualify. But 15 Biology questions at +4 each is 60 marks. Even a score of 20 in Biology (5 correct out of 15) requires some preparation. Without any preparation, guessing yields approximately 12 marks (3 correct, 12 incorrect = 12 - 12 = 0).
Solution: Dedicate 6-8 weeks to Biology NCERT before Phase 2.
Mistake 3: Poor Time Allocation Across Sections
There is no sectional time limit in IAT. Students often spend 30 minutes on one difficult Physics question while leaving 5 easy Biology questions unattempted.
Solution: In mock tests, practice the strategy of completing all easy questions first across all subjects, then returning to difficult ones.
Mistake 4: Ignoring Mock Test Analysis
Taking a mock test is only 20 percent of the learning. The analysis is 80 percent. Students who take 20 mock tests without analysis improve less than those who take 5 mock tests with thorough analysis.
Solution: Spend 2-3 hours analysing every 3-hour mock test.
Mistake 5: Changing Strategy Too Late
In the final month before the examination, your preparation strategy should stabilise. Do not suddenly switch to new books, new resources, or new question types.
Solution: Finalise your resources and strategy by the end of Phase 2.
7. Reference Resources (by Subject)
The following references are widely recommended by IAT high-scorers and are calibrated to the examination's conceptual demands.
| Subject | Primary Resource | Supplementary Resource |
|---|---|---|
| Physics | NCERT Class 11 and 12 + H.C. Verma (Concepts of Physics Vol. 1 and 2) | D.C. Pandey (selected chapters on Rotation, Electrostatics, Modern Physics) |
| Chemistry | NCERT Class 11 and 12 + P. Bahadur (Physical Chemistry) | M.S. Chauhan (Organic); J.D. Lee (Inorganic — Coordination and Bonding chapters only) |
| Mathematics | NCERT Class 11 and 12 + NCERT Exemplar (especially Calculus chapters) | S.L. Loney (Trigonometry and Coordinate Geometry); Arihant (Integration) |
| Biology | NCERT Class 11 and 12 (compulsory and sufficient for 70-80 percent of questions) | Truman's Objective Biology (for additional MCQ practice) |
Important: Do not accumulate too many books. One well-studied reference per subject with thorough NCERT coverage will always outperform scattered reading across five books per subject.
8. Frequently Asked Questions
Is NCERT sufficient for IAT Biology?
Do I need JEE-level preparation for IAT Mathematics and Physics?
Which chapters should I completely skip if I have time constraints?
How many years of previous papers should I solve?
Can I use a calculator during IAT?
What is a good mock test score 30 days before IAT?
Can a PCM student get AIR under 100 without Biology preparation?
9. A Final Note on Mindset and Consistency
The IISER Aptitude Test was designed by researchers who want to identify students with genuine scientific curiosity. The examination rewards students who find science interesting enough to think about it deeply — not students who have memorised the most. Every time you find yourself looking up something extra because a concept genuinely fascinated you, you are preparing in exactly the right spirit.
Start today. Build the habit before Class 12 board pressure arrives. The 12 months between now and IAT 2027 are enough to become thoroughly prepared — but only if they are used consistently. Four to five hours of focused, daily preparation from June 2026 will compound into a meaningful advantage by May 2027.
Be systematic. Use the chapter-priority data above to direct your attention. Track your progress with mock tests. And keep the cutoff targets in sight — they tell you exactly how far you need to go.
Next Steps: After understanding the syllabus and preparation roadmap, use the PREP4IISER IAT 2027 Score Calculator and Rank Predictor to track your progress and estimate your rank based on practice test scores.
All chapter-frequency data is derived from IAT question papers 2017–2025. Cutoff figures are from IAT 2025 official results and should be treated as indicative benchmarks. The IAT 2027 syllabus, pattern, and cutoffs are subject to change; always verify with the official IISER admissions portal at iiseradmission.in. No external course or coaching is referenced or endorsed in this article.
Prepared by PREP4IISER — your dedicated resource for IISER Aptitude Test preparation.