INMO

INMO

INMO — The Indian National Mathematical Olympiad.

Six proof-based problems in four and a half hours: pattern, selection, topics and past papers.

Start Preparing →
Selection

How Students Reach INMO.

Top RMO performers from each region are invited to INMO.

See Selection →
Depth

National-Level Problem Solving.

Harder, longer problems that need deep ideas and complete proofs.

See Topics →
Practice

Solve Past INMO Papers.

Work through real INMO problems and compare with model solutions.

Practise Now →
Next Stage

Aim for IMOTC and the IMO.

Top INMO performers are invited to the training camp that selects India’s IMO team.

See the Pathway →

INMO at a Glance

The Indian National Mathematical Olympiad is the third stage of India’s Mathematical Olympiad programme and the gateway to the IMO Training Camp.

Conducted byHBCSE
Who can appearRMO qualifiers
ModeWritten, pen and paper
Duration4.5 hours
Problems6, proof-based
Total marksUsually 102 (17 each)
Partial creditYes
Next stageIMOTC

Based on recent INMO papers. Always confirm the current rules on olympiads.hbcse.tifr.res.in.

Where INMO Fits

The Mathematical Olympiad pathway, from IOQM to the IMO.

IOQM

Qualifier exam — 30 integer-answer problems. IOQM page →

RMO

Regional Mathematical Olympiad — 6 proof-based problems in 3 hours. RMO page →

INMO

Indian National Mathematical Olympiad — 6 proof-based problems in 4.5 hours.

IMOTC

Training camp at HBCSE for top INMO performers.

IMO

India’s team of six is selected for the International Mathematical Olympiad.

Selection from RMO

INMO seats are given region by region, based on RMO scores. Numbers below are from the latest announced rules.

INMO selection from RMO, per region (recent rules)
Group (per region)Selected
Category A — Class 8 to 11Top 30
Category B — Class 12Top 6
Girls, Category A5 more

A non-zero RMO score is needed; ties are broken using IOQM scores. Rules can change each year — check olympiads.hbcse.tifr.res.in.

INMO Pattern

Six problems in four and a half hours — about 45 minutes per problem. Every solution must be written out in full.

INMO paper structure (recent papers)
ItemDetail
Problems6
Marks per problem17
Duration270 min
Answer typeWritten proofs
Total marks102

6 × 17 = 102 marks; 270 ÷ 6 = 45 minutes per problem on average.

INMO Topics and Techniques

Pre-college mathematics, no calculus — at national-olympiad depth. Tap a topic to see its areas.

AlgebraNational level
  1. Polynomials — roots, irreducibility, interpolation
  2. Inequalities — AM-GM, Cauchy-Schwarz, Schur, Jensen
  3. Functional equations over integers and reals
  4. Sequences, recurrences and complex numbers
Number TheoryNational level
  1. Congruences, orders and primitive roots
  2. Quadratic residues
  3. Diophantine equations and p-adic valuation
  4. Lifting the exponent; Zsigmondy-type ideas
GeometryNational level
  1. Cyclic configurations and angle chasing
  2. Power of a point, radical axes and centres
  3. Homothety, spiral similarity and inversion
  4. Trigonometric, complex and barycentric methods
CombinatoricsNational level
  1. Advanced counting, bijections and generating ideas
  2. Invariants, monovariants and extremal principle
  3. Graph theory
  4. Combinatorial geometry and games
Proof TechniquesUsed across all topics
  1. Induction (including strong and structural)
  2. Contradiction and infinite descent
  3. Pigeonhole and double counting
  4. Extremal principle and smoothing
  5. Constructions and counter-examples

Free INMO Study Material

Advanced theory, solved examples and problem sets at INMO level.

These resources are being added topic by topic. Pages marked “Coming soon” are not published yet.

INMO Practice

Write full solutions under exam conditions, then compare with model solutions.

Under development. The practice sets below are planned and will open here when ready.

Coming soon

Problem of the Week

  • Problems: 1 a week
  • Level: INMO
  • Topics: Rotating
  • Solution: Next week

INMO Previous-Year Papers

Problems with complete model solutions, arranged by year.

Coming soon. Official question papers are published by HBCSE on olympiads.hbcse.tifr.res.in.

How to Prepare for INMO

Between RMO (November) and INMO (January) there are only about nine weeks — use them well.

Fill topic gaps

Review your RMO paper and strengthen the weakest of the four topics first.

Learn advanced tools

Add inversion, orders, LTE, Schur and graph ideas to your toolkit with solved examples.

Solve past INMO papers

Attempt full papers under a 4.5-hour limit.

Stay with hard problems

Spend an hour or more on a single problem before reading its solution.

Write and get feedback

Write complete proofs and have a teacher or friend check them for gaps.

Manage time in the exam

Read all six problems first, start with the most approachable, and write partial progress.

INMO 2027 Date

INMO 2027 is scheduled for 17 January 2027, 12:00 noon to 4:30 PM. Always check the official website. We will post verified updates here.

Official Olympiad Website ↗

INMO FAQs

Who conducts INMO?

INMO is conducted by the Homi Bhabha Centre for Science Education (HBCSE) as part of India’s Mathematical Olympiad programme. Official information is on olympiads.hbcse.tifr.res.in.

How do I qualify for INMO?

Through RMO. In recent years about the top 30 Class 8–11 students and the top 6 Class 12 students from each region were selected, plus additional seats for girls. Check the current year’s rules on the official website.

How is INMO different from RMO?

Both are proof-based with six problems, but INMO allows 4.5 hours instead of 3, and the problems are harder and need deeper ideas.

Are partial marks given?

Yes. Graders give credit for correct, meaningful progress, such as a proven lemma or a solved important case.

What happens after INMO?

Top INMO performers are invited to the International Mathematical Olympiad Training Camp (IMOTC) at HBCSE. India’s IMO team of six — and the team for the European Girls’ Mathematical Olympiad (EGMO) — is selected from the camp.

What can I take into the exam?

Usually pens, pencils, a ruler and a compass. Calculators, protractors and electronic devices are not allowed. Follow the instructions on your admit card.