The Combined Defence Services Examination (CDSE) — more commonly known as CDS — is one of the most respected defence entrance exams in India. Conducted twice a year by UPSC, it's the gateway to becoming a commissioned officer in the Indian Army, Navy, Air Force, or Officers' Training Academy. If you're serious about a defence career with officer-level entry, this is the exam you need to crack.
Now, what makes CDS unique is its clean, structured syllabus. It's not overwhelming. Three subjects — English, General Knowledge, and Mathematics — cover everything. The real challenge is the depth of preparation and your consistency over time. This page gives you the complete CDS Syllabus 2026, the exam pattern for each academy, the SSB Interview breakdown, and a study strategy that doesn't waste your time.
1. CDS Exam 2026 – Overview
2. Academies Covered Under CDS Exam
CDS is your ticket into four of India's most prestigious military training institutions. Which one you're aiming for determines whether you need to prepare Maths or not:
3. CDS 2026 Eligibility Criteria
| Academy | Educational Qualification | Age Limit | Gender |
|---|---|---|---|
| IMA (Army) | Graduation in any discipline from a recognized university | 19–24 years | Male only |
| INA (Navy) | Engineering degree from a recognized university/institution | 19–24 years | Male only |
| AFA (Air Force) | Graduation with Physics & Maths at 10+2 level, OR Engineering degree | 19–24 years | Male only |
| OTA (Men – SSC) | Graduation in any discipline from a recognized university | 19–25 years | Male |
| OTA (Women – SSC-W) | Graduation in any discipline from a recognized university | 19–25 years | Female |
4. CDS Exam Pattern 2026 – IMA/INA/AFA vs OTA
📊 Paper-wise Marks Summary
| Subject | Marks | Questions | Duration | Applicable For |
|---|---|---|---|---|
| English | 100 | 120 MCQs | 2 Hours | IMA, INA, AFA, OTA |
| General Knowledge | 100 | 120 MCQs | 2 Hours | IMA, INA, AFA, OTA |
| Elementary Mathematics | 100 | 100 MCQs | 2 Hours | IMA, INA, AFA only |
| Total (IMA/INA/AFA) | 300 | 340 | 6 Hours | |
| Total (OTA) | 200 | 240 | 4 Hours |
5. Negative Marking – Understand This Before You Sit for the Exam
For every wrong answer across all CDS papers — English, GK, and Maths — 1/3 of a mark (approximately 0.33 marks) is deducted. This applies to all MCQs. Unattempted questions carry absolutely no penalty — zero marks deducted.
So here's the real math: if you mark 3 wrong answers, you lose 1 full mark. If you're unsure between two options and randomly pick one — you're essentially gambling. The smarter move is to skip when you're less than 60-70% confident. CDS toppers typically attempt 80–90 questions per paper rather than all 120, with very high accuracy on the ones they do attempt.
6. CDS English Syllabus 2026
The English paper is the same for both IMA/INA/AFA and OTA. It tests your command over the language — grammar, vocabulary, reading comprehension, and sentence structure. The level is roughly Class 12 to early graduation standard.
- Spotting Errors in sentences
- Sentence Improvement & Correction
- Fill in the Blanks – Grammar rules
- Voice Change – Active to Passive
- Narration – Direct to Indirect Speech
- Parts of Speech – Nouns, Pronouns, Verbs
- Articles, Prepositions, Conjunctions
- Tenses – Present, Past, Future forms
- Synonyms and Antonyms
- One Word Substitution
- Idioms and Phrases
- Reading Comprehension Passages
- Ordering of Sentences in a Passage
- Ordering of Words in a Sentence
- Words often Confused (Homophones)
- Cloze Test – Fill in blanks in passages
7. General Knowledge Syllabus 2026
The GK paper is the widest section — it covers everything from Indian History to current scientific developments. But don't let that intimidate you. The question level is designed to test a well-read graduate, not a specialist. Here's exactly what you need to cover:
- Ancient India – Indus Valley, Vedic Period
- Medieval India – Delhi Sultanate, Mughal Empire
- Modern India – British Rule, Social Reforms
- Indian National Movement – Freedom Struggle
- Role of Bihar in Independence (Gandhi, Champaran)
- Post-Independence India
- Important Personalities & Events
- Salient Features of Indian Constitution
- Fundamental Rights, DPSP, Fundamental Duties
- Parliament – Lok Sabha & Rajya Sabha
- Executive – President, PM, Council of Ministers
- Judiciary – Supreme Court, High Courts
- State Government Structure
- Elections & Election Commission of India
- Important Constitutional Amendments
- Physical Geography – Landforms, Climate, Rivers
- Indian Geography – States, Capitals, Rivers, Mountains
- World Geography – Continents, Oceans, Major Countries
- Economic Geography – Agriculture, Industries, Trade
- Soils, Vegetation & Natural Resources of India
- Climate Zones & Monsoon in India
- Major Ports & Airport of India
- Basics of Economic Planning in India
- Budget – Revenue & Capital
- Inflation – Types & Causes
- Banking System – RBI & Monetary Policy
- Agriculture & Rural Economy
- Major Government Economic Schemes
- International Trade & Balance of Payments
- Physics – Motion, Force, Energy, Sound, Light
- Chemistry – Elements, Compounds, Reactions
- Biology – Human Body, Diseases, Nutrition, Cell
- Environmental Science & Ecology
- Space Science – ISRO Missions, Satellites
- Defence Technology & Weapons Systems
- Recent Scientific Inventions & Discoveries
- National & International News (last 12 months)
- India's Defence News – Exercises, Acquisitions
- Sports – Awards, World Records, Competitions
- Awards & Honours – National & International
- Important Government Schemes 2025–26
- Summits, Meetings & International Events
- Important Books & Authors (Defence context)
8. Elementary Mathematics Syllabus 2026 (IMA/INA/AFA Only)
Good news — the Maths syllabus for CDS is based on Class 10th standard. It's not the engineering-level Maths of GATE or even the depth of UPSC Civil Services. If you were decent at Maths in school, this section is completely manageable with focused preparation.
- Number System – Natural, Integer, Rational numbers
- Elementary Number Theory – Divisibility, Factors, Primes
- HCF & LCM
- Ratio & Proportion
- Percentage
- Simple & Compound Interest
- Profit, Loss & Discount
- Time, Speed & Distance
- Time & Work
- Average & Mixture & Alligation
- Basic Operations on Algebraic Expressions
- Factors & Remainder Theorem
- H.C.F. and L.C.M. of Polynomials
- Quadratic Equations – Roots & Discriminant
- Linear Equations – 2 & 3 variables
- Logarithms – Laws and Applications
- Set Language & Set Notation
- Sine, Cosine, Tangent & their Reciprocals
- Trigonometric Identities
- Values of trigonometric ratios (0, 30, 45, 60, 90 degrees)
- Heights and Distances
- Use of Trigonometric Tables
- Lines & Angles – Properties
- Triangles – Congruence & Similarity
- Circles – Chords, Tangents, Arcs
- Quadrilaterals – Parallelogram, Rectangle, Square
- Polygons – Regular, Sum of Angles
- Concurrence of medians, altitudes & angle bisectors
- Areas of Squares, Rectangles, Parallelograms, Triangles, Circles
- Areas of Figures Decomposable into Plane Figures
- Surface Area & Volume – Cuboid, Cylinder, Cone, Sphere
- Collection & Tabulation of Statistical Data
- Graphical Representation – Bar Graph, Pie Chart, Histogram
- Measures of Central Tendency – Mean, Median, Mode
- Frequency Polygon & Ogive
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