CDS Exam Guide: Eligibility, Pattern and SSB Preparation

The Combined Defence Services (CDS) exam, conducted by UPSC, is the graduate-entry route into officer training at the Indian Military Academy, Indian Naval Academy, Air Force Academy and Officers Training Academy. Unlike NDA, which recruits straight after school, CDS is open to graduates and offers multiple entry points depending on the academy and course you are targeting.

This guide explains who is eligible, how the written exam differs slightly by academy, what the SSB interview stage involves, and how to prepare for an exam that tests academics and character together.

What the CDS exam covers

CDS is the standard graduate-entry pathway for officer commissions across the Army, Navy and Air Force, plus the Officers Training Academy for Short Service Commission entries. Depending on which academy and course you apply for, the exact written papers differ slightly, but the underlying purpose is the same: identify graduates suited to officer training and leadership roles in the armed forces.

Eligibility in general terms

Candidates generally need a graduate degree, with engineering or science-stream degrees required for certain Air Force and Naval entries, and age limits that differ by academy — generally in the early-to-mid twenties range, with variation between entries. Marital status requirements and physical/medical standards also vary by academy and gender. Because eligibility, degree requirements and age brackets differ meaningfully between IMA, INA, AFA and OTA entries and are set per notification, check the current details on upsc.gov.in.

Exam pattern and stages

For IMA, INA and AFA entries, the written exam consists of three papers — English, General Knowledge, and Elementary Mathematics. For OTA (non-technical) entry, only English and General Knowledge are tested, without a Mathematics paper. Candidates who clear the written exam and required cut-offs proceed to the SSB interview, a multi-day assessment of psychological aptitude, group tasks and a personal interview, followed by a medical examination for recommended candidates. Confirm the exact paper-wise marks, cut-offs and SSB process for your target entry in the current official notification, since details can change between recruitment cycles.

Syllabus highlights

• English — grammar, vocabulary, comprehension, synonyms/antonyms and sentence correction.
• General Knowledge — current events, history, geography, polity, economy and general science.
• Elementary Mathematics (IMA/INA/AFA only) — arithmetic, algebra, trigonometry, geometry, mensuration and statistics at a Class 10-12 level.
• SSB assessment areas — psychological tests, group tasks and a personal interview evaluating officer-like qualities.

A preparation strategy for CDS

Build a steady, wide-ranging General Knowledge base through daily current-affairs reading and revision of static topics like history, geography and polity, since this section is common to every entry type. If Mathematics applies to your target academy, revise systematically from Class 10-12 material and practise regularly, since it is a scoring section for well-prepared candidates.

1. Cover English grammar and comprehension through regular practice.
2. Build General Knowledge steadily with daily reading and periodic revision of static topics.
3. Revise Elementary Mathematics from school-level texts if applying for IMA/INA/AFA entries.
4. Begin SSB-oriented preparation — fitness, current affairs depth, and group task familiarity — well ahead of the written result.

Common mistakes to avoid

A frequent mistake is applying for an entry without checking its specific degree and physical eligibility carefully, since requirements genuinely differ between IMA, INA, AFA and OTA. Another is under-preparing General Knowledge because it feels broad and unfocused; a steady daily habit over several months closes this gap far more reliably than sporadic intense study close to the exam.

Frequently asked questions