CDS Exam — The Complete Guide to Combined Defence Services
For graduates. Held twice a year by the UPSC. Four academies — IMA, INA, AFA, OTA. Two commission tracks — Permanent and Short Service. This is the full picture from eligibility to commissioning, with the splits and cutoffs that actually matter.
1. What CDS is
The Combined Defence Services Examination is the UPSC's graduate-entry pathway into the Indian Armed Forces. It is run twice each year (notifications typically open in October/November and June/July, with exam dates in February — CDS-I — and November — CDS-II). It feeds four academies:
- IMA, Dehradun — 1-year Pre-Commission training for Army. Permanent Commission on passing out as a Lieutenant.
- INA, Ezhimala — Pre-Commission training for Navy (typically engineering-degree entry). Permanent Commission as a Sub-Lieutenant.
- AFA, Dundigal — Air Force Academy training for the Flying Branch (or specific Ground Duty Branches per the cycle). Permanent Commission as a Flying Officer.
- OTA, Chennai — Officers Training Academy. Short Service Commission. Open to both men and women. Commissioning as a Lieutenant after ~49 weeks.
2. Eligibility — by academy
Age windows are narrow and birth-date specific. The UPSC notification publishes exact "born not earlier than X and not later than Y" dates for each cycle — verify your eligibility against those exact dates before applying.
Indian male citizen (or eligible category). Age window typically 19–24 (e.g. ~19 to ~24 years on the first day of the month of joining). Bachelor's degree from a recognised university in any discipline. Final-year students can apply, conditional on producing the degree before joining.
Indian male citizen. Age window typically 19–24. Bachelor's degree in Engineering from a recognised university (specific streams as listed in the UPSC notification). Final-year engineering students can apply, conditional on producing the degree before joining.
Indian male citizen. Age window typically 20–24 (a candidate holding a Commercial Pilot License issued by DGCA may get an upper-age relaxation per the notification). Bachelor's degree in any discipline with Physics and Mathematics at 10+2; OR Bachelor of Engineering. Refer the UPSC notification for exact qualification list.
Indian citizen — BOTH men and women. Age window typically 19–25. Bachelor's degree from a recognised university in any discipline. Final-year students can apply, conditional on producing the degree before joining. SSC route — non-technical men, women (Non-Technical), and Women (Non-Technical).
Marital status. For IMA, INA and AFA candidates must be unmarried (and remain so until commissioning). For OTA, candidates may be married, but marital status requirements during training are governed by Academy rules — verify the current OTA Joining Instructions before applying.
3. Written exam pattern
CDS has two paper structures depending on the academy you are applying to.
- English — 100 marks, 2 hours
- General Knowledge — 100 marks, 2 hours
- Elementary Mathematics — 100 marks, 2 hours
- Total: 300 marks · Three papers · MCQ · Negative marking
- English — 100 marks, 2 hours
- General Knowledge — 100 marks, 2 hours
- No Elementary Mathematics paper.
- Total: 200 marks · Two papers · MCQ · Negative marking
Syllabus (per UPSC notification)
- English — comprehension, grammar, usage, vocabulary. Standard of a graduate.
- General Knowledge — current affairs, history, polity, geography, economics, science, defence-related awareness.
- Elementary Mathematics — arithmetic, algebra, trigonometry, geometry, mensuration, statistics. Class X / Matriculation standard.
CDS is graduate-level, but Elementary Mathematics is Class X standard — engineers find it easy; commerce / arts graduates need real preparation. Plan accordingly. OTA-only aspirants skip Maths entirely — verify your form selection so you are not entered for the wrong paper structure.
4. SSB Interview — identical 5-day process
Candidates who clear the written are called for the same Services Selection Board interview used for NDA: 5 days at one of the four selection centres. The structure is identical to NDA — Day 1 Screening (OIR + PPDT), Day 2 Psych (TAT, WAT, SRT, SD), Day 3–4 GTO + Personal Interview, Day 5 Conference. CDS SSB carries 300 marks (matching the written 300 marks for IMA/INA/AFA) and 200 marks for OTA candidates.
The 5-day SSB is described day-by-day in our NDA Exam Complete Guide — same Screening, same Psych, same GTO, same Conference. Refer that section.
5. Cutoff trends
UPSC publishes academy-wise written and final cutoffs for each CDS cycle. Historical ranges (illustrative — always verify against the live UPSC results page):
Source: UPSC CDS Examination results, last several cycles. Refer the specific year's notification & result PDF on upsc.gov.in for exact published cutoffs.
6. Permanent Commission vs Short Service Commission
The biggest career decision a CDS candidate makes is which academy to mark first preference — and that decision is fundamentally a choice between Permanent Commission (PC) and Short Service Commission (SSC).
- Career until superannuation (rank-based retirement age)
- Pension after 20 years qualifying service
- Promotion eligibility through full rank ladder
- Staff College & Higher Command schools open
- Bond commitments may apply (flying, specialist courses)
- 10-year initial commission, extendable to 14 years
- Open to both men and women (OTA Chennai)
- Eligible for PC consideration after qualifying service (subject to vacancies and selection)
- Same pay scale as PC officers during service
- No service pension if released before 20 years qualifying service — Gratuity only
On 17 February 2020, the Supreme Court of India in Secretary, Ministry of Defence v. Babita Puniya & Ors held that women SSC officers in eligible Army arms/services are entitled to consideration for Permanent Commission on the same basis as their male counterparts. The Ministry of Defence subsequently issued implementation orders. A similar ruling for the Navy followed. What this means in practice: a woman officer commissioned through CDS-OTA can — subject to vacancies, selection, and her arm/service — convert to Permanent Commission after the qualifying period.
7. Pay during training and on commissioning
Identical to NDA-route officers. Cadets at IMA / INA / AFA / OTA receive a fixed stipend during training (₹56,100/month per latest published MoD orders — Pay Level 10 Cell 1). On commissioning, the full Lieutenant pay (basic + MSP + DA + allowances) commences. There is no PC vs SSC pay difference during service.
Open the 7th CPC Pay Calculator→8. Sources
- UPSC — Combined Defence Services Examination notifications and results (upsc.gov.in)
- Indian Military Academy, Dehradun — official course details
- Indian Naval Academy, Ezhimala — official course details
- Air Force Academy, Dundigal — official course details
- Officers Training Academy, Chennai — official course details
- Ministry of Defence — Pay rules, DA notifications, 7th CPC implementation
- Supreme Court of India — Secretary, Ministry of Defence v. Babita Puniya & Ors (17 Feb 2020)
- Seventh Central Pay Commission Report (2016), Government of India