CDS Full Form: What the Exam Is, and Who Is Actually Eligible

What CDS stands for

CDS is the Combined Defence Services Examination. The Union Public Service Commission runs it twice a year, as CDS 1 and CDS 2, and it is the main graduate entry route to a commission in the Indian Armed Forces.

The word doing the work is combined. Before this exam existed, each academy ran its own recruitment. Today one written paper feeds four separate training academies across three services, and you tell UPSC on the application form which of them you want to be considered for. Many candidates tick more than one.

The four academies behind one exam

That last row is the one worth reading twice. OTA leads to a short service commission, which runs for a fixed term with the option to extend or to seek a permanent commission later. The other three put you on a permanent commission from the start. Candidates often rank OTA last for this reason, then discover that OTA has the widest eligibility and the shortest paper.

Who can actually sit it

This is where most of the confusion lives, because people read one age limit somewhere and assume it applies across the board. It does not.

UPSC states eligibility as a birth date window, not as an age in years. The notification gives two exact dates and you either fall inside them or you do not. The INA and AFA windows are narrower than the IMA window and have shifted between cycles, which is why this table gives a band for the two stable ones and says narrower for the rest. Read the live notification and work from the dates, never from a secondhand number.

The degree requirement catches more people than the age limit

If you hold a BA, a BCom or a BSc, IMA and OTA are open to you and INA is not. The Naval Academy entry asks for an engineering degree, and the Air Force Academy asks either for an engineering degree or for a degree backed by Physics and Maths at Class 12.

Final year students can usually apply, on the understanding that proof of passing has to be produced by a deadline stated in the notification. Miss that deadline and the candidature goes, however well you did in the written paper.

The marital status rule is real and it is enforced

Candidates for IMA, INA and AFA must be unmarried, and marrying during training means dismissal and recovery of training costs. OTA is where the rules open up, including for women candidates. This is not a formality that gets waived, and it is worth knowing before you plan around it.

What the written paper looks like

The paper you sit depends on which academies you applied for. IMA, INA and AFA candidates sit three subjects. OTA candidates sit two, because Elementary Mathematics is dropped.

Every paper is objective and offline, on paper rather than screen. One third of a mark is deducted for each wrong answer. UPSC also sets a minimum in each individual subject, so a candidate who scores heavily in General Knowledge and collapses in Mathematics can be knocked out despite a healthy total.

Elementary Mathematics is pitched at roughly Class 10 level, which sounds reassuring and is not. The difficulty sits in the volume of questions against the clock rather than in the concepts, and that is a pacing problem rather than a syllabus problem. It is also the problem that timed practice actually fixes.

The half of the exam people forget to plan for

Clearing the written paper does not put you anywhere near selection. It gets you an SSB interview, and the SSB carries exactly the same marks as the written exam.

The SSB runs across roughly five days and covers screening tests, psychological assessment, group tasks and a personal interview, followed by a medical. A large share of candidates are sent home on day one at the screening stage, which has nothing to do with how well you did in the written paper. Half your final marks sit in a process you cannot revise for in the usual sense, and that is worth knowing a year in advance rather than a week before.

CDS and NDA are not the same exam

Both are UPSC defence exams and the names get mixed up constantly. The difference is simply when you sit them.

A graduate cannot apply to NDA, having aged out of it. Someone who missed NDA at 18 has not missed the forces, because CDS reopens the same door a few years later.

Browse the defence exams and mock tests available on Future Topper: defence mock tests

Frequently asked questions

What is the full form of CDS?

Combined Defence Services Examination. UPSC conducts it twice a year for entry to the Indian Military Academy, the Indian Naval Academy, the Air Force Academy and the Officers Training Academy.

Can women apply for CDS?

Yes, through the Officers Training Academy entry, which leads to a short service commission. The IMA, INA and AFA entries through this exam are for male candidates.

Is Mathematics compulsory in CDS?

Only for IMA, INA and AFA candidates. The OTA paper covers English and General Knowledge alone, which is why candidates who are weak in Mathematics often apply to OTA only.

Can a BA graduate apply for CDS?

Yes, to IMA and OTA, both of which accept any bachelor degree. INA requires an engineering degree and AFA requires either an engineering degree or Physics and Maths at Class 12.

Is there negative marking in CDS?

Yes, one third of a mark for every wrong answer in each paper. There is also a minimum you must reach in each subject separately, not just an overall total.

Disclaimer: Age windows, academy entries and eligibility conditions are set by UPSC in each notification and have changed between cycles. The details above reflect recent notifications and are given for general guidance. Always confirm against the current notification on upsc.gov.in before applying.