NDA vs CDS: Entry, Training & Age Limits

Two exams. Both conducted by UPSC. Both lead to a commission as an officer in the Indian Armed Forces. But the path, the timing, and the experience of getting there are fundamentally different. If you’ve ever dreamed of wearing olive green, white, or blue — understanding the NDA and CDS distinction could shape the next decade of your life.

Who Can Walk Through Which Gate?

This is where the biggest difference lies.

NDA (National Defence Academy) is for candidates who’ve just passed or are appearing in Class 12. You must be an unmarried male, aged 16.5 to 19.5 years. You need Physics and Maths in 12th for Air Force and Navy entries, while Army accepts all streams. NDA is, in essence, a call to arms before you’ve even set foot in a college.

CDS (Combined Defence Services) is for graduates. You need a degree from a recognised university. The age limit varies — up to 24 for IMA (Indian Military Academy), up to 25 for AFA (Air Force Academy), and up to 25 for INA (Indian Naval Academy). OTA (Officers Training Academy) accepts candidates up to 25, and critically, OTA entry through CDS is open to both men and women.

So the first filter is straightforward: still in school or just finished 12th? NDA is your window. Already have a degree or graduating soon? CDS is the route.

Where Do You Train? The Academy Breakdown

NDA cadets go to the National Defence Academy in Khadakwasla, Pune — a sprawling campus where you spend three years getting a degree (from JNU) while simultaneously undergoing military training. After NDA, you move to your respective service academy: IMA Dehradun (Army), AFA Dundigal (Air Force), or INA Ezhimala (Navy) for another year of specialised training. Total: roughly four years before you’re commissioned.

CDS candidates skip the degree part (they already have one) and go directly to the service academy. IMA training is 18 months. OTA Chennai is 49 weeks for Short Service Commission. AFA and INA have their own timelines. You’re looking at 1 to 1.5 years of training before commissioning.

The NDA experience is transformative in a way CDS training cannot replicate — you enter as a teenager and emerge as a fundamentally different person. CDS officers, however, bring the maturity of a college education and real-world exposure.

Exam Pattern: What Are You Preparing For?

NDA Written Exam has two papers:

• Mathematics (300 marks) — covers 10+2 level Maths
• General Ability Test (600 marks) — English, Physics, Chemistry, General Knowledge, History, Geography

Total: 900 marks. The Maths paper is what trips up most candidates. If you’re from a humanities background, you can only apply for Army through NDA, and the Maths paper is still mandatory.

CDS Written Exam has a different flavour:

• English (100 marks)
• General Knowledge (100 marks)
• Elementary Mathematics (100 marks) — only for IMA, AFA, INA entries. OTA skips this.

Total: 200-300 marks depending on the entry. The CDS paper is considered easier in terms of difficulty level, but the competition is fierce since graduates from across the country appear.

Both exams are followed by the real test — the SSB Interview.

The SSB: Where Most Dreams End

Regardless of whether you clear NDA or CDS written, you face the Services Selection Board — a 5-day psychological, physical, and interview assessment that’s unlike any other selection process in India.

Day 1: Screening — Officer Intelligence Rating (OIR) test and Picture Perception & Discussion Test (PPDT). Roughly 50-60% candidates are screened out on Day 1 itself.

Days 2-4: Psychology tests (TAT, WAT, SRT, Self Description), Group Tasks (Group Discussion, Group Planning Exercise, Progressive Group Tasks, obstacles), and a Personal Interview.

Day 5: Conference — the board discusses your case and announces results.

SSB recommendation rates hover around 5-15% of screened-in candidates. This is where the real selection happens. Your written exam rank matters, but the SSB is the make-or-break stage.

The preparation approach is similar for both NDA and CDS SSBs, but NDA candidates are judged with slightly more leniency given their younger age. CDS candidates are expected to demonstrate more maturity and clarity of thought.

Physical Standards You Can’t Ignore

Both entries require you to meet physical standards — minimum height (generally 157.5 cm for Army), weight proportional to height, good eyesight (especially strict for Air Force — 6/6 in each eye for pilot entries), no flat feet, no colour blindness.

NDA candidates have an advantage here — they’re younger, more adaptable, and the NDA training itself builds extraordinary physical fitness over three years. CDS candidates need to arrive at the academy already physically fit.

Career Progression After Commissioning

Here’s the thing most people miss: once commissioned, there is zero difference in rank, pay, or career trajectory between an NDA and CDS officer of the same batch seniority. A Lieutenant is a Lieutenant, regardless of entry.

However, NDA officers commission younger — typically at 21-22 versus 24-25 for CDS. This means:

• They accumulate seniority faster
• They reach Colonel/Brigadier-level ranks at a younger age
• They get more years of service before retirement

In practical terms, if two equally competent officers are compared, the NDA officer will likely reach senior ranks 2-3 years earlier simply because of the head start.

Pay starts at around ₹56,100 (Level 10 of 7th Pay Commission) plus Military Service Pay of ₹15,500, plus DA, allowances, and free accommodation. With all benefits included, a newly commissioned officer’s effective compensation is well above ₹1 lakh per month — and it only grows from there.

Choosing Your Path

If you’re reading this in Class 11 or 12 and the armed forces genuinely excite you — attempt NDA. Don’t wait. The training is more comprehensive, you commission younger, and the NDA alumni network is one of the most powerful professional networks in the country.

If you missed the NDA window or discovered your interest in defence later — CDS is an equally honourable entry. Many decorated officers, including several who’ve reached the highest ranks, entered through CDS.

The uniform doesn’t come with a tag saying which exam you cleared. What matters is that you earned the right to wear it.