NDA Entrance Exam National Defence Academy or NDA is one of the most sought-after defence entrance exams in the country. The exam is conducted for admission to Army, Navy and Air Force wings of NDA and Indian Naval Academy Course (INAC). NDA is conducted twice a year in two stages: written exam and SSB Interview. Age limit: For NDA 1 exam, both male and female candidates must have born not earlier than July 2, 2002, and not later than July 1, 2005. For NDA 2 exam, both male and female candidates must have born not earlier than January 2, 2003, and not later than January 1, 2006.