Hi Aliya,

Opting to pursue B arch after completing diploma in architecture is a great choice. Usually after diploma, lateral entry is given directly to the second year of the course. So you will have to study for 4 years in order to complete the b arch program with the regular students as the total duration of the program is 5 years. 

 If you have done Diploma in Architecture, You can only take admission in 1st year Bachelor of Architecture (B.Arch) program after getting a valid score in NATA entrance exams. 

Some of the best colleges in India that permit lateral entry includes :

• Anna University, Tamil Nadu
• Jadavpur University, Kolkata
• Thapar Institute Of Engineering & Technology, Punjab
• PSG College Of Technology, Coimbatore
• Amity University, Uttar Pradesh
• Manipal Institute Of Technology, Manipal
• Delhi Technological University [DTU], Delhi
• College of Engineering [COEP], Pune
• Kalinga Institute Of Industrial Technology [KIIT], Bhubaneswar
• Pondicherry College Of Engineering [PEC], Puducherry

Hope this helps.

All the best !!!!